I don't believe in EQing to try and solve room problems--for what you'd spend on a good EQ you could just as well treat your rooms and get right to the real problem. EQs still won't correct for all the complex problems going on in a bad room. I'm not familiar with the Accuphase, and a several-band parametric wouldn't be enough, and not very natural. I'd recommend experimenting with some room treatments and rent or borrow an RTA to help place them if you're not comfortable doing it by ear.
If the room has acoustic problems, don't change the music--change the room.
Guys...I'm not talking about the normal 1970s type equalizers. Talking about the Rives PARC and a couple of Accuphase models that have been reviewed in TAS and Stereophile and have been claimed to be "invisible" in the system and to correct room problems that years of physical wall, ceiling, etc. treatments have not. Any in-home experience with these products (maybe including the various digital based gear)?
Obviously I'm biased, but I am going to give you my impression, since I've probably heard the PARC in more rooms than anyone else. We've used it full range with everything from very revealing Martin Logans to Genesis 200s to Kharmas to Von Schweikert VR-11s. At many trade shows we have 7 or 8 PARCs installed. Those rooms are a real problem, and the better the equipment, often the worse the problem. Keep in mind, the PARC is for bass only. I agree with the above posts, that you should correct the room as much as possible. Have the PARC do as little as possible. With the PARC, you will still need to deal with high frequency absorption, first order reflections, and diffusion. However, in the bass, correcting with passive treatment is frequently impossible to obtain. To absorb a 70 Hz bump, you are going to need 4 feet of fiberglass (that's depth--not surface area!!). And even if you were to put 4 feet of fiberglass in your room imagine what it would do with the rest of the spectrum. You would feel like you had a head cold just walking into the room it would be so over damped.
Bass has to be equalized, but that doesn't mean you have to use an equalizer. A room with good dimensions is the best way to deal with the bass, but many of us don't have that, and moving walls is out of the question. Absorbers aren't going to work for the above reason. Capacitive type traps, such as RPG Modex or Real Traps can help if the peak is modest and rather broad band (Q factors of 1.5 or less). Then there are custom designed and built Helmhotz resonators. These are large, heavy, and difficult to manage, but they work. Not all of us are willing to build and install one of these--in fact, most people aren't. So what's left? Active equalization.
We developed the PARC because we could not find a device out there that was transparent enough to run full range. Our company's primary business is designing and engineering rooms. If we can start from scratch, the room won't need a PARC. However, if we have an existing room with unfriendly bass response, the PARC is a viable tool. Without getting the bass right, we can not deliver a rewarding experience for our client--and often for existing rooms the PARC is the answer. We keep the signal in the analog domain which has not only great advantages in terms of transparency but also in terms of phase. In the bass the phase shift caused by the room is automatically corrected by the analog circuit in the PARC. This is not a fancy design that builds in time delays or anything of the like--in fact it's the simpliest--analog filters by their very nature have this phase shift, and it's the inverse of the rooms shift. Simple.
Okay, this is the most commercial post I've ever made, but since the question was asked I felt I should at least state why we developed the unit and what we've found. Now someone can dice me up for pitching the PARC.
The Rives is a very different product from the Accuphase which in turn is very different than the Cello. Each is a good product, but they are optimized to accomplish different tasks. You'd get better responses if you stated what type of room deficiencies you're trying to address.
My experience with equalizers (none as sophisticated as those mentioned above) is that they can alter (improve) the sound of recordings, and change a speaker's frequency response, but room resonances stubornly persist, regardless of how you push the controls up and down.
My fix for room resonances is the use of planar speakers. In my room, (quite large and very irregular in shape) with three MG1.6 and three subwoofers, room problems (that I had before) have pretty much gone away. Maybe it's just luck.
I use a z-Systems RDP-1, with three of the 4 paramatric controls providing cuts in the low to mid bass (thus similar in a sense to the Rives), the low shelving control for a slight boost below 35hz, and the high shelving control as essentially a program-specific treble control. I wouldn't be without it or something similar (though of course as it is all digital I am restricted to Red Book sources or analog sources digitized with my z-Systems ADC). No downside that I can hear.
My room is quite small, 11 x 13.5 with 8 ft ceiling. All plaster with heavy carpet and pad over hardwood floor on 1x6 subfloor. I'm getting somewhat boomy bass with some sort of echo slap and I can actually hear the room affecting upper mids and lower highs. I can literally hear the room doing these things as the volume gets louder.
I know the PARC is only an analog bass correction system and the Accuphase is a digital all frequency 'tuner'. I've done two types of room treatments and tried every speaker placement possible. However, kind of restricted as to room treatments because of WAF factor. I'm thinking one of the better equalizers could help with my speaker/room interface.
For 25 years, I've been a purist. Before that, I used Empire and Audio Control stuff. Big rooms, small rooms, Quads, Genesis, ESL's, B&W 801s,02s,05s..., CATS, Carys, Symphonic Lines...
a few months ago, I got a TACT. When I switch it out, EVERYONE, wants to know what "went wrong". VDH Black Beauty, SME V, Big VPI, Emotive Audio Sira...real good stuff, but no room treatment I've ever tried touched this thing. It even makes up for timing errors which EQing can cause adn exaggerate. This is a discontinued model, so I can only imagine how good their new one is.
