Good Analog EQ

Looking to integrate some form of analog EQ as a temporary solution until I change my speakers (which is going to take a while).

I can appreciate that adding anything into the signal path is not ideal but I'm wondering if it might be a worthy tradeoff since I have a fairly high resolution system but am not hearing it all because of too much bass (and yes, I have some room treatment already).

If I unplug the low frequency speaker cable from one speaker I get a huge improvement in detail (but of course suffer in other ways), so I'm thinking if I get my hands on some decent equalizer I might be able to improve things.

I use digital room correction for digital sources, but obviously don't want to do this for LPs.

Thanks in advance.
The only analog one I know is the Rives PARC unit, which is fairly transparent. It sure beats putting a digital unit in the chain and suffering an additional a/d and d/a conversion.

Rarely seen on Audiogon though.


ditto Rives. What about speaker placement and listening position. You can make huge differences with such adjustments. Can you describe you positioning?
Marchand makes well-respected stock and custom Active, Passive, Tube and Solid State crossovers and also makes the analog WM8 "BASSIS" Bass Correction Equalizer.

Give them a call, I'm sure they can solve your problem for fairly cheap. Here's their review page
If it's just a temporary solution, then just use the digital room correction. No new interconnects, no new power cords and no new rack space needed. The losses resulting from the added AD-DA conversion could easily be outweighed by the increased resolution across the entire frequency range.
Are you handy at all? With what you describe maybe you could get by with a simple L-pad on the woofers to attenuate the LF until you have a more permanent solution.
Thanks for the responses.

PiedPiper: my speakers are Aerial 9's, my room is 14x25 and soundproofed with ASC wall-damping. This sort of traps bass in to some degree, but the issue is that the Aerials were designed with 'thick bass' in mind; they have 4 7' woofers for low frequencies, 1 6" for midrange. They overload my room. My room is also a home theater so the speakers are on the short wall, about 3' from front and side walls. Seating is at 12' from front wall and I can't change this.

The Aerials have downfiring ports. Instead of using the optional stands (which raise them a few inches, I'm using the stock plastic 1" feet). This seems to congest the bass slightly.

Dan: Your post intrigues me because I keep thinking that if I could could attenuate a choice woofer or two it might help. What is an L-pad? If you wouldn't mind describing what you're thinking of, I'd appreciate it.

I'll check out the leads for Rives and Marchand.

Thanks again,

I have the Aerial model 6 and I hear what your saying about the bass end of the Aerial model 9. The model 6 is a fraction of your Aerial 9's and the bass is just incredible for the size of bass driver. I have had to do some repositioning in a 12 X 15 room just to get them tuned to my liking. The mid/high frequency reproduction on the Aerials is very sweet to my ears but the bass tends to stand out a bit. I did go with the optional stands and it seemed to improve the imaging a bit. Speaker position with the model 6 is tricky and it took time to find the sweet spot.

I put traps in the corners and some acoustic foam but it didn't tame it much. I originally bought a Velodyne DD-10 to go with them and I have never even turned it on. I was looking to upgrade to the 9's but I saw all those woofers and wondered how I would ever get the sound to balance. I am running a single Mac 275 in the winter, a Levinson 23.5 in the summer and I wasn't sure the 9's would be happy with 75 WPC from 6550's.

I wonder if it would help to talk to the guys at Aerial? I hear they are very helpful and ultimately the most knowlegable about the Aerial 9. I'm running purely 2 channel and cant stand the thought of messing with the signal. The fewer things in line from the cartridge to the speaker the better.

I have to tell you that I sat in on a demo of the Model 9 in a room approximately the same size as yours and they were fantastic. It was a completely different set of gear and it took a bit to get them setup. They had the optional stands and the sound was fantastic. I know they model 9's have incredible potential but ultimately wont work in my room. It sounds to me like you have ample space; I believe speaker positioning and the Aerial stands will really help.

Good Luck,
IMHO, the Aeria; 9s were designed for powerful bass, not "thick" bass. As speakers go, they are very flat. Any speaker, especially ones that go as low as the 9s, need to be positioned carefully to avoid the issue your describing.

