# Why equalize your system?



## neptuneEQ (Dec 22, 2008)

*Why Equalize?*

*Introduction*

You have spent a lot of money for your home theater system and have purchased excellent components. You have had them installed in your home theater room, yet you feel you don't have the sound quality that you expected. Why? In all likelihood the problem is the room itself. Like fingerprints, each room is different. No two rooms are alike and each has it’s own characteristics. 

There are reflections caused by sound bouncing off of walls, ceilings, and floors. There are doors and windows, which act as reflectors, and furniture that will absorb and reflect sound. All of these effects color the sound. A good example of room problems is the feedback effect that we have all experienced in a listening hall when the microphone was being set up. You heard the whistling of the room resonating before the microphone was turned down. The same effect occurs in your listening room. 

What you want to do is to listen to the movies and have them sound to you the way the maker of the movie intended. The following paragraphs give you some of the highlights showing what can be done to improve your listening experience.


*The problem is the room.*

There are many things that effect sound in any room including: The hardness of the walls, the angle of the sound when it strikes the walls, the pitch, the distance from the loudspeaker, the location of the listener, and the interaction of all of these sound waves. In addition to reflections, there are pitch selective absorbers like drapes, carpets and furniture, which also have their effect on what is heard. 

Many of these can be improved to some degree by treating the walls, ceilings, floors etc. In some cases this is difficult or impossible; and in every case, it's not enough. Wall reflections can be improved somewhat by hanging absorbers and dispersers. Floor reflections by carpets; and ceilings by hanging acoustic absorbers. Adding drapes can also help control reflections off of windows.

All of these treatments can be used to improve sound quality, but may not allow decorating the room to your taste. Doing this treatment properly is an expensive process requiring knowledgeable people using expensive test equipment, and still won't really be right, just better.


*How can the room be fixed?*

Fortunately, in addition to the architectural treatments outlined above, there are also electronic systems that can offer very improved audio performance to fix many if not all of these room problems. These electronic systems are called equalizers. Equalizers have been used for professional applications for over 50 years. All high quality movie installations use equalizers to fix problems associated with the theater acoustics. Almost all professional sound installations use equalizers to fix acoustic problems. In the same manner as professional systems, equalizers can be used to make significant improvements in the performance of your home theater by installing suitable equipment. The word suitable is important because there are several types of equalizers manufactured, which operate differently.


*Equalization what is it?*

Equalization is the process of changing the strength of the sound in bands (slices) of audio frequencies so they are equal; thus the name. There are two fundamental types of equalizers Graphic and Parametric. Graphic equalizers break up the sound into a number of fixed bands. Depending on the system this can be as few as two or three or as many as 30 or more. Parametric equalizers have variable frequency bands, normally one, two or three, and try to correct for the worst offenders within the frequency range. Both systems have their place in audio systems depending on the problem being addressed. In general parametric equalizers cost less than graphic. This is because they need less hardware but are also much more limited in the amount of correction they can perform. Graphic equalizers, though more expensive, have much more capability to correct for numerous issues.


*Why you want Neptune Audio's neptuneEQ™*

The neptune*EQ*™ provides the best sound quality available because it is designed specifically for the high-end home theater, using the best components money can buy. It is the only equalizer on the market that does automatic room correction for an entire 7.1 channel home theater installation in a single unit, using state of the art digital signal processing, with *no external computer.*

The neptune*EQ*™ does room equalization using a thirty band graphic equalizer system. It corrects the entire frequency range by splitting it into thirty 1/3-octave bands per channel, plus twenty more for the subwoofer channel for a total of 230 bands! Then correcting for audio imbalances between these bands.


*Powerful yet simple.*

The neptune*EQ*™ system has built in functions to perform _fully automatic_ room equalization. The processor in the unit generates a series of test signals that are then directed to each of the loudspeakers one at a time. A calibrated microphone (provided with each neptune*EQ*™) conveys the reflected sound back to the processor, which then compensates for the room's acoustic effects by adjusting each of the 30 EQ bands, making the room response uniform. And you can do all this with the simple press of a button (well, OK, maybe a little more than simply pressing a button).

