Writer Steven Marsh with Mike Stahl of Stahl-Tek. Marsh looks like a cop in real life. Tough. Mean. Like he'd just as soon bust yer face. Okay, maybe not, but I'm always surprised when a writer looks like a football player.
“Audio as a hobby is dying, largely by its own hand. As far as the real world is concerned, High-End audio lost its credibility during the 1980s, when it flatly refused to submit to the kind of basic honesty controls (double-blind testing, for example) that had legitimized every other serious scientific endeavor since Pascal. [This refusal] is a source of endless derisive amusement among rational people and of perpetual embarrassment for me..”
Gordon J Holt, founder
I have commented many times about this Gordon J Holt's statement. From a purely commercial point of view, the Hi-End Audio market may be fuller than ever just when having a look at its large offer (quantity) of products. From a technological point of view, and for many decades, I can see only many different, no, ...thousands of ! versions of the same themes: turntables, preamps, amplifiers, cables and... loudspeakers. Oh my God... it seems we are so used to see them that our brain only works to choose among the most beautiful one. Does anybody cares about how to really improve a High Fidelity SYSTEM ? Mostly, not. Only some of Hi-End manufacturers seems to have the know-how and so, they offer some technological truth... after making you spend a good lot of money in the journey, of course.
OK, let's go to the main subject here: my recent journey to a company that seems not to care about what most people appreciate (following the commercial stream is always more comfortable, right?) but about what the technology can offer for the perfect reproduction of our sound-sources (whatever they may be: analog or digital).
One of my best friends (sorry to keep his name in secret but he always prefer to hide himself behind the products and/or his work) told me that he was preparing a fast trip to Germany to visit a manufacturer who had developed for years one of the most accurate transducers in the world.
-“Another speaker manufacturer ?” I sadly asked,
-“Nop. Don´t expect so. I think I am going to meet, listen and talk to one of the most incredible manufacturers in the world: Manger.” he answered.
-“Sure...Where are they from this time? ...and what kind of loudspeaker are they making ?” I must recognize that I was just wishing that he would answer with a topic brand just to deny his invitation.
-“They are in Mellrichstadt. 170 kms away from Frankfurt. And, no, it is not the kind of regular “speaker”. In fact, it has never been that. It's a long journey... would you like to come with me ? I don't mind having an extra-driver and a second point of... hearing”.
The truth is that this guy has been professionally involved in the Hi-End Audio for a long time. As a very close friend of him, I have had the opportunity to follow his professional evolution since he started with his Quad as a simple amateur, his different jobs and positions in the business for almost 20 years, as well as the number of ultra-expensive gear he have had the chance to play with (Wilsons, Apogees, Sonus Fabers, Vienna Acoustics, Martin Logans, Tannoys, etc. )... until he resigned his position exahusted of, according to his words, a completely saturated market that, technologically, it has absolutely nothing new to offer since many years ago: just distracting users with a hypnotizing rainbow of colors, romantic tube amps & SS macho-chassis amplifiers and the typical equalization with cables to compensate the average accuracy of those brands. Now, after many years of hopeless, he was saying that he had found something really new. New for him ? Then I wanted to be part of the discovery !
I prefer to avoid the always funny anecdotes during the flight, driving some kilometers through those German highways. In the mean(long)time I mentally checked most of the German Hi-End Audio brands I knew. Germany... the eternal fiancée in the Hi-End market. Probably the most powerful economy in Europe that hardly seems to find its place in the worldwide audio Hi-End market. Well, there's an easy explanation for that: we all know (or just think?) that Germans listen to music in a different way, right ? Well, NO. It is just that: I'm afraid an easy excuse to release our minds. At the end, they already have Porsche, BMW, Audi, Volkswagen... Enough ! True Hi-End is related to US, UK, Italy and, if you push me, even Italy ! German Hi-End Audio is for Germans. Period. Period followed... I should say.
My “brother” had made an appointment with the owner of the company, Daniela Manger, daughter of Joseph Manger, creator of a new kind of “transducer” (“new” for us, I mean) at 10:00 AM at the hall of a very close hotel.
Mrs. Manger is not running the company only because of being her father's daughter: she is a true Ph. D. Engineer. Good start: most of Hi-End loudspeaker manufacturers don´t have a degree in anything related to acoustics, sound, electricity, mechanics, etc. I have known of dentists, otolaryngologists, or... mostly, simply amateurs. Few real professionals in the field but who cares? People will eat whatever you put on the dish: they are hungry. Again, aesthetics (furniture?), matter. For Hi-Technology and precision, please, go to the bottom, second door on the right.
10:00 AM. Here we are. German precision: here she is. There we go.
This was the planning: we would listen for a (long)while the new floor-standing model (MSMs1) and I would be allowed to join to the professional meeting with her (a kind of 'ForYourEarsOnly' matter), then a lunch (short break), meeting again and visit to the facilities. We were only asked one thing: no comments about their technology and, as much as possible, no images/pics of the manufacturing-room: the place where all Manger transducers are, still, handcrafted manufactured, tested and then, installed.
I'll go directly to the system without entering in too many details: a Mac, a German DAC, a German Preamp connected through XLR directly to the minimalistic (monolithic?) pair of MSMs1.