It is never advisable to position speakers the same distance from both walls as it creates strong standing waves. Moving them out from the back wall and/or closer to the side walls, even a few inches, will help. Moving them out from the back wall will increase your soundstage depth dramatically. The more you do it the better it gets; and it WILL help your bass problem not matter what your Ariels were designed for. One ideal would be 8'4" from the back wall and 2'4" from the side walls. This puts the speakers 1/3 of the way from the back wall and 1/6 of the way from the side walls. This will be a good start at minimizing standing waves. All dimensions calculated from the center of the port, or alternatively, from the voice coil of the woofers, depending on which frequencies are the most problematic.

Your listening position is a few inches from the center of the room, also not good. Again, 8'4" from the rear wall would be one ideal if you followed the above suggestions. If not, you might try moving forward even a few inches. Moving back a few inches will put you right in a hot spot.

If you implemented the above ideals, this would also put you closer to your speakers which would give you a higher ratio of direct to reflected sound, affording you the same volume at the listening position with a lower volume setting on your preamp, which would also help. Towing the speakers in will help with perceived detail.

You could also try plugging the ports with open cell foam, or for more damping, closed cell, but those drivers are not designed for sealed boxes. Mounting the speaker on good brass or steel cones will help as well, and not only the bass. The optional feet you mentioned, of course, would be one option.

These suggestions will be more effective and do less harm, IMHO. If this is not sufficient, Rives specializes in calculating specific recommendations based on your dimensions, etc. Good luck!
FWIW, I just inserted a Velodyne SMS-1 ($600 at Audio into my system. (As a separate matter, I also added a pair of Velodyne SPLR-8 subs). The SMS is a room analyzer/active crossover/parametric eq that analyzes up to 200hz and provides 6 band of PEQ bewteen 20 and 120 cycles.

In my current room, I had bass issues that severely compromised the sound of my Verity Parsifal Encores. (Like you, I almost preferred the system without the Encore woofers on line.) I have had the P/E in 3 other rooms, all of which sounded much better. To start my project, I used the SMS with the Velodyne subs and Parsifal monitors. Bottom line: bass issues are gone. A 12hz bump at 80 hz is gone and several nulls are basically gone, too. I now have +/- 3db response (relative to 80 db) over the 25-200hz range. The mid range magic is back!

I'm still tweaking, but this combo sounds very good so far. It lacks some of the warmth of the straight P/E combo which crosses over symmetrically at 150hz. The SMS features a very flexible low pass, but the high pass is preset at 80hz/6 db per octave, which limits flexibility. If I decide to invest more, I may eventually look to an external high pass (Marchand) to allow me to bi-amp the P/Es at the same frequency & slope that Verity employs for these speakers.

If you can access the woofer in your speaker separately, or are willing to consider subs, the SMS-1 may be a good cost-effective option.

Good Luck,

Thanks again for the responses.

I do have the optional stands and I used to use them, but find they're more boomy with them than without (I attribute that to the bass port being more open).

I have spoken with Michael Kelly and I have auditioned other speakers. The others didn't overload the room the way the Aerials did, but the midrange sounded thin. I guess my room must be causing a null in the midrange as well. Both the Aerial 9's and LR5s seem do have a significant dip between 400 and 1000hz. I have a 15 db difference between these frequencies and 95hz where I have a huge bump (at least according to the graphs that Audyssey room correction shows me).

I have tried stuffing the ports of the 9's with dacron (from my pair of Von Schweikert VR4.5's, which never sounded boomy) but I think that just affects frequencies below where I have the bump and, as Michael Kelly predicted, makes the bass sound more congested at loud volumes.

I will try bringing my speakers further into the room to the positioning you mention, but since I cannot move my listening position, I wonder if I'd be too close - almost near-field monitor range of 4ft or so.
Marty, it sounds like that unit is digital? How do you have it connected?
One other embarassing question, when measuring speaker position from the front/back wall, do you measure from the back of the cabinet or front(woofer)?

I run RCA from the pre to the SMS, then RCA out to my main amps and on to the Parsifal monitors. I also run RCAs from the SMS to my subs. This utilizes the 80hz roll off for the Parsifals.

If I decide to spring for a Marchand X-over, then I'll run a separate pre-out to the Marchand, by passing the SMS in the main signal path. For the bass, I'll still run through the SMS, out to a bass amp, and onward to the Encore woofers.