In addition to the automatic EQ function there are manual controls available to modify the sound for individual preferences.
To perform the same functions with competing products, you would have to connect specialized test and measurement equipment along with hours from a skilled technician to set up these units. It is costly and still wouldn't give you the quality that can be provided with the neptune*EQ*™.


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## tibuan (Jul 8, 2009)

Cool info! This one should absolutely considerable.


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## hybris (Jan 25, 2009)

What does this thing do that an AV receiver with Audyssey MultEQ doesn't? :dontknow:


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## Moonfly (Aug 1, 2008)

hybris said:


> What does this thing do that an AV receiver with Audyssey MultEQ doesn't? :dontknow:


One might ask the same about the antimode :whistling:


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## hybris (Jan 25, 2009)

Moonfly said:


> One might ask the same about the antimode :whistling:


Hehe, well sure - but I don't own an AV receiver with audyssey (I have a Pioneer), thus I need antimode - which is slightly cheaper than neptune.  

I wasn't trying to be cheeky, I was just curious. I was under the impression that the audyssey-enabled AV receivers had quite advanced EQs nowadays. 512 band EQ + additional EQ for the low end or something like that? I was just wondering what neptune does better and why. 

I guess the obvious difference is that you may actually manually adjust neptune?.., which you can't with audessey (partly why I went with pioneer) or antimode.


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## Moonfly (Aug 1, 2008)

Well I dont know enough about the Neptune device to answer your question. In respect of Audyssey, it uses twice the resolution for the sub channel as is does for the speakers and while you cant alter what Audyssey does, you can still tweak the sub channel in the same way you can on your Pioneer to apply house curves etc :T.

Hopefully someone will help you with the Neptune device shortly.

Cheers


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## Kal Rubinson (Aug 3, 2006)

hybris said:


> What does this thing do that an AV receiver with Audyssey MultEQ doesn't? :dontknow:


I discuss that, to a limited degree, here:
http://www.stereophile.com/hirezplayers/music_in_the_round_37/index1.html


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## hybris (Jan 25, 2009)

Moonfly said:


> Well I dont know enough about the Neptune device to answer your question. In respect of Audyssey, it uses twice the resolution for the sub channel as is does for the speakers and while you cant alter what Audyssey does, you can still tweak the sub channel in the same way you can on your Pioneer to apply house curves etc :T.
> 
> Hopefully someone will help you with the Neptune device shortly.
> 
> Cheers


I browsed a bit around on audyssey.com but couldn't find any information on manually adjusting the EQ (or whatever) for the subwoofer channel to adjust the tonal curve. Do you happen to have any reference to where I could read about that?


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## Kal Rubinson (Aug 3, 2006)

hybris said:


> I browsed a bit around on audyssey.com but couldn't find any information on manually adjusting the EQ (or whatever) for the subwoofer channel to adjust the tonal curve. Do you happen to have any reference to where I could read about that?


Not possible except with the AudysseyPro kit/software.


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## hybris (Jan 25, 2009)

Okay, thank you for your reply


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## Moonfly (Aug 1, 2008)

hybris said:


> I browsed a bit around on audyssey.com but couldn't find any information on manually adjusting the EQ (or whatever) for the subwoofer channel to adjust the tonal curve. Do you happen to have any reference to where I could read about that?


You cant alter what Audyssey does (which I did say), but after it has done its room tuning, and based on what I can do on my Onkyo 875, I can still increase or decrease the sub trim level, tweak the crossover and adjust the bass tone of the subwoofer for increased or decreased bass. There is still a fair bit I can adjust once Audyssey is complete to give the effect of adding house curves etc.

I feel we are falling off topic a little bit though. Perhaps better to open a thread or get involved with Kals debate.

