REW vs Acourate?

[tboooe]

Hi guys I just started using REW and have been very impressed with the improvements I have experienced so of course I am looking to see if I can do even better. In reading about Acourate it seems it also auto correct for phase and it uses FIR versus IIR filters (to be honest I have no idea what this means). Anyway, curious if people have tried both and felt Acourate was better and worth the money over REW.

[Fitzcaraldo215]

Hi guys I just started using REW and have been very impressed with the improvements I have experienced so of course I am looking to see if I can do even better. In reading about Acourate it seems it also auto correct for phase and it uses FIR versus IIR filters (to be honest I have no idea what this means). Anyway, curious if people have tried both and felt Acourate was better and worth the money over REW.

Apples and oranges. REW is only a measurement tool. Acourate, like several other DSP EQ packages, is a comprehensive DSP room correction tool that first takes measurements in order to do its thing. It can apply those corrections on the fly during playback. REW cannot.

 

What would you do with the measured results of REW, since it cannot do anything for you during actual music playback?

 

Me, I use Dirac Live myself. It is much less complex than either of the above, yet is still quite advanced in measurement and room correction during playback. My results are terrific, and the learning curve is quite simple.

[tboooe]

Apples and oranges. REW is only a measurement tool. Acourate, like several other DSP EQ packages, is a comprehensive DSP room correction tool that first takes measurements in order to do its thing. It can apply those corrections on the fly during playback. REW cannot.

 

What would you do with the measured results of REW, since it cannot do anything for you during actual music playback?

 

Me, I use Dirac Live myself. It is much less complex than either of the above, yet is still quite advanced in measurement and room correction during playback. My results are terrific, and the learning curve is quite simple.

Thank you for the reply. I output the corrections from REW as mono wav files and use HQPlayer convolution engine. I will be doing the same with the output from Acourate.

[Keith_W]

Hi guys I just started using REW and have been very impressed with the improvements I have experienced so of course I am looking to see if I can do even better. In reading about Acourate it seems it also auto correct for phase and it uses FIR versus IIR filters (to be honest I have no idea what this means). Anyway, curious if people have tried both and felt Acourate was better and worth the money over REW.

 

Fitzcaraldo answered the main thrust of your question. REW is free, and great for telling you what's wrong. But it doesn't always provide the tools you need to fix it. Even though I have Acourate, I still use REW - because it is faster and simpler. If all I want is to take a quick reading, REW is all that I need.

The difference between FIR (Finite Impulse Response) and IIR (Infinite Impulse Response) has to do with the mathematical design of the filters. If an impulse is introduced to the signal, the IIR filter may oscillate and ring to infinity, although in reality it usually dies down after a few cycles. The advantage of an IIR is that less computing power is required. In contrast, a FIR filter will ring for a finite period after the impulse. The disadvantage is that it might "pre-ring" (i.e. generate ringing before the impulse!) and it requires more computing power. Acourate has a pre-ringing compensation which is very effective at eliminating this.

 

Acourate doesn't necessarily auto-correct anything. It has macros which has some automation, but if you want you could also run everything in manual mode. The macros themselves are already pretty daunting if you don't have a good manual (like mitchco's ebook) with you. But manual mode is on another level of difficulty. You might want to use manual mode if you want to try some of the advanced functions of Acourate.

[tboooe]

thank you @Keith_W, I appreciate the response. All the extra tools in Acourate are cool but bottom line does it allow better sounding results? Since you have REW can you say a few words regarding sound quality?

[Keith_W]

@tboooe I can't comment on the sound quality of REW vs. Acourate. This is because I have not tried to generate filters using REW. As I have said to you before, it is not so much the program that makes a difference to the SQ - it is how you use it. Much like how Sebastian Vettel will go around the track faster in my Volkswagen than I will in in his Ferrari.

 

Acourate will allow you to get closer to the ideal result. It tells you more, and lets you do more. If you understand what it is telling you and learn how to drive it well, ultimately the sound quality will be better. If you don't know what you are doing, or misinterpret the results, or fail to follow the correct workflow, then ALL DSP programs will provide awful sound. A novice using Acourate will get worse results than a pro using REW.

[tboooe]

A novice using Acourate will get worse results than a pro using REW.

Unfortunately I am a novice at both!!!! Seriously, thank you for the input. I will ultimately get Acourate because I am curious to learn more about digital room correction.

 

As for Vettel, if he doesnt keep his cool you may just go faster than him in any car!!! (just a little F1 humor!)

[SwissBear]

Hi tboooe,

 

I do not quite share the comments of Keith_W regarding Acourate: this product is, in my opinion, very versatile and can accommodate the needs/expectations of the beginner as well as those of the expert. Just follow step by step the tutorial of Mitch and you will be safe. Do not try to innovate with the settings; just keep the default ones and you will produce very good corrections. Also, Uli, the developer of Acourate, is very helpful and friendly.

 

It might be worth noting that the corrections brought by Acourate are a little more 'micro-managed' than the ones brought by REW. In the amplitude domain, here is a comparison of two impulses, one produced by Acourate (green and red) and the other one by REW/rePhase (black and blue). You will notice that the Acourate impulse is providing more active correction than REW. This can be adjusted of course.

 

The same is true in the time domain, but I leave up to you to discover that.