My tracks ? Some typical audiophile & not-so audiophile recordings:
The Lover of Beirut / Spagna Contrapunto / Chan-chan / In your hands / Blue Moon revisited / Hotel California / In my Father's House / Maria-Maria / Girl from Ipanema / SuperBass Theme / Yulunga / + many, many classical music with full orchestra at its best (Wagner, Mahler, and some Beethoven's string quartets).
Plus, a very interesting Demo-CD that Manger offers: “Musik wie von einem anderen Stern”. There is also a double Lp version with some excellent professional reviews as well as CD got from end-users.
Don´t want to bother you with the typical audiophile verbiage: “sweet/velvet medium & treble frequencies”, “tight bass”, “holographic soundstage”, etc. Nor even with all the technical details that surrounds this unique product: you can visit Manger website for very deep technical information until you get enough... there is much to read about it. I am only a disappointed ex-audiophile. But, again, somehow I find it hard not to expose some of his masterful technical details.
The new MSMs1 is what the recording is. No mercy, here. Period.
Oh, well, for years... didn't we pray on our knees for a system that, finally, could reveal all what is inside the recording ? So, here you have it. From now you'll 'only' need the best source you can afford: turntable, cartridge, phono-preamp, preamp, interconnect cables, DAC,... you still have a lot of things to take care of, dear music-lover.
Don't worry about the rest: the new MSMs1 will show what you have behind of it. For good or for bad. A kind of ultra-high precision stereo-microscope equipped with the best Zeiss lenses ? Absolutely !
Have you ever tried to close your eyes while seating down in a concert ? Surprising, isn't it ? No Hi-Fi, no Hi-End... everything is so natural. Same here... but only when the recording/mixing/mastering process has been properly applied.
But there is more. Much more. In fact, there is a lot behind this unique 'transducer'... So, after the audio-test, I joined the meeting now with religious obedience... We needed explanations. We were hungry for information.
And the explanations began... As Mr. Manger once said: “You have to swim against the stream if you really want to reach the source”. Sound-source, I clarify. Describing what the Manger transducer is would take many pages. Frankly writing, I can nothing but recommend you to visit their website and read carefully all the technical explanations about its principle, how it works, and how hard it's been to reach the grade of highest perfection we can now enjoy. What I can tell you is, if there is an almost perfect transducer in the world, nowadays, this is Manger's. It has taken more than 30 years to get such accuracy and we are lucky to be able to listen our recordings through it. For example...
...Should I mention this transducer (I resist myself to simply call it, merely, “speaker”) is capable of reproducing from down 80 Hz up to almost 40.000 Hz ? So, those SACDs, DVDAudio, HiDef music files, etc. are in luck : all of you are welcome !
...Because of that, it means that it can manage an ultra wide-band range of frequencies without the typical crossover point around 1000-2000 Hz (precisely where the human ear is more sensitive). Besides, due to the fact that this model (as well as its reference studio-monitor smaller brother, the MSMc1) is purely active, you don´t have to play the role of a real electronic-engineer searching for the best food/amplification for the transducer and its woofer: it has already professionally matched with 2 dedicated mono-power amplifiers located externally at the back: the Manger transducer, plus, the dedicated (almost sub)woofer have what they deserve. Think also about the amount of money (and wasted time) you save: no need to care about any loudspeaker cable. 4 power-amplifiers connected directly to the transducers and woofers with no intermediaries. Oh, God, ...what a bless !
Just connect an XLR cable from your preamp (or DAC), switch it on and you'll become into the mastering engineer. So easy...
I'm afraid that, again, that terrible die-hard audiophile inside of my friend is re-born again. We need to stop our hear-beats for a while. Lunch time comes to our almost heart-attack's rescue: a short-break. These Germans never rest: 1 hour for a short-lunch while we were delighted sharing anecdotes and discussing about the Professional and Hi-End worlds... and back to their facilities again. Because Manger MSMs1 is not a dedicated Hi-End product but a mandatory professional tool: you really have to check Manger website to see what Joseph Manger thinks about what should be the role of a perfect transducer. You can also be surprised how, against all technical prejudices, even from some of the most eminent scientists, they had to recognize that it is the right one. After reading it you will understand the incredibly task it does... turning all the running AC energy in another form (bending waves) with the minimum of waste of energy: the problem of conventional drivers is the energy stored in the diaphragm by mass and spring, which ALWAYS causes time delays.
As I told you, there was even 'more': Time has come to enter into the 'Holy-Grail' room. But you won´t see a line of robots untiringly soldering pieces without time to answer any question. Either you won´t see a line of 100 employees steadily working like soldiers. But what you can see there is love and pure passion for a perfect handcrafted product. And there you can know many things like the fact that most of the machines there have also been designed by Joseph Manger himself (he is 81 y.o., still up and now working on a new microphone design).
Excuse me, did I mention he has received the Diesel Medal for his revolutionary 'transducer' ?
...that he also designed some of the exclusive materials that are necessary to handcraft it ?
Well, sorry, so many things... Oh, yes, I also forgot to say that a few very well specialized small group of women are carefully mounting each part. But I guess that then, I should let you know the large number of hours that it takes to finish only 1 (pc) Manger transducer. As well as the number of patents that this astonishing instrument has on it.
I should add that the MSMc1 (the reference active-monitor model) has a dedicated stand: fixed (customized) or... gas suspension (!). Your choice. You have also the passive models versions, specially dedicated to those who want to enjoy their own power-amps (no matter, tubes or solid-state... read this).
