# Yamaha YDP2006 or Audio Control C131



## tonyvdb (Sep 5, 2007)

I got a used Yamaha YDP2006 for free and Im not sure weather its going to be any better than using my current Audio Control C131 eqs that I currently use on my mains in my Home theater.
I would love some input as to what others think would be better?


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## Jungle Jack (Jul 28, 2009)

Hello,
I am a huge fan of Audio Control. While free is always a wonderful thing, I honestly think your AC EQ will serve you better. I really look forward to reading your impressions.
Cheers,
J


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## tonyvdb (Sep 5, 2007)

Thanks Jack, I was thinking that direction also, I may just use it on my two channel system in the livingroom. Those AC C131s are very clean Its too bad they are so hard to find.


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## Wayne A. Pflughaupt (Apr 13, 2006)

I’ve used them both, and IMO the Yamaha is a better equalizer. The following is excerpted from a review of the YDP2006 I never got around to finishing.


_ The Yamaha YDP2006 is a discontinued model that, as best as I can tell, was in production from about 1996 to 2002. It was an expensive equalizer, with a list price in the neighborhood of $2300. 

>snip<

As we shall see, although I acquired this equalizer simply because it was a better visual match with the rest of my system, the Yamaha has proved to be an absolutely stunning piece of equipment, with features and flexibility unmatched by the Behringer DSP1124, and performance unmatched by the superb AudioControl C-131 1/3-octave EQs I’ve been using in my system for the past twelve years.

>snip<

*Full-range use*
Although I bought the YDP for subwoofer duties, and I typically frown on digital gear in my main-channel analog signal chain, I thought I would insert it across my front L/R channels just for grins, not really expecting much good to come of it. 

To begin, I performed a few crude experiments that I usually run on equalizers to help show if they are decent quality or not. One of those is what I call the “pink noise test.” Pink noise is an unforgiving signal source that can reveal subtle changes in timbre that are easily missed with program material. With all filters set to flat (zero gain), a good equalizer should add nothing audible to the signal. Playing pink noise through the speakers and switching the equalizer in and out, with all filters set to zero gain, there should be no change in the timbre of the pink noise. If there is, then the equalizer coloring the sound, and it shouldn’t be doing that until you apply a change in gain to a filter. The YDP passed this test with flying colors, delivering no audible change in timbre.

Another little test I like to do helps to show if the equalizer has a sufficiently quiet noise floor. This involves turning the receiver’s volume all the way up, with no signal source connected, and switching the EQ in and out, once again with all filters set to flat, to see if it adds any background noise when engaged. (Naturally, great caution is required for this – don’t forget to run the volume control back down before feeding the system an audio signal!) 

A second part of this test looks to see how much noise is added when a boosted filter is engaged. Since any boosted filter adds noise, from a purely technical standpoint the EQ’s background noise should increase in an amount equal to what the filter is adding, and nothing more.

Starting with theYDP2006’s rear-panel switches in the -20 dB consumer-level position, it exhibited virtually no audible hiss with the system volume turned all the way up. I had to put my ear right up against the tweeter to hear any noise at all.

Adding a +12 dB 1/3-octave filter at 6 kHz brought the noise up from dead silent to just barely perceptible – again, with ear to tweeter. Basically, a filter boosted by 12 dB got at most only a few dB in increased noise - certainly nowhere near a 12 dB that should have occurred. This means the Yamaha’s noise floor is considerably lower than the rest of my system. This is remarkable performance. By comparison, my AudioControl EQ introduced noticeably more noise with a 6.3 kHz filter boosted 12 dB. 

Switching the rear panel switches over to the +4 dB pro setting, the YDP did exhibit some noise, slightly more than my AudioControls. It was nonetheless barely perceptible; as with the -20 dB position, you had to have your ear right up to the tweeter to hear it. Certainly nothing that would be remotely audible under normal listening conditions. Engaging the Emphasis noise reduction feature brought the noise level down to par with the AudioControl EQ, but not as good as the -20 dB position.