Good choice for Acourate, and you can always keep REW and develop your knowledge in the time domain to master rePhase and compare which corrections you prefer

[Keith_W]

I'm not quite sure what you disagree with me about, Swissbear. Because I agree with your comments.

[SwissBear]

Hi Keith,

 

I probably misunderstood the statement which was quoted by tboooe. Glad we are on the same page

[tboooe]

Thank you @SwissBear, I am definitely interested in the time domain corrections. I have a bit of problem in the 60-100hz range of the combined response. It seems I have a bit of a phase issue of the combined response of both the speakers in this range. Individually, the speakers play in those freqs (60-100hz) just fine but when I play both speakers I get a combined output that is less in SPL than the individual speakers. See below. The red line is combined, blue is left and green is right. Is this something Acouratee can fix?

 

[SwissBear]

Not sure. Phase issues are difficult. But this is definitely worth a trial

[tboooe]

BTW, I know Acourate can do time domain corrections if I have an active cross over system but in my case, since I am not using the Acourate cross overs, I believe I cant do time domain corrections in Acourate correct?

[Keith_W]

That is correct. You need control of each individual driver in order to do time domain corrections.

[SwissBear]

@tboooe,

 

Acourate allows you to make time domain corrections even if you do not change the passive cross-overs of your speakers for active cross-overs.

Here are the changes I made to my speakers in this field, without touching anything to the HW.

 

The impulses have considerably been improved by Acourate:

and the phase has also been improved:

[tboooe]

@tboooe,

 

Acourate allows you to make time domain corrections even if you do not change the passive cross-overs of your speakers for active cross-overs.

 

thank you...can you please explain how you make time domain changes?

[SwissBear]

thank you...can you please explain how you make time domain changes?

You have nothing to do. This is part of the standard Acourate correction process.

[tboooe]

Ok thank you. I was a little confused because it sounded like the user could somehow manually adjust time domain.

 

The graphs you posted are very impressive. Looks like I will buy Acourate!

[SwissBear]

The only thing you have to do is, when generating the correction impulses, to decide the width of the window you want to use to correct the excess phase of the system. This is part of Macro 4.

 

You can refer to the web site of Acourate (http://www.audiovero.de/en/acourate.php), and look at the description of the product:

You will notice that the possibility to create digital (active) cross-overs is part of the 'Further functions' paragraph, whereas the Timing errors correction via phase correction is part of the 'Solution', ie standard features.

[dallasjustice]

Acourate is a suite of tools intended to help create the best filters for both time and amplitude corrections.

 

REW is mostly a measurement tool. Of course, you can generate EQ filters with REW. But it's not able to generate time domain corrections.

 

The only reason you might prefer REW over Acourate is that it's free. If you want a free tool which can generate filters most like Acourate, then RePhase is your best bet.

 

There's a great thread someone on the Jriver forum regarding RePhase. It's basically a comprehensive guide.

 

Acourate takes some learning. I think RePhase is even more complex based on my limited experience with it.

 

You haven't described how you hope to use the DSP filters. IMO, FIR filters are always superior to IIR ones, IF you take care when creating them. If you plan on using digital crossovers and you have sufficient computer power, it's rare for a minimum phase filter to outperform a linear phase one.

 

Michael.

[SwissBear]

You haven't described how you hope to use the DSP filters. IMO, FIR filters are always superior to IIR ones, IF you take care when creating them. If you plan on using digital crossovers and you have sufficient computer power, it's rare for a minimum phase filter to outperform a linear phase one.

 

Hi Michael,

 

Could you please elaborate on this ?

 

Here are the links to rePhase:

- tutorial (Guide to Speaker/Room Correction Using Freeware and JRiver)

- forum (rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool - Page 130 - diyAudio)

 

I do not have any experience replacing passive cross-overs with active ones. But my experience using rePhase as part of a room correction suite with REW as an alternative to Acourate has taught me that aiming at minimum phase corrections was the only way to get rid of pre-ringing and that linear filters were a significant source of pre-ringing. Here is an illustration of this: rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool - Page 130 - diyAudio

[vladimirb0b]

REW is mostly a measurement tool. Of course, you can generate EQ filters with REW. But it's not able to generate time domain corrections.

But you can still output an impulse to turn into a convolution filter with DRC... Correct?

[tboooe]

But you can still output an impulse to turn into a convolution filter with DRC... Correct?

 

Yes absolutely. I generated mono wav files to use with HQP and JRMC convolution. Sounds great though I am looking for more improvement with Acourate.

[dallasjustice]

But you can still output an impulse to turn into a convolution filter with DRC... Correct?

 

REW can only produce EQ filters (e.g. Wav files). It is not designed to correct time domain as well. Time and amplitude are related and amplitude does affect time but REW is primarily designed to generate EQ filter to address minimum phase room ringing. This is the primary value with any DSP software. However, some folks believe that improved step response is also audible and can improve enjoyment. I agree with them. But this is a debated issue. I bet John Mulcahy would argue otherwise. He's pretty smart so I wouldn't debate him on the issue. :-)

[SwissBear]

I bet John Mulcahy would argue otherwise. He's pretty smart so I wouldn't debate him on the issue. :-)

 

John has agreed to develop an interface between REW and rePhase (rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool - Page 128 - diyAudio). This might be the sign that he does not disagree with the interest of making time domain corrections as well