After this long visit, an expression comes into my mind: passion & care for the highest accuracy in sound reproduction. Something that I haven't noticed so clearly on some manufacturers facilities I have had the chance to visit.
During the last year I have always been asking my friend why he left the business, commenting about all those new tweeter+woofer+beautiful cabinets that year after year appear on (and disappear from) the market. And his answer has always been the same: “Always same dogs, just with different collars” i.e.: hundreds of different manufacturers using same scheme (tweeter+woofer) adding his 'personal touch' based only on an old passive crossover plus a beautiful cabinet for a hungry group of amateurs who, mostly, only appreciate the aesthetics. Once they are tired of them and their sound, they put them aside to buy another similar one.
I can only thank Mrs. Manger for interrupting her daily hard work and for her infinite patience answering all our questions, as well as her love for perfectionism.
I guess it's the best a father can transmit to his daughter and she has clearly accepted and followed the family tradition.
What a gift for the connoisseurs ! But, how many of us could know about the existence of such 'jewel' ? Unfortunately, this is not a product for any wallet. Somehow, it uses to happen: surely everybody knows about Rolex... then, only a few know about Breguet or Vacheron Constantin. Same with the Manger transducer.
I can assure you that real audio handcrafted perfection exists and I have been lucky enough to listen to it. My friend has regained some of his lost faith in Hi-End audio technology.
At the end, and as Mrs. Manger's leitmotiv says:
“Precision, in sound, is just a matter of time”.
Now that my speakers are set up in an equilateral triangle, let’s take some frequency response measurements. First we need a calibrated microphone, software to perform the measurements, and a sound card. While there are several choices of measurement mics, acoustic measurement software, and sound cards, I will be using a MP-1r-KIT Acoustical measurement kit:" http://www.content.ibf-acoustic.com/catalog/product_info.php?cPath=30&products_id=35, Audiolense software: http://www.juicehifi.com/index.html, and Lynx L22 sound card: http://www.lynxstudio.com/product_detail.asp?i=11 in my Windows 7 PC.
Here is a view of my sound system setup. My listening room is approximately 30’L x 16’W x 8’H with no room dampening, mostly hardwood floors and drywall. A very “live” room, with a fairly long RT60. I have the speakers set up on the long side of the room to minimize side wall reflections. I took this pic from the back wall overlooking the couch (i.e. listening position). The couch is about 4 feet from the back wall.
Here is a side view to show how far the speakers are away from the back wall and where the listening position is.
The measurement mic is placed on a mic stand behind the couch with the mic stand feet on foam so any transmission through the floor (the speakers are on Vibrapods – highly recommended) won’t be picked up by the mic. Use a tape measure so that the tip of the mic is at ear level and forms the equilateral triangle with the speakers.
One easy way to measure up is to cut 2 pieces of string that form the equilateral triangle and tape them in the exact same spot on the top of each speaker and hold them taught while moving the mic into position. Note that the mic should be exactly centered between the two speakers at the listening position.
A side note on measurement mics. Regardless of which measurement mic you opt for, ensure that a) it is calibrated and b) you have the calibration file. Have a look at my mic calibration file:
Side note. Notice the mic is calibrated for a “pass band” of 20Hz to 20kHz. Most acoustic measurements will be pass band limited to this range, not only by the microphone, but also by the swept sine wave the measurement software produces and subsequent results through the sound system back to the microphone. This is not an anechoic chamber measurement test to determine the frequency limits of the loudspeaker at 1 watt @ 1 meter. We are measuring the audio chain at the listening position in a real room in order to produce as natural timbre as possible in the pass band. That is our goal.
Side note 2. Timbre is (mostly) the tonal quality of the music reproduced. Ideally speaking, if I was to record the sound of an acoustic guitar in the room and then play it back over the sound system, I am expecting the tonal quality of the reproduced guitar to be as similar as possible to the live guitar. That's what I expect in the studio/control room, I also expect that in my home stereo as well.
Of course the source material and electronics chain plays a factor in timbre for sure. But it is the speaker to room interface that is the weakest link, by far. If you are using measurements as a way to gauge the difference, the speaker to room interface frequency response, at the listening position, has orders of magnitude deviation compared to an amplifier's frequency response for example.
Now that you have the mic setup, let’s turn to the software. Note that Audiolense also creates digital room correction files, but at this time, we are using the free portion of the software to take frequency response measurements at the listening position.
In this seetup screen for a stereo configuration, we are applying a swept sine wave from 20Hz to 24Khz over 10 seconds for each speaker. Be careful when doing this as you don’t want to blast the speakers into oblivion. You would like about a 90db or so measurement at the mic.
Now let’s run the frequency response measurement. Please refer to your sound card manual and Audiolense help file for the finer points of setup and operation. Here is the frequncy response measured at the listening position:
There are several things to infer here. One is the incredible detail of the frequency response measured. The first thing to do is look at a smoothed version (1/3 octave smoothing) that correlates more to what our ear can discriminate between frequencies:
Now how does this frequency response correlate to the B&K house curve mentioned in earlier posts? Side note, the purpose of this exercise is to implement the “target” B&K house curve as closely as possible as it is proven, from a speaker to room interface, to provide the most natural timbre. And as time will tell, it will also produce that elusive depth quality to the sound stage. Audiolense lets you “draw” your own frequency response targets, so I took the image from Figure 5 in http://www.bksv.com/doc/17-197.pdf and drew that exact target curve in Audiolense. Here is what it looks like relative to my measurement, it is the flat curve on top with the high frequency rolloff:
Listening to the sound system correlates to what is being measured on the screen. It is a bit bright sounding, which should come as no surprise as the room my speakers are in have little sound absorption. I seemed to have “voiced” (see Part 2 for voicing) the speakers reasonably well as there are no huge dips or peaks in the low end, save for that 200Hz peak. Also note the different amplitudes from each speaker at the listening position. What we really want is to have each speakers output identical over the frequency range. That will give us a dead center phantom image.