As with the -20 dB setting, adding a +12 dB filter at 5 kHz in +4 dB mode increased noise only slightly, nowhere near the 12 dB increase that should have occurred – a remarkable phenomenon.


With the YDP’s noise attributes firmly established as “outstanding,” I turned my attention to equalizing my front speakers.

My speakers are a bit soft above about 6 kHz, and with my AudioControl 1/3-octave EQs it required boosting most of the filters above that point 2-5 dB to achieve flat response out to 20 kHz. So the first thing I did with the YDP2006 was correct that. I wasn’t set up to run full-range REW measurements at the time, so I simply used my trusty AudioControl 1/3-octave real time analyzer. Setting the YDP’s #6 filter for high frequency shelving, with a turnover frequency at 5.3 kHz, boosted 5 dB, did the trick. 

My right front speaker is near a corner, while the left one is not. So naturally, the RTA showed different readings between the two speakers in a few places below 400 Hz; The YDP allowed me to match their response more precisely than I had been able to with the 1/3-octave EQs. 

At least one problem in need of adjustment for the left speaker was precisely between two of the 1/3-octave filters on the AudioControls. The 100 and 125 Hz indicators on the RTA had always read a few dB high, and it was a problem I could never adequately address with 1/3-octave equalization. Pulling down the 100 and 125 Hz sliders always resulted in the RTA’s 80 Hz and 160 Hz LEDs (i.e. the ones on either side of 100 and 125 Hz) dropping as well. In other words, fixing one problem only caused another. 

Well, with the YDP2006 I was able to set a filter at 112 Hz – squarely between 100 and 125 Hz - with the precise bandwidth to precisely lower the 100 and 125 Hz LEDs back in line with the rest of response. Behold the power of a parametric equalizer! 

Naturally I wasn’t surprised to find that I could get a RTA reading that looked better with a parametric EQ. But I’ve been fooling around with high-performance equalizers long enough to know that what looks better on a frequency response graph (or a real time analyzer display) doesn’t always translate to improved sound quality. 

The real surprise came when I fired up the CD player for some listening tests (yes, I still have one of those things). Daisy-chaining the AudioControl and Yamaha equalizers made it easy to switch between them for fairly-instantaneous A/B comparisons. I wasn’t expecting any difference worth mentioning, or if anything that the AudioControls would handily dust the Yamaha, just as they had bested every other equalizer I had pitted them against over the years. After all, the Yamaha was saddled with those AD and DA conversions in the signal chain – it didn’t stand a chance. Right?

Well, imagine my surprise to find that the highs sounded cleaner with the Yamaha! Nothing drastic, mind you. I had to switch back and forth between the two equalizers a few times to make sure I was really hearing something. It was rather subtle, but definitely and noticeably there. Sure, the highs sounded better with the AudioControl’s switched in than they did with them bypassed. But changing over to the Yamaha, the highs were definitely more clear and clean. The only way I can describe it, the highs with AudioControl EQs sounded slightly veiled. Clearly, the C131 had finally run up against an equalizer it couldn’t put to shame.

The main thing I can contribute the Yamaha’s improvement in sound quality to is the fact that it was able to accomplish the high frequency adjustment my speakers needed with a single filter, while it took 4-5 filters to accomplish the same thing with the AudioControl equalizers. Further evidence that minimal equalization is always preferable. If you’re the type that believes equalizers are always detrimental to main-channel sound quality, the YDP2006 sounds like there is no EQ in the signal chain at all. 


*Summary*
After using the Yamaha YDP2006 full range and exploring its performance and features, I can see why its price was so high. Quite simply, I would regard the YDP as a high-end equalizer that blows away the best analog models I’ve ever used. Indeed, I’ve had to reconsider my long-standing “no digital equalizers in my analog signal chain” stance. You could pay considerably more than double the $150-250 price these usually sell for on eBay and still get a fabulous deal.

I noted above that I hooked up the YDP2006 to my mains just for an evaluation. The rest of the story: it stayed in my system. That’s right, I never took it out. I resurrected the BFD back to subwoofer duties and promptly retired my AudioControl EQs. I sold them on eBay and bought two more YDPs. 