Cheers


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## hybris (Jan 25, 2009)

Moonfly said:


> You cant alter what Audyssey does (which I did say), but after it has done its room tuning, and based on what I can do on my Onkyo 875, I can still increase or decrease the sub trim level, tweak the crossover and adjust the bass tone of the subwoofer for increased or decreased bass. There is still a fair bit I can adjust once Audyssey is complete to give the effect of adding house curves etc.
> 
> I feel we are falling off topic a little bit though. Perhaps better to open a thread or get involved with Kals debate.
> 
> Cheers


Yeah, okay. But you can't actually adjust the EQ for the subwoofer channel. But I can see that the options you have available may enable you to adjust the system to a housecurveish curve depending on your system and response I guess. 

So, to end the audyssey discussion on a positive note for Neptune (which this thread was really about), I conclude that you have far more manual capabilities on the Neptune system than you have on a regular AVReceiver with Audyssey or similar.


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## neptuneEQ (Dec 22, 2008)

Thanks for asking, Hybris.

To answer your question (kind of), we created the neptuneEQ to be a user friendly "anyone can do it" room correction unit with complete manual control. I'm a bit of a control freak, so manual control is important to me. I would never want to put something in my system that said "trust me, I know what I'm doing". From the outset, the goal with the neptuneEQ was to provide a single unit that is powerful enough to take the reins and perform all of the automatic adjustments necessary for a great sounding system that anyone who can program a VCR timer (sorry about the obsolete reference, but it's what sticks in my mind) can use, but flexible enough for a pro (or a more technical user) to manually fiddle with to his hearts content, all the while using the best quality components money can buy.

Getting back to your question, I don't deny that the Audyssey which is built into a receiver is powerful and can do much of what the neptuneEQ can do. Our unit was designed to go with high end separates and perform the tasks it was designed for, thus allowing people who have great gear to keep it and greatly improve their sound. Many people would rather not go out and replace their high end separates with a receiver. Also, the neptuneEQ actually adds the necessary delays, level alterations as well as the equalizations and crossover, rather than simply specifying them (that is compared to Audyssey's stand-alone unit, rather than a built-in receiver unit).

We feel our neptuneEQ can create the best room correction money can buy at this time, but of course we might be slightly biased. Be that as it may, it's certainly the most user friendly, flexible, and least obtrusive room correction device that can be added into a very high end system, so that's what we bring to the table.

Did I mention it ships complete? Mics and all?

Ken


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## hybris (Jan 25, 2009)

Thank you for your answer. 

The manual control bit certainly is very compelling, and I also get the fact that audio purists wouldn't want to put an AV receiver into their signal chain. 
Audiophiles in general pay far too little attention to room acoustics and the option of correcting it both physically and with EQ.


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## Moonfly (Aug 1, 2008)

Now youve gone and grabbed my interest :doh:


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## Kal Rubinson (Aug 3, 2006)

hybris said:


> Thank you for your answer.
> 
> The manual control bit certainly is very compelling, and I also get the fact that audio purists wouldn't want to put an AV receiver into their signal chain.
> Audiophiles in general pay far too little attention to room acoustics and the option of correcting it both physically and with EQ.


Let's take a step back. While it is true that audiophiles, in general, pay too little attention to room acoustics and that most would not want an AVR in their signal chain, use of the NeptuneEQ, fine as it is in all ways, means the insertion of an additional cycle of A/D and D/A in the signal chain. I doubt if "audio purists" would welcome this compared, say, to a high-end preamp/processor with room EQ built into its DSP.

There are many ways to do these things. The hard part is to find the best way for you.


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## neptuneEQ (Dec 22, 2008)

hybris said:


> Thank you for your answer.
> 
> The manual control bit certainly is very compelling, and I also get the fact that audio purists wouldn't want to put an AV receiver into their signal chain.
> Audiophiles in general pay far too little attention to room acoustics and the option of correcting it both physically and with EQ.


I totally agree. One of the things that sticks with me when talking to several audiophiles in an earlier life (as an installer) was how they wouldn't go digital, use any equalization (including bass boost), or use a subwoofer. Times have changed, and most seem willing to at least incorporate subs into their systems as well as go digital. Adding EQ is still a taboo to many I have spoken with, but room treatment isn't.

