DSP speaker/room correction

[esldude]

What I would like to be able to do, within OS X, is plug in a microphone, run some software, and generate one or a series of correction plug-ins that I could use with Audirvana, without having to get a Ph.D. in applications of Fourier analysis.

 

This is another example of how such a forum would useful. The amount of complication of the various DSP approaches varies from not too bad to as you say needing knowledge of Fourier analysis. Some do more than others. Some do only 500 hz and down as that is where the largest room problems are and most speakers of quality are relatively well behaved above that. All things that could be shared on a DSP forum. Then easily found in one location.

[wgscott]

I, on the other hand, think we could really benefit from having a sub-forum dedicated to digital signal processing.

[Hipper]

Do you have the dac in the DSP as a crossover also? Looking for options to combine DAC/DSP/Crossover in one box.

 

I know of TACT, which I think are no longer made, DEQX, and the Behringer DCX 2496.

 

The latter was used by VMPS for an active crossovers option on their later speakers. The designer, the late Brian Cheney, said that even though this set up would involve a double conversion (the DAC, then to the DCX's ADC and, after the DSP/crossover work, the DCX's DAC and on to the amps) he found the DCX's conversions were neutral and would show through any colouring of the original DAC.

 

I use a Behringer DEQ2496 placed between my CD Transport and DAC and operating only in digital (my DAC has a volume control). The DEQ does not have crossovers though.

 

All these boxes require a lot of learning to get the best out of them and that presumably is why they aren't more commonly used - that and the price of TACT and DEQX.

 

And I too like the idea of DSP forum. There seems to be an interest in it on here as the front page occasionally has reviews of such software.

[Audio_ELF]

Adding Lyngdorf to your list... Not sure exactly what the relationship was but they used to work close with TacT.

[sshd]

I no longer care how other people play their music.

 

I was very early with computer audio. Used flac since 2001 and spent years explaining how great it is to have perfectly ripped music available on a server. And how must better a computer is compared to a cd player. Most people laughed, some ignored me, very few listened.

 

DSP/digital room and speaker correction with digital XO is the future. Many people disagree, let them. Many disagree because they have heard something that did not sound right. Well it is not easy and it takes a lot more effort than changing a cable.

 

My current system is wonderful. I love the sound and will never go back to passive XO or uncorrected sound. If other people find the concept interesting, I am wiling to answer questions and help if I can. But I will not attempt to persuade anyone.

 

One thing that annoys me is the hostility from experts. There are several so called experts, who have no clue what they are saying. I am not naming anyone, because I don't care for a fight.

[sshd]

One thing I would like to see is a comparison between the different available products.

 

There are many people satisfied with say Acourate or Audiolense, but I have not seen any comparison between the two or other products.

 

It is not likely there will be a good comparison any day soon. It takes a lot of time to learn a new product and perfect the filter. And then you need a lot of subjective listening.

[Audio_ELF]

Meridian first introduced DSP speakers in 1990... The road is still long...

I no longer care how other people play their music.

 

I was very early with computer audio. Used flac since 2001 and spent years explaining how great it is to have perfectly ripped music available on a server. And how must better a computer is compared to a cd player. Most people laughed, some ignored me, very few listened.

 

DSP/digital room and speaker correction with digital XO is the future. Many people disagree, let them. Many disagree because they have heard something that did not sound right. Well it is not easy and it takes a lot more effort than changing a cable.

 

My current system is wonderful. I love the sound and will never go back to passive XO or uncorrected sound. If other people find the concept interesting, I am wiling to answer questions and help if I can. But I will not attempt to persuade anyone.

 

One thing that annoys me is the hostility from experts. There are several so called experts, who have no clue what they are saying. I am not naming anyone, because I don't care for a fight.

[sandyk]

There are several so called experts, who have no clue what they are saying. I am not naming anyone, because I don't care for a fight.

 

sshd

Yes, audio from a computer can be MUCH better than from most affordable CD players if well implemented .

However, It appears to me that those pushing the hardest for this new sub forum have both feet firmly in the Objectivist camp. Lossless files played "on the fly" MUST sound the same as the original non compressed version.

"Bits are bits" and are such robust little buggers, that you can do whatever you like with them without affecting the sound in the slightest .