Needless to say, I can’t say enough good about the Yamaha YDP2006. It’s hands down the finest equalizer I have ever used, easily worth 3-4 times what they sell for._


All that said, I have had issues with a few of these equalizers. I currently have six of them in four separate systems, and have bought at least a couple others that I either resold or had to return. However, the ones with problems have all been units that were “rode hard and put up wet,” as it were – i.e., lived a hard life in touring racks where they were used for live shows or as rental units.

If you can use it with the rear-panel switches in the -20 dB postion, the YDP will be a smidge quieter than the C-131 (if my system is any indicator). The +4 dB position does exact a slight noise penalty, but it’s not enough to matter. Engaging the Emphasis noise-reduction feature with +4 will put the Yamaha back on par with the AC, but personally I’d prefer the insignificant noise penalty to additional processing. 

I have a note in the review that after all filters used were engaged, the YDP ended up being quieter in actual use than the C-131s with the EQ settings I was using for it. Unfortunately, I didn’t note if that was for the -20 or +4 switch positions, but I’m going to hazard a guess it was the latter, as I had already established that the Yamaha was quieter with the former.

Bottom line, give the YDP2006 a shot in your main system, Tony. I’ll be surprised if you’re not impressed. :T

Regards,
Wayne


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## tonyvdb (Sep 5, 2007)

Thanks Wayne, that was very informative to say the least 
I will do that then, how do you think best to hook them up given they only have XLR ins and outs? Do I need to get a Samson s-convert or can I get away with just building some cheater adapters from rca to XLR?


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## Wayne A. Pflughaupt (Apr 13, 2006)

No S-Convert needed, RCA to XLR is fine. A signal converter isn’t needed because it has operating-range switches like the BFD. And besides, those things just add noise. I kept topping out with the consumer -20 dB setting, so I’m running mine at +4. Most of the time the meters aren’t getting much off the bottom, but that’s not a problem. It’s not the big deal some have made it out to be.

Regards,
Wayne


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## tonyvdb (Sep 5, 2007)

Thanks,  I will let you know how it works out.


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## tonyvdb (Sep 5, 2007)

Does anyone know how to do a factory reset on this unit? Im sure there are settings that are not at the factory preset and its messing up the output?


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## Wayne A. Pflughaupt (Apr 13, 2006)

Found this on Yamaha’s website for resetting the YDG2030, which is the YDP’s sister equalizer, a 1/3-octave model. Give it a try:

Press [L] + [R] + [Bypass] while turning on the power.

If it helps, here’s the YDP2006 manual (such as it is).

Regards,
Wayne


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## tonyvdb (Sep 5, 2007)

Thanks, I will give that a try


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## tonyvdb (Sep 5, 2007)

well, Got the YDP2006 hooked up and set. This is a very very sweet EQ  Its got so many nice features and is silent even with all settings at the desired levels. With no signal I cant hear any signal noise change when engaging and disengaging the bypass. I can understand why this unit sold new for over $2000 and even used today still fetches around $400


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## Wayne A. Pflughaupt (Apr 13, 2006)

There’s no reason to pay that much! They typically sell for under $200 on eBay. I even managed to snag one for $50 once - near pristine. :jump:

Regards,
Wayne


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## tonyvdb (Sep 5, 2007)

Thats good, I was not expecting to get it for free so I cant complain. I wonder if i should hang on to my Audio control units or sell them. I was thinking of using them upstairs but that means I need another two channel amp. I have one but it needs repair.


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## tonyvdb (Sep 5, 2007)

Update: see as Wayne has edited his review on the first post I thought I would also add my thoughts now that I have been using the YDP 2006 and a YDG 2030 I have been more than pleased. "Clean" is the right word to use. I have yet to use an EQ that has no noise at all. Even with filters boosted the noise floor simply is in-audible. 
I like these so much I just picked up another 2006 on ebay for $80 including shipping. Absolutely a steal.


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