I'll never be without a TACT or similar product. I wish it were like the RIVES and I didn't have to go into A-D conversions, but purist equipment set ups DO NOT make purist sound reproduction. You've got to get the room out of the way. Tube traps and other room treatments MAY be the ticket, but they're expensive and more or less hit-or-miss.
Thanks, Jeff. I am an SET devotee, have used this type of amp for almost 7 years, and use a passive 'pre-amp'. Can't get much more purist than this and I know exactly what you mean - I can more easily hear the problems the room creates with such a high resolution system. I'll also put the TACT on my short list.
The equalizers people shun are exactly what would help a good many of one. I'm using an Audio Control C101 series three that is mandatory in my well treated room with four bass traps. A db or two here and there can make a big difference in overal sound quality that even room treatment can't make up for without taking up most of he room. My room is 12 x 17 and my speakers are very tweakable VMPS speakers that have far more adjustment than most but the equalizer stays. I can switch it in and out and can hear no difference. My system is ARC LS 16, Sony Dvp 555es, modded kenwood 7500 and VMPS Supertower/R Special Editions. Going with one of the newer digital based equalizers has alot going for it but I have a problem with the d/a and a/d conversion. After thirty years without one I decided to try one for fun, an eye opener it was. Any deleterious effects are easily outweighed by the improvement in sound. I hear no extra noise when switching it in and out with my ear upto the speaker. You can do like I did and I bought a cheap Audio Control Octave off of Ebay to try. After the wow I researched to find a very good analog equalizer for my system. I still have that Octave. I'll send it to you for free if you want to try it just for giggles. You're only out return shipping and it weighs little.I think the S/n on it was 110db. You have nothing to lose!
Warnerwh - What a wonderful offer! If you're serious I'll take you up on it and would be willing to let you try my stored-in-the-closet Creek OBH12 passive remote volume control. However, that Audio Reasearch is a damn good pre-amp but it might be fun to see what a passive would sound like. I'll e-mail you with additional info.
By the way, which digital equalizer did you try out? I'm still very curious about the Accuphase based on The Absolute Sound's review a 2-3 years ago.
Tomryan: Send me your address and I'll send you Audio Control. Be sure to do some research. You'll learn a flat room response is not what necessarily sounds best. As a matter of fact almost nobody likes what truly flat sounds like as the bass is thin and the highs to bright. What you can do though is an eye opener for sure. Regarding digital equalizers I've never used one as I have a problem with the dual conversion. After owning many dacs I was worried the d/a or a/d would be something I don't care for as have been many dacs that are so highly acclaimed. I'm not familiar with the Accuphase but it the frequency response of a room is horrible and most people are shocked when they do in room measurements. Also remember you need to mount a db meter on a tripod or something as moving it just 6" can make a big difference in the readings. If you go to Rives Audio they have some frequency reponse sheets you can print out and make a graph of your room response with. There's no doubt in my mind that only the minority of people have any idea what their room is doing to their sound. Then they go buy high dollar cabling or different electronics and still aren't happy. It's the room and all rooms with walls have modes. Straighten things out some and you'll find the timbres of instruments and voices to be much more accurate and pleasing.
What i want to know is why nobody has mentioned that when you EQ a room, you're actually only correcting for the area where the mic and / or readings were taken. Move the mic / point of readings within the room and you may get very different results. As such, EQ can be helpful, but works best for those that tend to sit in one spot and / or listen by themselves mostly. I say this because someone sitting in a chair or even on the other side of the couch from where the "test results" were calculated will be hearing something different from what you're hearing. That's why it is important to get the room and speakeers dialed in as close as possible and then utilize "tweaks" to finesse it from there ( if necessary ). Sean >
Good point, Sean. Unfortunately, my wife almost never listens with me and I only have friends over for real music sessions a few times a year. But you are right that speakers and room have to be physically corrected as much as possible before going to electronic equalization.
Sean...Procedures for room EQ (that I have seen) always call for the process to be done with the mic in several locations, and the results averaged. Some automatic EQ systems store the results of several runs and do the average for you. (But I'm sure you know this).
When I had conventional cone driver speakers I did play around with room EQ, not with a great deal of success. Since I changed over (back) to three planar speakers and three multidriver (large area) subwoofers I find that the soundfield is very uniform throughout the room, and I no longer need EQ.
That's sort of true. When you have interacting modes it's a reduction in overall energy. While you do correct for one position (or you can actually do an averaging, but I typically don't recommend this method) it's the overall energy reduction for those modes. Now when you are correcting for things other than room modes, then you are aboslutely right and it's very positional dependent.
A test that we did was correcting room modes at the listening position and then sitting somewhere else and putting the PARC in and out of the circuit. It always sounded better in, but it was also a bit better at the spot where the measurements were done. What I found really interesting was when I would sit in a point that was theorhetically the null of one of the most problematic frequencies it still sounded dramatically improved with the PARC in the circuit.
Yes, Rives' comments match my own using a McIntosh C42 preamp. With the tone controls equalizing the seating position (by the way, I don't walk around much when listening to music so this is fine for me anyway), the sound was better anywhere in the room. The modes don't change abruptly and they influence each other - like Rives found out. It is a complex 3D system with all frequencies affecting everything all at the same time. It is not at all straightforward, but having said that, the McIntosh did a fantastic job at equalizing the room.