[zybar]

In my room, if I have my speakers where they have a deep and wide soundstage, I get some very nasty spikes between 100-63Hz.

I can fix this by moving my speakers much closer to the wall (8' to 3'6"), but it means I lost my deep soundstage.  

For now this is an acceptable compromise, but I ultimately want to have tight bass and a deep soundstage  

From talking to people, it seems like room treatments won't be cheap and will take up too much real estate.

That leaves active crossovers or EQ's.  I am very hesitant to add things to the music chain, but I don't think I have much choice  

So...is anybody using or have experience with the following products:

Marchand active crossovers
Rives PARC
Behringer 1124 Feedback Destroyer

Thanks in advance.

GW

[Psychicanimal]

I use a Marchand X9 Deluxe electronic crossover modded by Dan Wright.  To me it's more a matter of properly choosing and matching components than anything else.  I get seamless integration and invisibility of the subs.  The Marchand's strength is specifically in this particular area. A friend has the Behringer w/ Atma Sphere pre/power and JMlab Micro Utopias.  I'm supposed to listen to them this coming weekend.

My subs are specifically designed for music listening, not HT.  They're evil little subs...

[zybar]

What subs are you using?

Actually, since I don't see a system under your name, what is in your system?

How big is your room?

What mods did Dan do?

GW

[Rob Babcock]

I was just discussing w/Bubba that very subject.  Below is the link: http://www.audiocircle.com/index.php?topic=6200.

[zybar]

Rob,

Thanks for the pointer.  

I have been hesitant to go the EQ route but lots of bass traps are too big and too expensive.

I know that getting the bass right helps lots more than just bass, but did you notice any negatives on the sound?

I guess part of me is skeptical that a $400 list EQ isn't messing things up...
Afterall, all of the signal goes through the EQ eventhough it is just being used for bass.

GW

[Rob Babcock]

No, no part of the signal sees the EQ except the bass.  You want to feed the EQ with a signal from either A) the subwoofer out of a receiver or processor or B) the low passed signal from an external X-over.  The DSP-1124 doesn't contain any X-over.  

I have read a review (I think on http://www.Enjoythemusic.com, but I'm not dead sure) that it was transparent enough to use full range, but I'm as skeptical of that as you are.  I've never tried it, although if I wasn't so lazy I might on a goof.

As long as only the low pass is fed to the EQ, there is no down side.  Bass "speed" ratchets up thru the roof, you can hear subtleties in the bass that you didn't know existed.  Aside from the lack of boom, the speed and depth are the most amazing things.  Once you cut the boom caused by room modes (25 hz & 60 hz were the worst in my room), the truly deep bass become much more apparent.  Where once you had boom the bass bass is taut and DEEEEP as a canyon.

You can buy the Behringer for under $125 from http://www.lentines.com/pa/equbeh.stm;  at the price you really can't go wrong.  (That's where I bought mine- great company to deal with, at least in my case).

One warning- the instructions are crap.  It's easy to program once you figure it out, but be patient for you'll go nuts.  I've been thinking of typing up an "Idiots Guide to the 1124."  Simple once you know how to use it.

[Rob Babcock]

One note:  the rat shack spl meter isn't very accurate at very low freqs.  But it's off by a fairly repeatable, predictable amount.  There are a few places you can get a compensation chart for the Rat Shack analog meter, but I can't remember where off the top of my head.  Maybe someone here recalls.

[Psychicanimal]

What subs are you using?

Actually, since I don't see a system under your name, what is in your system?

How big is your room?

What mods did Dan do?

GW

1) I'm using NHT SW2-Si or something like that (why the weird model #s? ).  They're 10" in diameter and designed with musicality as primary consideration.

2) Modwright Swans M1 mini-monitors, Forté 4 & Marantz Ma-5 monoblocks on one end, KAB modded Technics 1200 & Parasound belt drive transport (in Dan Wright's hands at this time) on the other end.  System runs on a 30 amp, 220V dedicated line, but that's a story on to itself--two 220V/110V  transformers & two Clear Image T4 quad isolation transformer/filter arrays.  Interconnects are Midnight Silver Edition by Ridge Street Audio, for the mo$t part.

3) My living room is 10 x 14 or so but I'm settting up an audio room 10 x 10 1/2 upstairs.  In the works is making four DIY room lenses and Decware corner bass traps.  Near field is the ticket to intimacy.

4) Dan modded the power supply with improved rectification, speed & energy storage plus had the boards cryo treated.  I use a Channel Islands pasive pre and I listen to hardcore salsa--didn't want to lose dynamics and also wanted to keep output impedance to the power amps constant.   It works.