Personally, I like digital. The specs usually speak for themselves, but to my ears (and knowing what I know about it), the response, distortion and noise levels are all so much better than analog, I would never go back; but I respect other people's opinions. While I remember hearing CDs of LPs I used to own and thought the LPs sounded better (the bass sounded better), I knew the reason was that digital was more accurate, especially after running response curves using test discs and records. It took me time to "train" my ears that the difference I was hearing was lower distortion and flatter response. Now, LPs sound very distorted to my ears (especially toward the end of a side)

So, I opine that it's just a matter of time before more people accept automatic room correction as a necessity. I believe it, as well as acoustic treatment, vastly improve sound quality; and just as digital has all but taken over, word of mouth and people experiencing other people's corrected rooms will spread the word. Just think how much better sound systems are now compared to that of even the 70s. These days, a noise level of -90db is almost considered bad!

Ken


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## neptuneEQ (Dec 22, 2008)

Kal Rubinson said:


> Let's take a step back. While it is true that audiophiles, in general, pay too little attention to room acoustics and that most would not want an AVR in their signal chain, use of the NeptuneEQ, fine as it is in all ways, means the insertion of an additional cycle of A/D and D/A in the signal chain. I doubt if "audio purists" would welcome this compared, say, to a high-end preamp/processor with room EQ built into its DSP.
> 
> There are many ways to do these things. The hard part is to find the best way for you.


I agree and respect your thoughts on this Kal, but I must mention that the extra A/D and D/A are extremely subtle, and differences in different manufacturer's algorithms are much less so.

While keeping a signal digital throughout the process is desirable, unfortunately the ability to do so using certain chosen high end processors and amplifiers isn't practical at this time. Therefore the choice is either buy a receiver or pre-pro which contains the desired room correction product (if it exists), or suffer the (what I believe) negligible effects of the extra A/D-D/A. Surely you would concede that being able to choose a pre-pro by it's other merits is better than having to limit oneself to what's available with a certain room correction unit?

As you say, there are many ways of achieving the ends desired. Everybody has their value systems. We knew the extra conversions would bother some, and some people simply will never be swayed (one conversion with a S/N ratio of -110db and distortion of 0.002% is ok, two is unacceptable), we made sure we have great specs, so those extra conversions are not audible. IMO, the difference in sound between the neptuneEQ and the competition is far greater than the extra conversions (and by that, of course I believe ours sounds better :sn.

Ken


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## hybris (Jan 25, 2009)

Ah, never really considered where in the chain this thing was supposed to be, I assumed it had digital inputs (and possibly outputs), but I understand now that it is supposed to be put into the chain after the preamlifier (which of course makes sense assuming you have several sources). 

I guess the next logical step would be that the preamps (or high end receivers) had digital pre out, and the neptuneEQ and similar products had a digital input as well. That way you could do with only one DA-conversion. 

I guess the benefits of the improved frequency response far outweighs the potential loss in audio quality from the extra conversion, but I see that this would scare away some of the purists.


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## Kal Rubinson (Aug 3, 2006)

neptuneEQ said:


> I agree and respect your thoughts on this Kal, but I must mention that the extra A/D and D/A are extremely subtle, and differences in different manufacturer's algorithms are much less so.


I do agree with you. My point was that posing the "audiophile" or "purist" argument is like wielding a double-pointed spear; it can be used in both directions.


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## Kal Rubinson (Aug 3, 2006)

hybris said:


> I guess the benefits of the improved frequency response far outweighs the potential loss in audio quality from the extra conversion, but I see that this would scare away some of the purists.


Exactly.


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## neptuneEQ (Dec 22, 2008)

hybris said:


> I guess the next logical step would be that the preamps (or high end receivers) had digital pre out, and the neptuneEQ and similar products had a digital input as well. That way you could do with only one DA-conversion.
> 
> I guess the benefits of the improved frequency response far outweighs the potential loss in audio quality from the extra conversion, but I see that this would scare away some of the purists.


