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Nyal Mellor

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  1. Personally I don't think it is possible to get better results than using an RS20i or Altitude by cobbling something together with a HTPC. There's a big problem with spatial audio and HTPC, as you will have to send a bitstream from the HTPC to the pre-pro, and you can't do any processing in the HTPC on a bitstream. That means no room correction or signal manipulation. Even if Atmos or DTS.X decoders were available for the HTPC I do not think it would be worth it, as my experiment showed.
  2. DEQX? Check out the HDP-4 and HDP-5. They have linear phase driver correction and crossovers. Sound quality is very good. Check out the stereophile review of the PreMATE
  3. Been there, done that http://www.acousticfrontiers.com/201366how-to-replace-your-home-theater-pre-pro-with-a-htpc/. IMO too many issues with it...now using a Datasat
  4. I'm selling our demo ExaSound E28. MSRP $3849, price $2699. It's a MK1 unit sent back to factory at end of 2015 for a refresh and overhaul. It's been upgraded to MK2 status with the exception of the 12V trigger. It's unopened and unused since the return from the factory, as you can see from the photo. ExaSound did a very comprehensive job of the upgrade. It has new face plate, new feet, new packaging. Almost a new unit! This one has the miniXLR outputs and the Femtoclock upgrade. Includes factory packaging, cabling (power, USB) and remote. Any Q's call Nyal 415 524 8741. Sales tax payable in California.
  5. ATC50 and the Devialet 200 are a great match. We have that combo in our SF Bay Area showroom. I haven't found anything that sounds better driving the ATC that the Devialet Sent from my iPhone using Tapatalk
  6. This one is easy. Devialet D120 or D200! Sent from my iPhone using Tapatalk
  7. I did a pretty comprehensive evaluation of a HTPC as pre-pro. It can sound very good but is a PITA to set up, difficult to properly calibrate and challenging to maintain. And I'm not saying that because I am technically inept or challenged. The JRiver (what you would likely use) documentation is poor and all over the place, getting room EQ wizard signals through JRiver is messy, trying to calibrate the video is difficult because of challenges of using standard calibration discs (difficulty in selecting individual chapters on calibration discs) and impossibility of using external pattern generators. Then there are the constant Windows updates, anti-virus updates, JRiver updates, driver updates...all of which can break things. This documents my experience: How to replace your home theater pre-pro with a HTPC! - Acoustic Frontiers The main limitation of a HTPC as pre-pro is the near impossibility of getting external sources onto it. I do not know of anyone who has built one that integrates audio or video from external sources like cable boxes or game consoles. IMO unless you have esoteric requirements I'm generally pointing people towards either a K-Scape server (for movies) or an Aurender server (for music). Both have come down in price to pretty much the same price as a high end fanless HTPC build ($2500). Of course HTPC still has value if you want to do multi-channel music. At this juncture I would only advise a HTPC for true geeks with specific needs. Anyone who wants something the family can use, then that is a pre-pro/AVR! There are a few pre-pros with Dirac and more coming soon (AudioControl are releasing some at CEDIA EXPO). The Emotiva sounds good but is limited to 7.1. I had the opportunity to calibrate one and thought it was pretty decent, except transferring the Dirac filters from the PC software application took a really long time. We have the Datasat RS20i in our showroom which is obviously very good but out of financial reach for most. Of course this is just my opinion based on my experiences. Others will have different opinions. BTW if you want an Exasound E28 we are selling one on A'gon at present.
  8. Maybe CCCLAPP but I bet it's quicker using acoustic measurements...
  9. Hey Jim The 47HZ is the 2nd length mode and it only nulls 25% and 75% along the room's length dimensions. Preferably you do not want to sit in a null for any of the major widely spaced room mode (i.e. those below 120Hz or so), although of course the left to right width mode is hard to avoid if you also want to maintain symmetry in the room in terms of speaker placement relative to side walls. The real trick is balancing speaker and listener interaction with room modes, listener to speaker distance and speaker boundary interference. Nyal
  10. Here's the graph showing the before and after of dallasjustice's speaker placement. The frequency resolution is 1/12th octave. The placement shown was a result of the following: 1) analyzing the 'before' graph to identify root causes of the issues. In this case there is a room mode related peak at ~25Hz another at ~47Hz and a speaker boundary interference related null at ~37Hz. There is no modal support for frequencies between 25Hz and 47Hz which is another cause of the frequency response null or 'droop'. The room mode frequencies and distribution were calculated using a proprietary room mode calculator. In more complex non-rectangular rooms a boundary element model is used to predict modal frequencies and distribution. 2) determining suitable placement to minimize coupling of speakers to the room modes and minimizing speaker boundary interference. In this case we were lucky in that the null for the 47Hz mode was around 5ft from the back wall, the placement of the speakers in this null would also result in coincidence of the speaker boundary interference null (caused by the front wall behind the speakers) at this frequency, therefore further reducing its effects. Blue is before, green is after. All of this is before any room treatment. Acoustic treatment will help smooth the modal issues about ~60HZ. EQ will be used to further flatten things out below this. The real objective of this exercise was to set things up so that frequency response was as flat as possible below 60Hz so that acoustic treatment could deal with the remaining above 60Hz issues. It's obviously very difficult to EQ a null such as the 37Hz one, so that's why speaker placement is important, as this exercise shows.
  11. Hi Mitch The book is called Sound Reproduction by Floyd Toole, get a copy it's really THE summary of small room acoustics!
  12. Hi Mitch Actually the B&K house curve was one of the things I disagreed with. Just because there is correlation doesn't mean there is causality. I think there are many more relevant controlled listening test results to evaluate such as those covered in the Toole book that give better insight than the B&K paper. Re the use of waterfalls; Jeff and I prefer to use the 2D spectograms as shown in the low frequency decay section. It's the same data just presented in what I find to be an easier to read format. I understand your point about preferring a longer decay time, that's ok, each of us has their subjective preference. T60, like I said in the white paper, doesn't tell us much more than if a room is too live or too dead anyway. Much more instructive with reference to reflected energy in the room to look at an ETC and specifically one third octave filtered versions of that or a one third octave smoothed waterfall or spectogram. Thanks for your constructive critique, I did make a call early on that the white paper should not cover the how. There are just too many variables for someone like me (someone who does room design professionally) to be able to write a generic article on 'how to treat your room' and think that I had done a good job from an engineering perspective...maybe I could write a book, since there are so many nuances and if/then issues with the how to treat a room question...if you want simple answers better to get that from the acoustic treatment manufacturers. Thanks for writing your series of articles. We need more people who understand the importance of the room to sound reproduction! Nyal
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