 

You can even send them over 5M lengths of USB cable from the local supermarket, or whatever breed of network cable takes your fancy, or over a wireless link.

You can use plastic Toslink, Glass Optical fibre, coax or Firewire.

Hell, you can even use different software players such as Foobar, iTunes, XXHE, jPlay, jRiver, Amarra etc. and they will all sound the same as long as the player is "Bit perfect". (grin)

 

Regards

Alex

[dallasjustice]

If there were a subforum for DSP, I would hope there could be a variety of approaches welcomed. The following Paul Hales interview explains pretty well how I feel about target based DSP.

 

Home Theater Geeks 164 | TWiT.TV

[firedog]

Adding Lyngdorf to your list... Not sure exactly what the relationship was but they used to work close with TacT.

 

Lyngdorf was one of the 2 founders of TACT together with Boz. They split up over differences about how to best build the line (Lyngdorf went multi position measuring, e.g.. TACT didn't). At first the pieces were almost identical, now they aren't. TACT still seems to be alive (licensing technology to Emotiva, there is a new model announced on the Net), but the website doesn't seem to work.

[esldude]

Lyngdorf was one of the 2 founders of TACT together with Boz. They split up over differences about how to best build the line (Lyngdorf went multi position measuring, e.g.. TACT didn't). At first the pieces were almost identical, now they aren't. TACT still seems to be alive (licensing technology to Emotiva, there is a new model announced on the Net), but the website doesn't seem to work.

 

Well even the early Tact had built in provisions for multi-position measurements to be used in the correction along with suggestions on how to best do that. I have spoken to Boz a few times, and he seemed to have no particular preference about either approach. Perhaps that was a point of contention between Boz and Lyngdorf, I rather thought it was more about how to market the product. Whether to leave it highly capable though needing some expertise in use or simplify it. Lyngdorf thinking it was an easier sale if simple. (best would be simple and excellent).

 

I also believe most Lyngdorf equipment mainly corrects only at something like 500 hz and below his feeling that was the area most benefiting. But I may be wrong, haven't used his equipment only read about it.

 

I hope Emotive comes out with a product, but it was due out last August and not available yet.

[esldude]

If there were a subforum for DSP, I would hope there could be a variety of approaches welcomed. The following Paul Hales interview explains pretty well how I feel about target based DSP.

 

Home Theater Geeks 164 | TWiT.TV

 

Is this the same Paul Hales that once made speakers? I still have a pair of his Two Signatures.

 

Speaking of DSP, just to see what was possible, I once used my first Tact to put a Hales Two on the left, and Soundlab electrostat on the right. It wasn't a perfect match, but impressively good. One could listen to it with no real issue at all. As one is a closed box and the other a panel I was mightily impressed. Without the processing they sounded about as messed up as you would expect even when you matched volumes side to side.

[esldude]

sshd

Yes, audio from a computer can be MUCH better than from most affordable CD players if well implemented .

However, It appears to me that those pushing the hardest for this new sub forum have both feet firmly in the Objectivist camp. Lossless files played "on the fly" MUST sound the same as the original non compressed version.

"Bits are bits" and are such robust little buggers, that you can do whatever you like with them without affecting the sound in the slightest .

 

You can even send them over 5M lengths of USB cable from the local supermarket, or whatever breed of network cable takes your fancy, or over a wireless link.

You can use plastic Toslink, Glass Optical fibre, coax or Firewire.

Hell, you can even use different software players such as Foobar, iTunes, XXHE, jPlay, jRiver, Amarra etc. and they will all sound the same as long as the player is "Bit perfect". (grin)

 

Regards

Alex

 

Alex you troll ,

 

I will take the bait. I am mostly of an objective viewpoint. One I describe as rational.

 

I do think mostly DSP would find favor with people of an objective bent. Also if you are going to process a signal you don't get very far very efficiently unless something about the signal can be measured before and after. Otherwise processing is a hit-or-miss affair.

 

I am sure there is someone who has heard DSP and didn't like it. Mostly people of either persuasion find it very obviously beneficial for sound quality.

