Rives PARC parametric equalizer

Hi, for those of you who have used the PARC, how many of you feel that the device impacts the dynamics of the sound, and takes some "life" out of it? And if so, was it bothersome?
This is quite normal. I assume you have installed it or you have heard the impact of the PARC in a friends system.

Bass response in 99% of home environments is extremely bumpy due to room modes. Therefore 99% of people with significant bass extension will have some extremly accentuated bass notes, a "Peak". Other bass notes will be muted or nearly non existant as there is a "Null".

Of course, this introduces some additional dynamics in the bass that were NOT on the recording.

Of course, 99% of people who have this problem and do not correct for it quickly get used to this odd bass sound.

=> This odd bass sound becomes "normal" as your brain recalibrates as to how it should sound for your musical favorites.

The first impression of correct bass is that the "WOW" is gone...the BOOM BOOM TIZZ gives way to a more balanced sound.

It takes time to get used to it!

You may notice that you can actually hear a bass riff properly with equal loudness or correct emphasis on each note as the musicians intended.

You may notice suddenly that each individual track sounds completely different to eachother in the way the bass sounds.... rather than the sameness you get when room modes dominate.

So give it time and you will realize that it is like suddenly removing the sugar from your coffee...hard at first....but eventually you realize you can fully taste the coffee and you get more out of it!

Note conceptually it is better to treat your room as much as you can and to get as even an in room bass response as you can prior to EQ treatment with a PARC. One of the criticisms of EQ'ing to adjust for correct bass is that you are adjusting BOTH the primary signal and the reverberant signal TOGETHER to get the right OVERALL level of sound. This means the primary signal is actually muted somewhat due to the preponderence of the reverberant signal. Conceptually some people postulate this may take some of the "edge" off of what you hear in the bass (changing the timbre or the relationship between primary and reverberant field). This is a fair argument...it is well known that a room with large RT60 is disasterous sounding and even if you get the signal levels in the bass correct through EQ you still suffer from overly long reverb times....simply put bass notes last too long and this will mask what you can hear in between these notes.
Shadome--well stated. We have found on installing the PARC in systems where people have been used to the bass bloat for some time, we have to reduce the attenuation on the notch filters as much as 50%. It's almost like we have to ween them off of the bloated bass because they have become so used to it--as you say "recalibrate". We have also found--even for myself, that totally flat is not pleasing. A little interaction with the room and bass is needed to give us a sense of space--a context so to speak. I think some people have gone for flat and found it's a bit on the sterile side, but that is the beauty of it--you can adjust it not only for accurate measurement, but for personal tastes as well.
Thanks to Shadorne and Rives the inventor of the PRAC for your insights. As i stated i like to hear from folks who have used the device. If you are not one of them, please don't bother. I am a PARC user. In my system, i love what it does to attenuate the bass boom from the standing waves in the 35-45 hz range. However, I can subjectively hear that it subtlely curtails the dynamic contrasts and sucks some life out of the overall sound of my LPs. I only attentuate at 40hz. Further up I don't have problematic peaks. instead i have some suck outs in the 100 to 200 hz range.
I am using a power cord and ICs costing the same as the PARC to feed the PARC. I would like to hear from other PARC users whether they hear anything similar to my experience. And was it bothersome?
I have heard the PARC--obviously, in very high end systems. There are a few things that you might do to see what it could possibly do to the signal--we engineered these things in for just this purpose.

First, the bypass is a true bypass. It goes off the audio boards. Second, if you power down then all the circuitry is removed from the PARC and all you are left with is the connections. You might set up a memory that has no attenuation for any band and then go to bypass and then turn the unit off. In theory--if the PARC is totally transparent and has no effect what so ever you would hear no difference in these 3 settings. Let's face it, you are going through a more complex signal path with each of these. In the world of mega buck cables, speakers, and room acoustics you can hear the difference in almost anything--but here is a way to hear exactly what that difference is. Give it a try--you be the judge.
Tks Rives and sorry for late reply...been travelling.. I have obviously tried the bypass mode vs taking the PARC entirely out of the chain. in my system and to my ears, the PARC does something to the sound besides attenuating bass booms. E.g.,the usual slight hiss from my tube pre-amp is greatly surppresed with the PARC in the chain, whether bypass mode is on or off. I don't know if the extra ic causes that.
I prefer PARC out of the chain. However, it would make the bass boom unbearing to listening. So it is a compromise.
I have been using a PARC for well over a year now. Certainly the PARC improves the bass and I prefer less bass bass attenuation then the Bare software recommends. In my system the midrange and treble sounded slightly flattened (2D) and less lucid when processed by the PARC. But I like what it does for the bass.

My speakers support passive biamping and the bass section crosses at over around 300 Hz. So, I ended up biamping with the PARC between the preamp and the bass amp. The preamp signal sent for the midrange and treble amp does not pass through the PARC. I find the midrange and treble sound better this way versus biwiring or using jumpers on the speakers.

Certainly there may be some advantage to biamping and also avoiding processing the midrange and treble through a second set of cables and additional connectors.


Biamping should certainly give you huge improvment in clarity in the mid range, as you will reduce interaction from the crossovers and drivers being in one shared complex hard to drive circuit (read much easier load for each amp and way lower IMD, which is very audible)

=> I am not sure this improvement has necessarily a lot to do with the PARC however...surely it should be transparent in the mid and treble range...whereever it is placed?
Shadorne, in my system and to my ears, the PARC is not transparent in the mid and treble as some reputable magazines have claimed. In addition, in my system, it takes some life out of the sound. However, I must hasten to add that using good quality power cord and i.c. to feed the PARC will reduce the gaps to a subtle level. The PC i use on the PARC costs the same as the PARC (isn't it ridiculous?) but it does help to put most of the life back into the sound again. Before that i used a much humbler PC, and the sound was dissaponting.