I believe that the SMS does A to D, for PEQ in the digital domain, but I'm honestly not certain. Since I've so far dealt with frequencies below 80hz, I'm not all that concerned. Whatever damage A/D does, in my room, it is dwarfed by the benefit of the PEQ at these frequencies.

If I want to cross to the Encore woofers at 150hz through the SMS, I'll find out if this favorable cost/benefit can be maintained up to those higher frequencies. As of right now, I haven't tried it, so I don't know the answer.


PS I fully understand the reluctance to add A/D to a minimal path, "purist" analog system. This recent experience has convinced me -at least on a preliminary basis - that, for deep bass, it's worth it.
Measurements should be made from just behind the center of the woofer cone. The Aeriels shouldn't have a dip in the midrange. It's more likely that the room nodes in the bass are eclipsing it. 15db humps in the mid bass due to room/positioning are not uncommon. And as you noted, that hump is way above where the port kicks in. Moving the speakers to 8'4" from the back wall and 2'4" from the side walls will put the speakers about 6' from your 12' listening position, which, although a little extreme, should be a very interesting change for you, as long as you toe them in to point about a foot or so behind your head. Of course experimentation is the key. Avoid 6'3" as this is 1/4 of the room length. 4'2" would be 1/6 but would still be very close to your back wall. 5' mightn't be too bad. How high is your ceiling?

Ceiling is 7.5' high. I think your math is wrong: if my listening position is at 12' and I move the speakers 8'4" out from wall, how does that leave 6' between speaker and me?

I did try this - almost. I probably have the speakers about 7' out and I must admit, the depth of the soundstage is intoxicating. Many instruments still sound like they're coming from the wall, but anything panned 100% to one side jumps forward. I only tried one album so far (Aja), but got the impression that midrange sounds a little thin. But I'm certainly motivated to experiment more than I had been previously - thank you.

Thanks for the response, Marty.
3'8" from you to the axis of the speakers but 6' to each speaker. How did the bass improve? If this is too disconcerting try 5 feet from the back wall. This'll probably work very well for you if the other was too much.
the question is:
do you have too much even bass (meaning too much bass on all bass frequencies), and I would say we talk about sub-bass now (below 100Hz to my ears) - or do you have a few resonating standing bass-waves? if certain frequencies boom, then it´s the room/speaker-placement most likely.
if I remember right 60Hz resonate somewhere around 7-8 meters room(wave)-length.

just some thoughts...
To your original question :) . . . good analog EQs. For a great, flexible hi-fi oriented unit, the McIntosh MQ104 and MQ107 are both very good, and they're pretty cheap and plentiful used from i.e. old Mac dealers, and Audio Classics. They're a bit futzy - you do have to plug/unplug different capacitors to adjust frequency (make sure you get the capacitor kit!), but they are almost as flexible as a pro-style parametric, and sound better than many of the pro units as well.

Parametrics and DSP solutions are also frequently used with some sort of room measurement as well, and it's pretty easy to tie your brain and ears in knots by going down this road . . . sometimes a good-quality, conservatively-used graphic EQ can do wonders, for a lot less headache. For home use, the 2/3-octave style (i.e. Ashly 1502) is a good compromise between precision and fussiness.
11-09-08: Piedpiper: "It is never advisable to position speakers the same distance from both walls as it creates strong standing waves."

They do not create standing waves. It is that equal distances create interference between the direct and reflected radiation at the same frequency for both surfaces.

Kal, perhaps I'm using the wrong words. In any case, the same frequency will be supported by both walls creating a larger bump up at that frequency. The ideal is to distribute the supported room induced frequency anomalies so none get too far out of wack. Thanks for the correction.
Strange that the high end EQs used in the pro audio world aren't considered by audiophiles. For example, there are some very expensive Parametric EQs by Manley (who also makes the Steelhead phono pre) that are well regarded and probably used during mixing of much of the music we're listening to (i.e. they've already been in the signal path).