 

And if a particular forum had mostly objective oriented posters it isn't like this place is over-run with them otherwise. The goal is to get those perfect bits at the output of the players closer to perfect at the brain stem or at least the point where our ears feed them to the cochlear nerve. Is this goal different from what anyone else is trying to do with any form of tweak or particular software or particular gear they are using?

[firedog]

Well even the early Tact had built in provisions for multi-position measurements to be used in the correction along with suggestions on how to best do that. I have spoken to Boz a few times, and he seemed to have no particular preference about either approach. Perhaps that was a point of contention between Boz and Lyngdorf, I rather thought it was more about how to market the product. Whether to leave it highly capable though needing some expertise in use or simplify it. Lyngdorf thinking it was an easier sale if simple. (best would be simple and excellent).

 

I also believe most Lyngdorf equipment mainly corrects only at something like 500 hz and below his feeling that was the area most benefiting. But I may be wrong, haven't used his equipment only read about it.

 

I hope Emotive comes out with a product, but it was due out last August and not available yet.

 

Wasn't trying to say that was the only point of contention between them, just trying to say they had differences over the future of the product, and so decided to split up, but shared the technology they had developed to that point. And yeah, that Emotive amp with built in TACT DRC has been supposed to be ready for the last year.

[sandyk]

Hi Dennis

Several years ago a friend demoed his DEQX. It didn't impress me. IIRC, the DEQX was originally designed for commercial sound reinforcement, and used industrial type converters, which were far from HiFi grade.

To you it's trolling , for the majority of members who regularly report hearing differences between USB cables , Audio software players etc. it's simply stating the bleeding obvious.Have a look at Peter's XXHE forum and you will see some prominent C.A. members who couldn't be bothered getting into no win arguments here with the usual suspects, and see what they say there.Several even own the Phasure NOS DAC as well as using XXHE. Bit Perfect means very little, when various software players can sound quite different, yet output identical binary data.

. Even the vinyl addicts would have a field day crowing how much better it sounds than DSP processed sub optimal digital. ( grin) They already claim that ANALOGUE sounds way better, and far more transparent. Are you going to use DSP to WAY past 20kHz ? It's a waste of time even thinking about new DSD DACs , new DSD DLs and 24/192 unless you do. Many of the Objective crowd already believe anything more than RB CD is a waste of time,because they can hear very little, if any, difference.

Kind Regards

Alex

[Savage]

sshd

"Bits are bits" and are such robust little buggers, that you can do whatever you like with them without affecting the sound in the slightest .

 

You can even send them over 5M lengths of USB cable from the local supermarket

 

That gave me a good laugh

[esldude]

Hi Dennis

Several years ago a friend demoed his DEQX. It didn't impress me. IIRC, the DEQX was originally designed for commercial sound reinforcement, and used industrial type converters, which were far from HiFi grade.

To you it's trolling , for the majority of members who regularly report hearing differences between USB cables , Audio software players etc. it's simply stating the bleeding obvious.Have a look at Peter's XXHE forum and you will see some prominent C.A. members who couldn't be bothered getting into no win arguments here with the usual suspects, and see what they say there.Several even own the Phasure NOS DAC as well as using XXHE. Bit Perfect means very little, when various software players can sound quite different, yet output identical binary data.

. Even the vinyl addicts would have a field day crowing how much better it sounds than DSP processed sub optimal digital. ( grin) They already claim that ANALOGUE sounds way better, and far more transparent. Are you going to use DSP to WAY past 20kHz ? It's a waste of time even thinking about new DSD DACs , new DSD DLs and 24/192 unless you do. Many of the Objective crowd already believe anything more than RB CD is a waste of time,because they can hear very little, if any, difference.

Kind Regards

Alex

 

I don't know any reason you can't do DSP at whatever sample rates you wish. My Tact works at 192 khz.

 

Having seen some vinyl fans who proclaim the already more transparent analog signal act rather funny after complimenting one on the sound of their vinyl only to find the vinyl has been AD'd and handled in the digital realm thereafter color me not very impressed. Vinyl addicts can have their crowing. If they want the benefits of DSP okay, if not they don't have to take part. If they wanted to interact in said DSP forum by saying what others find great isn't well, is that not the same as the oft heard complaint of no one knows what someone else hears?

