[lowtech]

**deleted**

[Rclark]

We've all made our points. Let's get back to servo-non servo discussion. For the record, I'm still not convinced.

[rythmik]

I'm not worried whatsoever.  It's not about hearing or not for me, it's more about putting an emphasis which yields a much larger improvement.  For example, four subs, setup properly, yields me a much greater positive result than any cable that I've tried has.

Tweaking is never as important as the main work and I believe we all in agreement here. You can never publish a paper on how the sound is improved by replacing caps and resistors.  No research funding agent will do that. The entire audio industry is shifting towards DSP. That is where the new funding is. 

[Danny Richie]

For the record, I did get utterly furious when John said servo for OB is a gimmick.

I admit I did not take that too well either. I found that particularly insulting. I have been here with AC from the beginning and have built a good reputation with thousands of happy customers, and one will be hard pressed to find any negative feedback from my customers. I don't sell hype. And to deceive my customers is something that goes against everything that I believe in and base my life around. I don't sell gimmicks, and my customers know this.

But Brian, I am just not going to let that get to me. I will be even more patient in helping John understand what this is and how it works.

[jtwrace]

Tweaking is never as important is the main work and I believe we all agree here.

Thank you.  That's my point!   

[Danny Richie]

I'm not worried whatsoever.  It's not about hearing or not for me, it's more about putting an emphasis which yields a much larger improvement.  For example, four subs, setup properly, yields me a much greater positive result than any cable that I've tried has.

Oh I agree. I am right there with you on that. But I also can't dismiss the improvements that I have heard from cable to cable.

[dBe]

This surely means you are recovered now  .
Take care

Howdy, AJ.  I'm about as recovered as I'm gonna get.  My sternum is in 3 pieces... haven't decided if I want to do surgery to repair it.

It is good to be back to work and trying new things.  You know how us "ear guys" are!    BTW: I knew you would come around to the Mills.  They are marginally cleaner sounding and audio is a game of inches, not miles.

I knew this thread would blow up.  Had to.  No way around it.  I'm gonna keep my nose as clean as possible.  Besides, I enjoy our debates face to face over a beer anyway 

Dave

[jtwrace]

Oh I agree. I am right there with you on that.

OK. 

But I also can't dismiss the improvements that I have heard from cable to cable.

Fair enough.  I've think I've heard changes but again, I'm not so sure that I could blindly pick them out.  I did a test at my place with two cables and one of them sounded broken.  It was very strange and truly the first time I've heard such a thing but there was no reason that I could think of. 

One very expensive and one reasonable (which some may call expensive). 

In the end, I use solid designed cables and move on to much bigger stuff.   

Back to subs!   

[dBe]

I admit I did not take that too well either. I found that particularly insulting. I have been here with AC from the beginning and have built a good reputation with thousands of happy customers, and one will be hard pressed to find any negative feedback from my customers. I don't sell hype. And to deceive my customers is something that goes against everything that I believe in and base my life around. I don't sell gimmicks, and my customers know this.

But Brian, I am just not going to let that get to me. I will be even more patient in helping John understand what this is and how it works.

Danny, Brian: people mock what they don'y understand.  Human nature.  I know that is how I am, but I'm learning that I never was as smart as I used to be.  Now days I follow these guidelines:

Physics rule

Science is where we start on any reasonable project in audio.  Without the science we got nuthin'

Tweaking should be an Olympic sport

Keeping a thread like this from becoming  is next to impossible.  You know me, you'll tell me all about the measurements and the Klippel this and the power response that and what is my standard reply?  Yep, all of that is fine, but how does it sound?  Always amazes me in a realm that involves the appreciation of music and how to obtain the best reproduction thereof that nobody ever asks that question.

Uh-oh.  I just remembered that I used to be an exclusive show me the numbers guy, too.  Nevermind 

Dave

[rythmik]

Well, as it happens... I do have an A.S. degree in electronics technology and a B.S. an another engineering field... and have no trouble communicating with Ph.Ds at work.  As far as the ban goes, it's been in place for years now.  So, who is it that doesn't have a clue?   

Oh, I'm also a member of IEEE.  Do you need to see my card?   

You still missed the point.  I am not a memeber of IEEE and yet I published 6 papers in IEEE journals.  What is the importance of being a IEEE member?  Free pass to fraternity partying?

[lowtech]

You still missed the point.  I am not a memeber of IEEE and yet I published 6 papers in IEEE journals.  What is the importance of being a IEEE member?  Free pass to fraternity partying?

That's not very Ph.D-like comment.  I happen to find their resources very helpful.  Perhaps you should look into it?

Any response about the education credentials of those who you do business with?  Seems like a double-standard...