Note the overall shape of the filtered response to the B&K house curve target. Again a bit on the bright side and as a general rule, unless you have a really dampened room, most speakers, relative to the B&K house curve will be a bit bright. Unfortunately this messes with both the timbre and the perceived depth of the sound stage as we will see.
So now what? Ideally I would add dampening material to the room to bring down both the mid to high frequency response to be more in line with B&K house curve and to what my ears perceive. How much dampening? If you crack open any of the acoustic books from F. Alton Everst, it will tell you how to measure RT60 and calculate the number of sabines required to dampen the room at various frequencies. As someone that has been there and done that, it is a lot of work, but is quite rewarding once it is done and matches what you want.
However, with the advent of digital room correction software, in mere minutes, you can generate filters that are the inverse of the measured frequency response, apply it to the target, install the filters in a DSP like ConvolverVST, hosted in a media player like JRiver MC16 and voila:
And the listening result? Near perfect timbre and full depth sound stage.
We will look at this frequency correction result in detail in the next post, including a section on the next step, time domain correction.
Part 1 is here. Thanks for your comments. Before we can measure the frequency response of your sound system at the listening position, we need to configure the speakers to the listening room. These set up steps are required in the quest to hear music the way it was intended to be reproduced – i.e. best effort timbre. This is the first part of a three part process. The three parts are setup, measure, and adjust. Then we iterate, sometimes a few times, sometimes more. It will cost you nothing but a few hours or more of your time moving your speakers and perhaps listening position around your listening room. A tape measure is required.
I was going to dive into acoustics, like in this article: http://www.nonoise.org/quietnet/tcaa/smallrooms.pdf But I thought it would be better to explain a few quick wins that you can easily achieve in your own listening room using a bit of muscle and a tape measure. Of course, these are setup calibration steps in order to establish a baseline for the series of frequency response measurements we are going to perform.
Have a look at this listening room. Actually it is a control room in a recording studio. In fact, the vast majority of control rooms in the world will be a variation of this set up:
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You can find many examples of these setups on the internet, including specifications, plans, golden room ratios, etc. We will come back to that when we look at acoustics. What’s important at this point is:
1. The speakers and the listening position form an equilateral triangle.
2. A best effort attempt at passive room treatments to calibrate the damping, reflections, and RT60 of the room. http://en.wikipedia.org/wiki/Reverberation
3. Best effort attempt at using the tape measure for all measurements, symmetrical or otherwise.
Let’s walk though through this in some detail, but we are going to leave step 2 out for a while.
But first a comment. I take no credit for any of this. These are all public specifications, tried and true, and are generally accepted as industry standard in the pro audio biz. If this is “old hat” to you, just think of it as a quick review of how important it is in the quest to hear music the way it was intended to be reproduced.
An equilateral triangle of the speakers to the listening position is required for proper decoding of the stereo mix. Look at the diagrams above for both the control room and critical listening room. Both are equilateral triangles. In my listening room, my speakers are 9ft apart (center to center) and each speaker is 9ft away from where my ears are located at the listening position. The speakers should be toed in so that they are on axis to your ears in the listening position.
Get out your tape measure. Make sure that whatever equilateral triangle that you end up with that the distance between the speakers and that each speaker to your ears are as exact as possible, down to a ¼ inch tolerance or less if you can do it. This is absolutely critical to ensure you are getting the exact sound stage that was mixed in the control room in the recording studio.
Here is an analogy with respect to sound waves. Ever throw a rock in water and watch the waves it produces? Now throw two rocks in the water, spaced apart (like 3 to 6ft for example) and try to do it so they land in the water at exactly the same time. Really hard to do, but look at the waves produced and when they meet – beautiful symmetry. If the rocks land at different times, then observe the waves produced. The one that landed first will produce a wave sooner than the rock that landed second and when the waveforms mix, it will look distorted, (i.e. loss of symmetry) that is because it is. Quick rule of thumb, sound waves travel 1 foot per millisecond.
Short story. When I was working in a about to be built LEDE studio on the West Coast, Chips Davis used a professional laser distance meter, levels, and transits to layout the design of the studio including measuring the equilateral triangle down to 1/16” tolerance. While I am old school with the tape measure, I see the prices of some of these laser distance meters are down in the $100 to $200 range. So if you spend time measuring, moving the speaker ever so slightly and re-measuring, over and over again – it’s perfectly normal to increment and iterate.
I can’t stress enough how it important that everything is measured and as symmetrical as possible in your listening room. That includes measuring the toe-in of the speakers from the back wall for example so that they are as near a perfect mirror of each other. This is critical to attaining proper timbre, especially related to the perceived depth of the sound stage.
The end result is that your speaker system is calibrated to properly reproduce (i.e. decode) stereo sound. From a listening perspective, each speaker’s sound will arrive at your ears at the same time. This will result in a perfect, none distorted (from a time perspective) representation of the stereo signal. You will hear pinpoint imaging, dead center phantom image, and now in a position to move to the next step of the calibration process.