The pro audio community seems to think these are pretty transparent. They have balanced XLR inputs and outputs, so why aren't these embraced?
Besides mixing, these are probably used for analog mastering.
That's very true, but the pro audio community usually thinks nothing of putting all kinds of things in the signal path for the convenience of manipulability, and are often looking for pleasing colorations rather than maintaining ultimate transparency. IME, you can hear an additional solder joint, let alone a volume pot, active circuit, tube or transistor, coupling capacitors, resistors, etc.. Just because they have already been used in the signal path of the recording, mixing and mastering doesn't mean they wouldn't further degrade the sound. The question is whether what you gain from the device is worth the degradation to YOU. There's no question the Manley EQ is a good one. There's also no question that you could hear its presence in the signal path on a resolving system with its settings set to flat. Some may remember the EQ offered by Cello about 15 years ago, although I believe that was marketed primarily to make EQed recordings iistenable rather than to correct for the room.
Peidpiper makes a good point. There are many types of EQ and each is best suited to particular applications. Manley's Massive Passive is a parametric EQ which could be used for room correction (2channel only) with the support of external measurement/filter calculation programs like REW. OTOH, it is best suited for (and designed for) equalizing the sound source for mastering. Contrast this with modern digital EQs (yes, I know the title of the thread) which can offer a very large number of filters with complex parameters more suitable for the complexity of room acoustics. The first step is to determined what you are trying to accomplish in your particular room.

Also, best to start with an optimized setting so as to minimized required corrections.
Speaking as someone from the pro audio community, I would offer that there are a number of excellent eq's depending on your price range. I would not use a parametric eq of any kind with a stereo system. They are a diffferent animal and meant pretty much for surgical stuff. A transparent broadband eq could be fine or you could go for something with a little more color.

The trouble with pro audio stuff though is that most of it is parametric. EQ causes phase shift so you have to be careful but your ears can be the judge.

A pass filter set might do you well too depending how severe your problem is. These are passive and so they really don't degrade the system much.
correction to my last post: it should read "optimized setup".
Ok, so we're talking Aerial 9's. Close, but not quite up to my 10t's. ;-) Ixnay the L-paday. You don't want to mess up what Kelly has done at all. I can guarantee you that those dips you mentioned are room interactions, not the speakers.

It is all about placement and amp control with these upper end Aerials. The 9's aren't quite as tough as the 10t's to site in a room because of the difference in port location but the same rules of thumb apply. Some of this has been covered by other posters.

They need to be at least 5' from the back wall and at least 3' from a side wall. Personally, I would spend the money on the better Aerial speaker stands before I would put any more components in the chain. But that's just me.

The most important issue with getting the most from Aerials is amplifier control. The amp has to have a vice-like grip on the woofers or you get boomy, muddy bass. I would not use less than 250 watts/ch and probably SS.

Another issue is speaker cables. I would not use any of those fat, high capacitance cables. You can hear that in the bass as well. A nice tight thump becomes more like ttthhhhuuuuummmmppppp.

Your room dimensions are similar to mine, except that I also have a L-shape so there is some more volume in my room. Anyway, I found that the 10ts worked best for me on the short wall, firing down the length of the room. This allowed me to get the speakers about 7' from the back wall, and 3 to 4' in from the side walls. From there you can play with moving your seating position but about about 8 to 10' back from a line drawn between the speakers should be close.
I've heard the 9's in my family room and they sounded MUCH better. Unfortunately, I cannot make them work in my (theater) room. I've tried them 5' from back wall & 3' from sides (had them far out as 8'). I can barely hear singers the midrange is so recessed. And to be clear, I have the stands; they just make things worse (raising them opens the port to allow more bass).

My listening position is around 13-14'; can't change this (riser behind). I use Theta Citadel 1.5 400 watt monoblocks. I also have Bryston 7B 500 watt monoblocks. I don't think power is my problem.

Any other speaker I've tried has not produced the same bass problems (Von Schweikert, Genesis 6.1, Dynaudio C2s, Rockport Miras). Four bass woofers per speaker is just crazy.

Thanks for your thoughts just the same.
Rives might be the heavy artillary you need. They do good work.
Well, I never got the 10t's to sound as good in my listening room as they do upstairs in the theater system either. So I moved on for my 2 channel system. As for the woofers. I don't care what anyone tells you, IMO, 4 seven inch woofers do not do bass as well as one large woofer. ;-)

Good luck!