[Rclark]

The thing that gets me is comments like "every other sub isn't even in the same league" implying, actually straight up saying, that if you don't have a servo sub, you're not going to get the best bass possible. But once you start looking outside this little realm you see that just isn't the case.

[JohnR]

Still not a single shred of technical data to demonstrate the claims made about use of servo for OB.

[Rclark]

 In fact, my hunch is the best bass possible is probably a Magnepan Tympani.

[Danny Richie]

Come on guys. Can we get off the waving of who has the most credentials and personal put downs? Take a breath!

Still not a single shred of technical data to demonstrate the claims made about use of servo for OB.

John, those of us that have it hear to listen to note a considerable difference. I wouldn't be offering it if it didn't. Trust me, I DON'T SELL GIMMICKS. And we are not talking about a subtle difference here. We are talking about a considerable difference.

But all of that aside. Please bare with us and I'll see if I can figure out something with Brian that will allow you to see what is going on.

[JohnR]

Danny, I understand the difference between listening and measuring, but we are not talking about (for example) a piece of wire here, but a circuit that (it is claimed, and amongst other things) changes the effective system Q by a factor of 10. Surely it can't be that hard to show.

I expect we'll have to wait a few years though, as you'll need to get your PhD before Brian will be able to talk to you.

[JohnR]

At normal to even low volume levels it is pretty easy to hear also, but that is at power levels way beyond what I can measure at near field. It will simply max out my mic.

What model is your mic specifically?

[JohnR]

I have a sense you guys are not really EE trained.  Can you any of you two give me a definition of linear time-invariant system, in mathematical equations? Then we can go on with other discussion.

Don't be a dimwit. This is a public discussion forum, there is no "qualification" required for entry or participation. The question is really very simple: can you provide measurements to demonstrate the claims being made for your servo system? Seriously, it's a simple question, that never needed to go where you've taken it.

[Nyal Mellor]

Just wanted to correct some things that have been not fairly stated about the DEQX products.

The new generation HDP-4, HDP-Express II and MATE processors are based on 32 bit / 192 kHz Burr Brown DACs and sound great. They are in the same sonic league as all the similarly priced (i.e. $5k price point) two channel DACs that I (and my customers) have auditioned. The new processors are a sonic level above the $2k price point DACs from Benchmark, Wyred for Sound, etc. I have a few customers who have very pricey DACs (e.g. the TotalDAC, which is $10k+) and they have told me that the DEQX is not as good sonically as these more expensive DACs. As expected really! If you have a super high quality DAD, DCS then get a HDP-4 and use the digital outs. That is the optimal way to set up your system.

The new generation models are very different to the 2.6 and first generation models. The DAC chips, power supplies, analog circuitry is all completely different. The only common thing is the core DSP. So it is not a fair comparison to categorically state the DEQX sounds like 'x' based on evaluation of a 10 year old product.

As for the other comments made about the DSP. The DEQX approach is the most acoustically correct approach to room / speaker correction I know of. Speaker and room correction are NOT the same thing. With the DEQX you measure the drivers nearfield, 'semi-anecoically', using an impulse response window to remove reflections and from that generate a speaker correction filter which fixes the frequency response, phase and group delay issues of the drivers themselves and their mounting in the speaker baffle. If you have taken a good measurement (preferably outside as DEQX recommends) then all you are correcting is the speaker NOT the room. Once you have done the speaker correction you move the mic back to the listening position and take a measurement. That measurement gives you the combined response of the speaker and room. From that you generate correction filters ONLY in the low bass, below say 100Hz ideally. In this region parametric EQ is extremely effective as an alternative to passive acoustic treatment. Just because you are using a DEQX does not mean you should ignore room treatment. Rather the DEQX is correcting the speaker response, and giving you a tool (parametric EQ) to deal with the worst low bass issues that the room introduces.

Finally, the DEQX is not ideal for use with dipole bass using low Qts drivers that need a lot of correction. There are no manually configurable shelving filters available so you are kind of fudging the software to try and correct the rolloff for you. I have used dipoles in the past and found that to around 10dB of correction you could make it work by using parametric EQ filters with a very low center frequency as a quasi shelving filter.

[Davey]

John,

It's not like they're in an industry that provides real/valid explanations for audible claims.  The whole industry is full of it (little pun there.)

I'm actually fine with Danny's exclamation that you just need to hear/experience the result and not worry about the technical details.  If potential customers are convinced and lay down their money, excellent.

I think it might be easier and more successful if Brian would actually take down a bunch of the technical information on his website.  Most of the customers wouldn't really care one way or the other, and it would preclude him getting bogged down in discussions like these.

Anyone, besides me, in this thread ACTUALLY have dipole basses in use with their Maggies? 

Cheers,

Dave.