Before we continue, I know some will ask, how far do I move the speakers into the room from the back wall? Great question and one we will measure, but for a starting point, and avoiding an acoustics conversation, hear is a quick way to “voice” the speaker position in your room and train your ears at the same time.
Play music that has good bass content. If you have sound level meter, like the infamous Radio Shack http://www.maxim-ic.com/images/appnotes/988/DI127Fig04.jpg meter, then select C weighting and slow response and crank up the music to average 85 to 90db (note we will come back to this sound level and why it is important in another post). If you don’t have a sound level meter, no worries, just crank up the sound a bit, but not really loud, we just want to load the room with sound.
Turn your balance control to either left our right so only one speaker is playing. Now go stand beside the speaker and listen to the bass sound. Listen to how even the bass sounds as the notes go from high to low and vice versa. Does the bass sound louder on some notes and less on others? If so, start moving the speaker slowly forward while listening. For really trained ears, this is like blowing air into a Coke bottle and hearing the resonance. That’s what we are doing. We are trying to find the sweet spot where all of the bass notes sound even up and down the scale.
If you can’t hear the difference, no worries. Try moving the speaker against or as close to the back wall as possible. It is likely to sound boxy, or too much bass. Now move the speaker several feet from the back wall and listen again – the bass response should be considerably different. It may be that most of the bass seems to have disappeared. Somewhere between the two positions is the best position for the speaker based on your specific room ratios. Patience and practice will assist in finding the sweet spot.
Now turn the balance control to the other speaker and move the speaker the same distance from the rear wall that you had moved the other speaker from. It should sound the same in the bass region. Use a tape measure to get it exact. Now turn the balance control to the center and listen again. Bass notes sound even through the scale? Does the balance of bass to mids, to highs sound ok? Use your ears, they are wonderful measuring devices. Congrats, you just voiced your speaker to room interface without having a PHD in acoustics or breaking out the measuring equipment. Remember this is a starting point or baseline in order to continue the calibration process.
Now that you have located the sweet spot, make the measurements exact using the tape measure to form that equalateral triangle. Take the time to get it within a ¼” tolerance.
I am a bit reluctant to get into room treatments and acoustics until we take some measurements. The reality is that you have the listening room you have. You could work out the room modes with a room mode calculator like http://www.mcsquared.com/metricmodes.htm and you would do well to read the reference links at the bottom of: http://en.wikipedia.org/wiki/Resonant_room_modes You could also check to see if your room falls into the gold room ratios that are in the slides I referenced earlier. You will notice in the article that there are different types of rooms from the LEDE to RFZ to ESS. My own room falls into the latter ESS category. You can also look at this speaker set up guide: http://www.cardas.com/pdf/roomsetup.pdf
We are at a point where we have a best effort speaker to room setup and calibrated to a well-known standard (i.e. equilateral triangle). Now we have a baseline in which we can start taking frequency response measurements. In my next post, I will start taking measurements of this setup and we will see how close I voiced my speaker setup in the bass frequencies – remember they should be as evenly distributed as possible. I will get into a bit of room acoustics and basic room treatments if the measurements warrant it.
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I love music, any kind of music really. As a former recording/mixing engineer/producer for 8 years, and lifetime audio freak, I had the privilege to record, mix, and master a wide variety of music. In this introductory post, we will look at the most important quality of reproducing music called, "timbre". Over a series of posts, the goal is to calibrate your sound system to be the most accurate reproducer of music for your ultimate listening pleasure :-)
In Wikipedia’s definition of timbre, you will see, aside from the technical definition, “In psychoacoustics, timbre is also called tone quality and tone color.” Tone quality is critically important in the reproduction of recorded music.
If you have ever heard live music, (e.g. piano, acoustic guitar, horns, strings, drums, etc.) then you may remember how it sounded. You may also remember when you went home and listened to something similar on your stereo that it did not have the same “tone quality”. Why?
Well, it so happens that another group of folks were also wondering this and produced this outstanding short article on, “Relevant loudspeaker tests in studios in Hi-Fi dealers' demo rooms in the home etc.” Of very particular importance is the frequency response curve in Figure 5. We will come back to that a bit later.
From the article abstract, “The "sound" of a Hi-Fi set is to a great extent room dependent. Very often, the final result is determined by the room rather than by the actual equipment. Fortunately, these influences may readily be measured.”
What the article is describing is musical timbre or tone quality. Unfortunately, the reality is that the tone quality reproduced by your sound system is highly dependent on your listening room. Before becoming a recording engineer, I was in electronics engineering world and as a hobby, built a great deal of speakers, amplifiers and preamps (still do). I also got into room acoustics and managed to get my hands on this wonderful device that revolutionized audio measurement techniques.
The TEF stands for time, energy and frequency. Very quickly you could analyze a room in 3D and determine the rooms “tonal quality” for sound reproduction. Based on that, you could treat the room with “Tube Traps” for bass frequency tuning, absorption materials for dampening overly live rooms, and “diffuser panels” to prevent slap echoes, but not overly dampen the room. I bought every possible book on recording and control room design and room tuning. I will provide a resource list later for those interested.