 

But all of this is a sidetracking issue. If you don't like DSP, then why would it bother someone if others find it helpful and wish to discuss the fine details of it? Why is it that these unmeasurable artifacts that seem hidden from our best efforts are so incredibly important and useful, but easily measurable, easily altered aspects of sound reproduction are thought to be of no real importance?

 

An amp with +/- 10 db specs would be considered broken. In room responses are rarely that good, and yet I am supposed to believe fixing that is somehow bad? I do get a chuckle thinking about it.

[sandyk]

An amp with +/- 10 db specs would be considered broken. In room responses are rarely that good, and yet I am supposed to believe fixing that is somehow bad?

 

If it is at the expense of removing the very worthwhile improvements that many hear between various software players, USB cables, linear PSUs etc. then it is bad.

Just because you can't either hear or measure the differences people hear, using existing digital techniques, doesn't mean that they aren't measurable at

the analogue output of a DAC. If so many people are able to hear the differences, as demonstrated in XXHE forum and numerous threads in C.A. then the differences ARE measurable using suitable test equipment and appropiate analogue measurements.

These differences reside in the low level ambience area where many systems already have degraded S/N ratio. Additional processing will further degrade S/N.

 

Why are their so few replies to the loaded questions in the Poll , when C.A. has around 24,000 registered members ?

Options 1 and 2 are almost identical, and I would assume are designed to inflate the vote in favour of the proposal.

IIRC, Mayhem13 has already made his help in this area available to members, without the need for a special sub-forum.

 

Alex

 

 

 

 

 

 

 

 

 

 

 

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"If you can't hear the difference between an original CD and a copy of your CD, you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist."-Cookie Marenco. cookiemarenco.com/

[sshd]

sandyk: Expressing hostility towards DSP does not automatically include you in the group of so called experts.

 

Like myself, you are probably just someone random writing on the internet not using his real name. You do not have 30+ years of experience recording music. Nor have you invented some audio technology that has changed how music is recorded and played back. In fact music would sound absolutely the same today had you not been born.

 

The anonymity gives you the freedom to express your views freely without making a bad career move. The experts cannot. They make a statement and the world will remember that statement for a long time. Even if they wise up they might not be willing to admit they were wrong earlier.

 

Your readers can choose to care about your views or not. They can argue with you using objective or subjective means. It is a lot easier to argue with a random person than with a well known and well respected expert.

 

 

I do not care about your tiny improvements before the passive crossover. I do not care about digital cables, spdif, or any other 2 channel audio interface. I certainly do not care about which player is being used, which lossless format or even bit perfect output. I am in fact adding digital noise to the 24th least significant bit in addition to completely changing the sound. I know the process is messy and I know I am losing many dBs of dynamic range!

 

But I get rid of 30% distortion in the passive crossover. I gain 4x more power from my amplifiers. I can instantly change my crossover frequencies and the steepness. I can compensate for the problems in my room and speakers impose. I can time align all frequencies, which is messed up by the speaker design. And I can manipulate the sound to match my preferences.

 

Whether or not it the worth the effort depends on the implementation. I am very happy with my implementation. I do not need to read that I must optimise this and that - all I need to do is listen to my system!

 

I am happy with my hobby and it sounds like you are. They are not really compatible, so maybe they should be split apart.

[wgscott]

 

Maybe what is needed is a sub-forum where things like how files with identical md5sums can sound different can be discussed without the interference from those who are simply blinded and rendered too close-minded by logical and physical constraints.

[esldude]

If it is at the expense of removing the very worthwhile improvements that many hear between various software players, USB cables, linear PSUs etc. then it is bad.

Just because you can't either hear or measure the differences people hear, using existing digital techniques, doesn't mean that they aren't measurable at

the analogue output of a DAC. If so many people are able to hear the differences, as demonstrated in XXHE forum and numerous threads in C.A. then the differences ARE measurable using suitable test equipment and appropiate analogue measurements.

These differences reside in the low level ambience area where many systems already have degraded S/N ratio. Additional processing will further degrade S/N.

 

Why are their so few replies to the loaded questions in the Poll , when C.A. has around 24,000 registered members ?