YES! That is what I hope will happen. We can work with some manufacturers to get our system inside of their pre-pros, and we have begun talking to a few, but it's not that simple. There are politics involved; for example, a company who is "married" to Audyssey would have a conflict of interest designing our product in, and there are some pre-pro and receiver manufacturers whom we would as soon avoid. Having a digital audio loop (and a digital video loop as well) is something which I believe needs to become mainstream.

Not to mention the fact that we simply can never get built into every manufacturers products, and neither can our competition. So if someone is a fan of a certain manufacturers products (which is common), they don't want to have to look elsewhere for their pre-pro, but still might want an all digital processing path, and whatever room correction they want. the digital loop in a pre-pro then becomes an obvious next step.

Ken


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## neptuneEQ (Dec 22, 2008)

Kal Rubinson said:


> I do agree with you. My point was that posing the "audiophile" or "purist" argument is like wielding a double-pointed spear; it can be used in both directions.


Yes, that's true. That's why we specifically don't market toward them. :unbelievable:


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## Moonfly (Aug 1, 2008)

I'm going to be honest here. Ive used Audyssey since going into the AVR world as it was the first one I used, and Ive stuck with it. As you say, some people stick to their brand, and I can see myself being one of those. I have tried an antimode but I have had results easily as good with the Audyssey built into my amp. I now have a lot of faith in that system and although I looked at the Neptune EQ, I didnt go further because it wasnt Audyssey. Ive even got surprisingly good results on my sealed DIY sub.

I have looked at another Audyssey based device out there but then I think, would I get better improvements spending the purchase price on a kit upgrade and continuing to use the auto eq I already have.

I can see the issues you have getting mass market appeal, as well as dealing with the competition. To that end, I would ask, are you confident that the Neptune EQ does what Audyssey does, and does its as effectively, on top of also including the rather desirable option of manual tweaking?

If your honest answer is a resounding yes, then I have to say the NEQ has to be the top runner in this field.


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## hybris (Jan 25, 2009)

neptuneEQ said:


> YES! That is what I hope will happen. We can work with some manufacturers to get our system inside of their pre-pros, and we have begun talking to a few, but it's not that simple. There are politics involved; for example, a company who is "married" to Audyssey would have a conflict of interest designing our product in, and there are some pre-pro and receiver manufacturers whom we would as soon avoid. Having a digital audio loop (and a digital video loop as well) is something which I believe needs to become mainstream.
> Ken


Go talk to pioneer perhaps, they seem to be the receivers most open to manual control / tweaking at the moment, and they're also one of the simpler when it comes to the EQ-part. The main EQ is only 10 fixed bands + the 3 band parametric EQ for the standing wave control.  

But I'm sure it's a very long way to go before you'd get a deal with one of the main companies. But Audyssey did it, so it can be done


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## hybris (Jan 25, 2009)

Moonfly said:


> If your honest answer is a resounding yes, then I have to say the NEQ has to be the top runner in this field.


How could he say anything else?  

It's obviously a different approach, audyssey having 512 bands (and not fixed?), so theirs is a much more ..detailed approach. Wether that kind of band resolution is required or even effective in the higher bands (where the frequency response change when you move your head an inch to the left or right) I don't know. 

I'm sure the neptune crew have some thoughts to share about their choice of fixed bands (and a limited number of bands). It would be awesome to try a product like the neptune, but it's a little bit outside my price range at the moment, and since I only have an AVR with no power amp I can't even use it. I used to have an Electrocompaniet AW250 + a Denon 3805 before. Maybe I should have kept that and bought the neptuneEQ instead of spending 2000$ on a new Pioneer AVR. :bigsmile:


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## neptuneEQ (Dec 22, 2008)

I am very comfortable with the operation of our neptuneEQ. I have heard it head to head against a few competitors, and that only made me more confident. I was once put on the hot seat and asked which product I preferred in a blind A/B test (ours or a competitor's). I was reluctant to answer because if I picked the other guy's product I would have had to hang my head in shame, but I was asked so I gave my opinion. It wasn't even close, one was very superior, and the other was muddy and harsh. I won't say who's the other unit was of course, but I still have my head up because the one I picked was ours (but of course I knew that deep inside).