I had the privilege to observe Chips Davis design and build two multi-million dollar recording studios and control rooms from scratch using his infamous Live End Dead End (LEDE) room design. I then went on to “treat” several recording studios, controls rooms, critical listening rooms at audio dealers, and several private critical listening rooms using the TEF computer and lessons I learned from Chips plus the reference books.
My point in saying all of this is to pass on to you my learning’s to benefit you in your quest for the most tonally accurate sound reproduction system you can achieve with your existing equipment. No, I am not going to suggest you rip up your room or spend thousands or tens of thousands of dollars on acoustical measurement equipment and room treatments. What I am suggesting is that with a few key considerations, and a few bucks, you can make dramatic improvements to the tonal quality of your existing sound system.
Let’s get back to timbre and that B&K article, specifically Figure 5, “Optimum curve for hi fi equipment measured in the actual listening room.” Figure 5 is the key to tonal quality. That curve is the frequency response measured at the listening position. If your sound system measures close to this curve, especially the roll-off, then congratulations, you have achieved tonal perfection! Once you have heard a sound system that is calibrated to this curve, then you will understand exactly what I mean. Everything sounds “right” and all of a sudden the depth soundstage magically appears.
There is good reason for this curve, affectionately called the B&K house curve. In the recording studio world, in the control room, there will most always be a set of speakers that are tuned or calibrated to the B&K house curve. Why? Because it most accurately reproduces instruments that sound tonally correct. I.e. it has the best timbre. Additionally, when mixing engineers move from one studio to the next and listen to their mix downs, with this curve, it will have the same tone quality it had in the previous studio. Consistency is the key.
My wife, who is not an audiophile and puts ups with my tape measures and swept sine waves once commented, “I was in the garage and even there it sounded like someone is playing the piano in our living room.” That is near perfect timbre.
So the first step in understanding whether your sound system is tonally correct or at least as best as it can be, is to measure the frequency response at the listening position in your listening room and compare it to the B&K house curve. In my next post, I will show you how to do that without breaking the bank.
I listen in a home office which has my music server and stereo, and also a PC for work/pleasure. Typically I'm at the computer and listening to music from the audio system.
Recently seemed that I'd lost volume (3-6db) in the stereo. Was turning the volume up a couple of notches more than I'm used to.
Couldn't figure out the problem, and then yesterday had to do some serious maintenance on the PC (reformat and rebuild the main C drive contents).
Anyway, this obviously entailed several shutdowns and reboots of the PC. And guess what? Every time the power on the PC went off, the volume of the music playing went up and clarity of sound improved. Every time I pressed the power button to turn on the PC again, the Volume/SQ decreased, and stayed that way until the next time the PC was turned off.
Immediately had a small panic, and started thinking about all the possible expensive solutions: Power regenerator for the Audio system, noise filters on the power lines, installing a separate circuit just for the audio, etc.
Then I talked to 2 friends who are electricians. They suggested 2 likely possibilities:
a)Power suck caused by some problem with the PS of the PC - the PC on its own, they said, doesn't usually draw enough current on a continuous basis to have that kind of effect(again, it wasn't just on PC startup, but for as long as the PC was on).
b)Noise in the system introduced by the PC. Either general electrical/circuit noise, or some kind of interference transferred over to the sound system. Said it may not be a "power drop", but just lower apparent volume caused by noise in the system. Asked if the PC was connected to the stereo. I said no. They suggested, among other things, using an extension chord and plugging the PC in on a totally different circuit in another room to see if that made a difference.
But when I got home, I suddenly realized that the PC WAS directly hooked up to the stereo. I'd recorded an LP about 10 days before,and had listened to and edited the results on my PC, and to the editing played directly from the PC through to the stereo. I'd left in place the cables the went from the analogue out of my PC to the line in on my preamp.
Disconnected the pair of analogue cables...and the problem stopped.
I still don't understand exactly why the PC/pre connection would cause this, but relate the incident here b/c it may help others. Apparently the PC was sending out a signal over the analogue out, even when I wasn't "playing" anything, and even tough that set of "outs" wasn't chosen as the default output.
Computers are noise/interference generators, and you definitely want noise and electrical isolation between them and your sound system if you can manage it.
RMAF is the mother of all of the regional audio shows. While CES is (supposedly) for dealers and media, RMAF is all about is, the consumer. Which makes it more than a little awesome. And given how popular it (and audio shows generally) has become, it's also a little bit huge.
I remember last year, my first show. It was an exhausting 2 and a half days. I remember getting prepped. I had a new iPad -- I was going to take notes on every room. I had my camera -- I was going to take dozens of pics in every room. I had music, both CDs and a memory stick, and I was going play the same damn tracks on every system I could. I was going work the show, baby.
That lasted until lunch time on Saturday, about halfway through the show until I was toast. Total overload. Everything started blurring together and then, suddenly, I was leaving Denver.
This year, its going to be different. Yeah, sure it is.
This year, I'm still taking my iPad -- but this time, it's for Netflix whenever I feel like chilling out. I'm taking a camera -- and for sure, I'll be snapping shots everywhere I go. And yeah, I'm also taking music for the systems that warrant it. But I'm not going to go nuts. This year, I'm actually gonna have some fun. LOL.
But I'm open to a little guidance. Got something you want me to chase down? Something you want to see or read more about? Drop me a note and I'll queue it up. I'm gonna be there for the full shindig, so hopefully I can slot it in.