Options 1 and 2 are almost identical, and I would assume are designed to inflate the vote in favour of the proposal.

IIRC, Mayhem13 has already made his help in this area available to members, without the need for a special sub-forum.

 

Alex

 

 

Signature

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"If you can't hear the difference between an original CD and a copy of your CD, you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist."-Cookie Marenco. cookiemarenco.com/

 

So how would you know if DSP would obliterate other differences? It may make them more obvious.

 

If your speaker/room has large response anomalies they are altering the effective SNR in parts of the spectrum which also will cause problems for low level ambiance. If you suffer a hit from processing way down at the last bit or two and gain much more from the processing the net result is a gain.

 

As for the questions in the poll, it was meant to gauge interest. Not make it a yes or no referendum. For one thing I didn't believe others would resent an additional forum even if they didn't care to take part as long as some reasonable number of other people did value an added forum. It didn't occur to me to have a choice saying 'I don't want a new forum' until a couple of people said they saw no need for one.

 

But Alex you are reacting almost as if you feel threatened by a new DSP forum. I don't see why. Do you really think any and all DSP must necessarily be detrimental and wish to stop its use from becoming widespread?

[sandyk]

But Alex you are reacting almost as if you feel threatened by a new DSP forum. I don't see why. Do you really think any and all DSP must necessarily be detrimental and wish to stop its use from becoming widespread?

 

Dennis

 

I believe that digital audio, and that includes Class D amplification, is still in it's early days. At present there are far too many things being reported about digital audio that shouldn't be happening according to present theory. This includes differences due to various types of cables, even including internal SATA cables such as SATA 3 6GB cables that are shielded, or special DIY cables vs. the generic non screened types . This was originally demonstrated by Paul Pang in jPlay forum, and I have also demonstrated differences in CD rips between generic vs. SATA 3 6GBs cables via ULs to a friend in Spain where he used blind techniques to correctly identify the rips using the SATA 3 6GBs cables .There are also numerous reports about differences between bit perfect software players, with several firms supplying relatively expensive players that are highly regarded for their playback quality, and available for both PC and MAC.

We need to sort out these anomalies and get the very best out of the digital we already have before widespread use of further digital processing of a signal. In XXHE forum and elsewhere, there are also heaps of reports about identical .wav files sounding different when played from system memory, that are located on different internal storage devices. We need to find out why, and maximise the SQ that we already have before widespread adoption of DSP for speaker correction. I believe that widespread adoption of DSP at this point in time is premature, although inevitable further down the track.

Regards

Alex

 

 

 

 

Signature

--------------------------------------------------------------------------------

"If you can't hear the difference between an original CD and a copy of your CD, you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist."-Cookie Marenco. cookiemarenco.com/

 

Problem when hocus-pocus works? - Page 5 - General HIFI Discussion - HIFICRITIC FORUM - HIFICRITIC FORUM : hi fi audio systems forum Most recent.See replies 86 to 91

[Hipper]

We need to sort out these anomalies and get the very best out of the digital we already have before widespread use of further digital processing of a signal. In XXHE forum and elsewhere, there are also heaps of reports about identical .wav files sounding different when played from system memory, that are located on different internal storage devices. We need to find out why, and maximise the SQ that we already have before widespread adoption of DSP for speaker correction. I believe that widespread adoption of DSP at this point in time is premature, although inevitable further down the track.

Regards

Alex

 

That's silly.

 

DSP is trying to address other problems. Why should we wait until all the little details of digital are sorted before we address room problems? Developing and using DSP does not stop the enquiries into the problems you talk about.

 

It's like trying develop the concept of a car, but first sorting out every problem regarding engines before we look at drive shafts, tyres etc.. You won't make any progress that way.

[Miska]

At least in my case, "bit-perfect" playback gives the worst sound. So I'm rather running all the oversampling, delta-sigma modulation and digital room correction inside player software. And while doing so, getting better sound than spending 10x more on more expensive dumb hardware...

[sshd]

That's silly....

 

Very silly indeed.

 

A good laserdisk is better than a bad dvd.

A good dvd is better than a bad blu-ray.

A good horse is better than a bad car.

 

Do not stand in the way of progress - you cannot stop it.