Thanks for the tip on Pioneer. This is unfortunately a precarious time for auto room correction. Audyssey was the first to go mainstream, so have a definite foot-in-the-door advantage. Many other pre-pro manu's are "developing their own" or already have, with various amounts of success. This technology is in it's infancy, and the players are being formed. Market positions are being acquired, and opinions abound. All I can say is try us, we offer a money back guarantee :sn:

BTW, where did you find out how many bands Audyssey has, hybris? I looked and looked and never found that info (nor a lot of other info). I did read 512 points which I took to mean 512 FFT resolution points, not filters. I have run tests on Audyssey at our shop, and don't believe they have anywhere near that kind of filter resolution. If they do, I need to go back to school. :rofl2:


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## hybris (Jan 25, 2009)

neptuneEQ said:


> BTW, where did you find out how many bands Audyssey has, hybris? I looked and looked and never found that info (nor a lot of other info). I did read 512 points which I took to mean 512 FFT resolution points, not filters. I have run tests on Audyssey at our shop, and don't believe they have anywhere near that kind of filter resolution. If they do, I need to go back to school. :rofl2:


Hi, I'm no expert in these matters, so I'm not 100% sure what the difference is between points and bands - it certainly isn't obvious from audysseys own explanation. 
http://www.audyssey.com/technology/graphs/graph2.html

From this illustration and description I assumed there were actually hundreds of separate bands, perhaps I'm mistaken.


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## neptuneEQ (Dec 22, 2008)

Yes, thank you Hybris. That is what I remembered seeing last year when I was looking, and it isn't very clear to me either. It tries to be clear, but somehow doesn't quite make it. I know what kind of processing power it takes to do our 30 bands per channel, and what it would take to do 512 bands per. Also, they show points on a curve as if to say we will take this point and place it elsewhere, but of course it's not that simple. If it's a parametric EQ (which to the best of my knowledge they have never said it is), they are adjusting a varying range of frequencies, and if it's graphic, they are adjusting a specific fixed range of frequencies, but either way, it's not a "point" (and if it was, one couldn't hear the effect anyway, since a point is infinitely small).

I heard one person tell me once that they apply a "reverse transfer function" to the response which creates a "perfect mirror image response". That sounds very nice. If they have figured out how to do that, I'd love to learn about it. It seems like a perfect solution, just apply a reverse transfer function.

What I see is that if vague or incomplete information is given out, people have a tendency to fill in the gaps. It is human nature I think, and that tends to work against us, because we are extremely open about what we do. I'm not knocking Audyssey or any other company. I have never seen any indication of dishonesty, and of course a lot of things are proprietary, so how much of their process they would like to disclose is totally up to them. What people read into things is up to those people. I just need to do my best to make sure no mystique is added to what our competition doesn't say. :innocent:

Ken


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## hybris (Jan 25, 2009)

It would have been interesting to see a direct comparison. The before graph, and then the corrected graph from both products. And perhaps adding a few unbiased guys who could blind test the results as well. 

If it works out in your favor I guess it could be interesting information to bring to the table when discussion with the larger AVR companies. 

This page indicates that they do indeed do some kind of mirroring of the frequency response: 
http://www.audyssey.com/technology/graphs/graph4.html


If you click through the numbers on the page there are some information, among other things they indicate that it is NOT a parametric EQ.


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## Moonfly (Aug 1, 2008)

If Neptune would like to send me an EQ, then I'll gladly compare it to Audyssey, I can even compare it to the AS-EQ1 if you wish. I can even do a review and post it on here as well as the UK forum I frequent to give you a foothold in the UK so to speak.

This assumes it works in the UK of course. Let me know the costing involved and I'll have a think about it if it interest you.


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## neptuneEQ (Dec 22, 2008)

Thanks for that link, hybris.

As you say, they do say what they are doing is NOT a parametric EQ. I don't see where they say what it IS, but it's NOT a parametric EQ.

I would be interested in seeing a good unbiased A/B test as well. Moonfly, please email me ([email protected]) about your proposal. I have no problem comparing our EQ to anybody's. Thanks!

Ken


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