Passive biamping of my speakers does offer a slight improvement in dynamics (mostly in the bass) and imaging. I am told that using an active crossover would have a more profound effect. This setup allows me to bypass the PARC for the midrange and treble and preserve the dimensionality and lucidity that I believe the PARC slightly messes with.

In the biwire configuration without the PARC, the dynamics and overall imaging are not quite as good but I did not experience the 2D effect and loss of lucidity in the midrange and treble.

When using a full range signal from the PARC, I agree that the effects of different PCs can be heard. At 300 Hz and below, PC choice is less critical in my system.

If the PARC was the ultimate solution, there would be little market for acoustically designed listening rooms. The cost of such a room could easily exceed the cost of an additional amp, cables and crossover.
Have either of you tried the PARC set flat and compared it with the bypass function?

Of course, if you have dirty power then adding any powered device may add complications. My experience is that digital devices seem most sensitive to power...

I don't doubt the test results suggested by Rives, but it is not a real useful test to me. You are still passing the signal though 2 extra sets of connectors and introducing an extra set of cables. My system does not sound as lucid and dimensional in the midrange and treble as when totally bypassing (removing) the PARC. This applies both to passive biamping and biwire setups. Whether this signal alteration is bothersome will depend on the overall system.

At the time I was testing this, the PARC was being fed by an Exactpower EP 15A and decent PC - Von Gaylord Chinchilla. I do not believe power quality is effecting my opinion.
My PARC is also fed by Exactpower EP 15A. I dont know if it may affect PARC adversely. Anyway in this configuration, and to my ears, attentuation of bass boom not withstanding, the PARC is not transparent compared to if it is out of the chain. A good PC certainly helps to close the gap though.
There is another thread at the moment that speculates how mid range can affect bass perception ....perhaps it also works in reverse too...

....all the same I am puzzled by what you both report but I don't doubt your observations.

Here is the link
I don't think the article is applicable since I can obtain the bass benfefits of the PARC and avoid the midrange problems just by routing the midrange to physically bypass the PARC. I don't believe the physical bypass is equivalent to the PARC's circuit bypass.
Dotsystem is right in that the PARC bypass goes from an input across a relay to an output. If the PARC is totally out of the system you avoid the relay and the additional connection. My point about the test was assume that you must have the connection and yes, that is one more connection and one more opportunity for signal degredation, then what is the PARC doing to the signal once you've made that connection.
Doing what Dotsystem does, i.e., "The preamp signal sent for the midrange and treble amp does not pass through the PARC" would cause a time-delay in the bass section, wouldn't it?

How can a person compensate? Please advise...
Good question Jburidan. I was wondering about it myself.
Rives: is the time delay introduced by the PARC significant enough to be heard or is it something negligible?
I've done what Dotsystem does in a previous system and had no issues. The PARC is an analog device, no A/D and D/A and buffering associated with the time delays. You are right that with a digital parametric this could be a concern, but with analog circuitry it's negligible.
What a great thread. I commend Rives for 'old fashioned' down to earth practical involvement.
I second what Psacanli said. This is a very helpful thread.
Thanks Rives.
You are right that with a digital parametric this could be a concern, but with analog circuitry it's negligible.

Excellent point. This worried me as I use a digital parametric, as far as I can tell from literature it has a 20 microsecond delay (about two samples at 96 Khz). I only pass the sub signal through this EQ (for the same reasons as Dotsystem and the logic that if it aint needed then keep it away in case it does something bad to the mid or treble from the mains). What does 20 microseconds amount to in delay....well it is about two thousands of the wavelength of an 80 Hz signal which amounts to moving my sub woofer back one-third of an inch. So unless I discover that the delay is much worse then I am not worried.

I agree with Rives that Analog circuitry would be negligible - no worry about delay!
Any additional comments from users of the PARC

Super cool system you have there. I always felt a slight loss of resolution. Your system is all tubed and the application I installed the PARC in was all tubed also. It might not be as noticeable in a solid state system. Ultimately, I made room and tuning changes that satisfied me.
Looking at your room, I would recommend some tube traps to experiment with.
Interesting that this topic has returned. The comments by Rhljazz match my viewpoints on this subject. For a tube-based system where harmonic information and 3D is a strength of the system, the PARC is most definitely going to affect the performance of the system in these key areas.

My comments on using the PARC are here
Not only does the PARC alleviate modes that are untreatable with bass traps, ASC Super Traps in my case, reducing those modes significantly opens up the soundstage and transparency and improves elocution significantly.
I use the PARC and it's the best component in my system.

I find it very transparent and agree with Lenny_zwik that it can open up the soundstage. Getting the bass right has a lot of benefits.
thanks for the comments.

With my room - LP cabinets all across the back wall ( behind listening position) and front right side wall make room treatments / bass traps difficult without major changes.

Using the Rives CD, it would seem that my main bass problems are around 40hz (+8db) and 100/125 hz(+12db). Using a cheap behringer Ultra-Q T1951 parametric eq, it would seem that the 100/125 hz causes the most noticable boominess on most music. reducing the 110hz by 7db has helped quite a lot. Still playing around with it.

What acustic treatments are good for the 100/125 hz area's?
ASC Bass or Super traps is what I've used.
Long time this tread was initiated.
But, i must say, using PARC with XTZ Room analyzer PRO II and additional Gik acoustic devices (TRItraps(corners) and 242/244 panels(behind speakers and first+second reflection in ceiling) is nothing less than breathtaking.
The PARC when exactly calibrated (easy and exact with XTZ RA PRO II) does things no absorber(s) are even close doing. Voiding the flutter echo and bass mumble even further enhances all (Gik acoustics devices).
I marvel, this is among the best i have ever heard....