I'm gonna want to check out a bunch of DACs. I've heard the best (so they say), so now it's time to hear the rest. I know at least one exhibitor will have the elusive Alpha USB in play, so I'm gonna go hunt that sucker down. I'm also gonna grab some time on dCS and Wavelength. MSB if I can find it.
I'm also planning to check out some vinyl stuff. Jeff Catalano always has a great sounding room, so I'll stop in and sweat off a few pounds in that sauna he calls a demo room (there's really no wonder why he's a skinny rail of a man). Dr Feickert may have some new stuff on display, too, who knows?
The speaker I'm most curious about? The KEF Blade. Been hearing some great things about this speaker -- time to put my ears on it. And my tongue. You know. "Full sensory" and all that.
I'm also down for the Dean Peer concert, the CA meet-and-greet on Friday, I'm going to try at least 2 seminars. I've always wanted to hear John Atkinson's speaker measurements talk and the future of high-res digital sounds good too.
But that's it. So, obviously I'm going to have a ton of time on my hands. Um, yeah. But anyway, feel free to guide me. Anything I'm missing that's hot on your list of must-see-TV?
Rational Audio....a subjectivist journey.
I began audio as a rational consumer or so I thought. I didn't want to spend money that didn't provide additional performance. Mainly because I didn't have much to spend. I wondered for instance why those Magnepan speakers cost so much when they didn't go down below 50 hz and only went up to 15 khz. So many speakers went lower and higher with less power for less money. With my first real job came a chance to buy a good stereo. I purchased a receiver of modest power, speakers that sounded good from what I had heard, a turntable and cassette deck. Still have the receiver that functions perfectly 30 years later. The tape deck functioned until a couple years ago. The rest was sold over the years. Most of my 'knowledge' was from reading Stereo Review and Audio.
As fortune would have it I later worked with someone owning Magnepan speakers, driven by a G.A.S amp controlled by an Audio Research pre-amp. No it didn't play as loud as my speakers, didn't sound as warm(I of course now know my speakers were overblown and poorly controlled in the low end), but somehow it was clearly far more musical.This system was just flat more enjoyable. I learned about a few more brands and pieces of high end audio equipment that wasn't exactly mainstream from this coworker. Later I took to reading Stereophile and the very strange Absolute Sound at the local library.
Specs couldn't be relied upon to figure out which pieces of equipment sounded the best. Plus the soon to be released CD despite great specs far beyond any LP system clearly had some problems. It just didn't sound fun to listen to like a fine analog rig. I fell under the spell of subjectivists. The ear was the final arbiter of worth. The funny Absolute Sound discussing the problems with digital sound and which wire was the best didn't seem so funny anymore. A newspaper ad listed some Maggie 2C's at a price I could afford along with a Carver Receiver. I eventually made a deal for those as my receiver didn't have enough power for the Maggies and the Carver did. Funny that I got that Carver with the Maggies. Super specs, lots of power, an FM section that was quite remarkable in many ways. Yet it did not sound that great either. Not like my buddy's G.A.S. amp.
Not long thereafter a pair of really cheap Acoustat Two's were in the local trading paper. I had read of them in the Absolute Sound, and these were honest to god mythical electrostats. I was immediately smitten by the sound (and prefer electrostats to this day), but wondered if my Carver receiver would play them. The owner said no way. I went back with the Carver to see. I must say it played them quite admirably. The Acoustat owner found it hard to believe. So I ended up with the Acoustats. The Carver really had power to play this difficult load though the sound quality could be better. In time I found a McIntosh 752 I could afford. Though less powerful than the Carver it played the Acoustats well enough and sounded far nicer. The Mac owner threw in some nice speaker cable which I thought helped as well.
So now I had a receiver and some Maggies I wasn't using. Put an ad in the paper and eventually sold them to someone that would become a good friend. He also knew several other audiophiles in my town. He didn't buy the receiver however. But getting to know other audiophiles was important in getting to hear other serious highly enjoyable sound systems. I was able to hear how various systems did things well though none did everything well. Hearing horns, LS3/5a speakers and speakers like Thiels.
Skipping ahead rather than detailing every step up I made, in time I owned Quad ESL63's which would eventually be driven by tubes. Still making decisions subjectively upon my opinion of the sound of CDP's, DAC's, pre and power amps, cabling all of it. It still didn't sit easy with me however. That so much seemed unexplainable. Some of the equipment made large improvements in sound quality. These seemed magical. All good hifi rigs of course should seem magical. Only I didn't really believe in magic. In time I went to the bother of taking a junior college program in industrial electronics just to learn more about all this stuff. I earned a two year degree in electronics. I had seen too many explanations in high end mags that simply were wrong though espoused as if from some authoritative understanding. I wanted to know how this really worked.
Prior to this high end equipment seemed mysterious and magical. Special designers having figured out the mysteries of power amps, and component selection magic made musical high end equipment, while mass market stuff was like a paint by numbers enterprise designed by specs selling inexpensively while sounding worse. When I learned basic electronics it began to loose its mystery. As I applied what I had learned to the particulars of audio more mystery was lost. Not to say all such equipment was a farce or bilking consumers. Much of it was made to a much higher standard, and truly provided much better sound quality than mass market items. Even so much of the marketing and magazine writing really was so much bunk. Claims for what made one item better than another was actually no explanation or was simply wrong headed.
I did begin to apply my new electronics knowledge to modding equipment. Replacing components with better quality components which did seem to improve sound. My Quads were driven by tube amps by then. CD transports driving DACs had improved enough I thought them musical enough to replace LPs. I found pre-amps unneeded if your DAC is the source. I built my own switched resistor passive pre-amps eventually. One of my friends and I improved components in the VTL tube amps he and I owned, things like better caps (MIT's), and resistors (Vishays). Then we rewired them from Ultralinear to triode connection. Not to mention buying good sounding replacement tubes. At this point I learned enough basic electronics to alter equipment, understand how the circuits worked, yet made all my decisions subjectively as to whether a given change of circuitry or componentry was a step forward or not.
After these mods a few of my friends thought the trioded, upgraded, modded VTL was the most musical sounding amp they had heard. We took them over to their houses to try them out on a number of different systems. It seemed to convey rhythm, resolve space and fine detail better than other amps while being highly musical. Following words and music was simply easier. I had become addicted to regularly improving the sound of those fine tube amps. I at that time didn't know of any likely useful changes to make. I could think of a few that would be highly complex and expensive. I began to wonder, “how much better could it get?” I wondered did my amps at that time convey 99% of the music in the input signal or only 50%. Was there little left to gain or much more to be coaxed out of it?
I also had a Spectral DMA50 at that time. One of the few really good sounding transistor amps I had heard. Subjectively I would say it was 60% as good as the VTL at that time. An idea began to form as a way to figure out how much was lost in the VTL from input to output. The Spectral was good enough sounding to make good judgments in comparing upstream changes. What if I loaded the VTL with a power resistor at the output, then used high quality resistors to step down the voltage so the resulting signal was exactly unity gain. Then I fed that into the Spectral and listened to it. If the VTL was perfect straight wire with gain, feeding the Spectral I should hear no difference with it between my DAC and the Spectral amp. If the VTL was passing 50% of the information in the input signal, then the Spectral was good enough I could hear the loss in quality and musicality. I would have an idea how much room for improvement there was.
I did that experiment. The results were quite obvious, and completely unexpected. With a VTL between the DAC and Spectral power amp the sound out of my Quads simply sounded like the VTL. It was spacious, liquid, naturally smooth sounding, with glowing inner detail, and a highly musical quality. I was hearing exactly what the VTL always seemed to sound like. How could this be? I knew the Spectral lost some resolution and fine detail yet I was hearing that with the Spectral driving the speakers. In time I thought the sound was a little leaner, and the treble a little recessed vs the VTL, but only a little. The basic quality was still of a highly musical triode amp. I even quickly knew why. I knew the VTL because of the odd impedance of the Quads had its output impedance react with the speaker to give a 1.25 dB bump centered around 50 hz and covering nearly two octaves and the transformer from measurements I had done would have a rising response just above 20khz, but it was wide enough it lifted the last audible octave about .5 a dB. The Spectral was pretty much unaffected by the load of the Quads.
I decided to reverse positions. I loaded the output of the Spectral with power resistors and attenuated the result to achieve unity gain and fed it into the VTL. I could not hear any effect of the Spectral being in or out of the circuit. I listened for several days and put the Spectral in and out a number of times. Sounded the same either way. The Spectral should be straight wire with gain. It had DC-1 mhz bandwidth, a very high slew rate, S/N around 90 dB, very low distortion and excellent channel separation. It should be audibly invisible.
So not an answer I anticipated. The only reasonable conclusion was the Spectral did little if anything to harm the signal. While the VTL for all of its apparent superior sound was subjectively superior because it colored the sound in a pleasing manner. No other idea made sense.
I tried this same experiment with a few more quality transistor amps. No others quite matched the Spectral for being invisible. Some came pretty close some were surprisingly audible as being brittle sounding or having misty grainy highs. All when driven by the VTL however sounded at least 60% or more like the VTL. You would hear the qualities of the VTL overlaid with whatever inadequacies were in the various solid state amps.
Over a few years I had argued foolishly it now seems with people like James Johnston (known as JJ) on various internet forums or newsgroups. I eventually read a couple of the textbooks on psycho-acoustics he recommended. Those have plenty of information useful in home audio. Some things are readily explainable in scientifically proven terms. JJ wouldn't claim all solid state amps sound the same as he knows the basic specs aren't enough. But specs well applied are usable. Much of subjectivist audio I think has gotten out of hand . Not all audible phenomena can yet be fully explained, but quite a lot of it can. Much of this knowledge is regularly ignored by people who should know better. I think we could get further along and get better sound for less money by using this knowledge rather than ridiculing it.
Greetings all, my name is Gary, and I like to listen to good music. Good meaning in the sense of a quality recording, not necessarily a specific genre or specific performer. I like listen to a variety of music, from classic rock, acoustic blues, jazz to classical, and have been know to cue up Marilyn Manson on my walk home from work (yes, I did that the other day after buying my B&W C5 headphones).
As a father with a 7 year old daughter, and a 4 year old son with special needs, I do not (yet) have the resources to devote to a listening room/area in our three bedroom condo. I can not count the number of times my Boston Acoustic VR-M50 bookshelf speakers have been pushed over onto the floor. So I will not be buying new speakers anytime soon.
So is it possible to have a computer based, audiophile quality system on a budget? This blog will detail my experiences. My first blog entry will be on budgeting and priorities, from my expected goals, to the money I have wasted, as well as the wife and kid acceptance factors. Look for it soon!