One note:  the rat shack spl meter isn't very accurate at very low freqs.  But it's off by a fairly repeatable, predictable amount.  There are a few places you can get a compensation chart for the Rat Shack analog meter, but I can't remember where off the top of my head.  Maybe someone here recalls.

The Rives Audio test CD compensates for non linearities in the Rat Shack analog SPL meter.

[Rob Babcock]

Thanks, PsychicA.  That's better than a chart.  I may have to pick up that disc myself.

Rives is bookmarked in my favorites, btw.

[mb]

If you were only using the EC DAC. then a digital EQ solution (digital in / EQ / digital out) would give you the EQ needed, while retaining the sonic quality of your dac. In that case, something like the Behringer DEQ2496 would fit you very well. You may want to check my brief review at Audioasylum.

Things are a little more complex because you have both analog and digital sources, and so the analog -> digital -> EQ -> digital -> analog chain has to be good, and that's the domain of the higher end EQs, or a very carefully modded Behringer. Since your Silverlines go pretty deep, unless you have some HP filter on them, the EQ needs to be on both the Silverlines and the REL. Otherwise, with HP filter, the EQ only needs to be applied on the RELs, and the ultimate transparency of the EQ will be less of a factor.

At the moment, my DEQ2496 has -14dB dialled in at 56Hz (1/10 octave notch). That's something that would be very difficult to do with just traps, I think.

[Rob Babcock]

Yes, MB, you can only do that by heading down the Road to the Dark Side- the dreaded "E" word!   I need a similarly rediculous amount off attenuation to fix a couple room modes in my primary room.  So long as this is undertaken by sober, consenting adults, who's harmed?

In all seriousness, a lot of audiophools think EQ is a dirty word, but it really can work wonders, especially with subs.  In real world sized rooms, it's often the only option.  Except to live with peaky, boom bass.

R

[nathanm]

One note:  the rat shack spl meter isn't very accurate at very low freqs.

That is very true it seems, as recently I tried "leveling" the SPLs of the mains and the sub by running pink noise through each indivudually and measuring with the Radio Shack meter.  The sub (XOed at 45-60Hz or so) was easily about 15-20db lower in volume on the meter, but to turn it up to match the level of the mains made it grossly loud, subjectively.  So I thought 'so much for that' and continued to set it by ear.  I'm sure some of that has to do with the fact that the sub is only playing a small part of the spectrum but I also assume the microphone used in the meter is probably not of the highest quality.  I'd be interested to see how it measures with a more serious microphone like Earthworks or something.  It would be nice to know what is really happening, cause parametrically EQing a subwoofer by ear isn't easy either. Hmm.

No matter what it seems like a very expensive and\or labor intensive project to get the bass right. You either have to invest in pricey RTAs and measurement mics, spend hours horsing about with putty, crawl around on the ground a lot, invest in pricey EQs or bass traps, or ultimately - buy a hugely expensive house with rooms having dimensions in excess of 60 feet!    Take that with a grain of salt though, this is from a guy with a square room.  Can you say "glutton for punishment"?

[Andrikos]

Hello guys,
I'm sure you've seen this before but this is the RatShack SPL meter compensation chart:

RadioShack SPL meter   
Compensation Chart   
Frequency   Compensation
(Hz)      (dB)
10      20.5
12.5     16.5
16      11.5
20      7.5
25      5
31.5     3
40      2.5
50      1.5
63      1.5
80      1.5
100     2
125     0.5
160     -0.5
200     -0.5
250     0.5
315     -0.5
400     0
500     -0.5
630     0
800     0
1000    0
1250    0
1600    -0.5
2000    -1.5
2500    -1.5
3150    -1.5
4000    -2
5000    -2
6300    -2
8000    -2
10000   -1
12500   0.5
16000   0
20000   1

[Andrikos]

Oops!
Sorry about the format.
You can (hopefully) see the chart here:
http://www.audiocircle.com/index.php?action=gallery;area=browse;album=146

[Rob Babcock]

Great chart, Andrikos.  If you haven't already done so, you should post a copy of that in the Starting Block.

BTW, I ordered the Rives test CD last nite, the one with test tones recorded with compensation for the Rat Shack meter.  Thanks, PA.

[Psychicanimal]

Great chart, Andrikos.  If you haven't already done so, you should post a copy of that in the Starting Block.

BTW, I ordered the Rives test CD last nite, the one with test tones recorded with compensation for the Rat Shack meter.  Thanks, PA.

You're welcome.  Lak lives some 20 mins away from me and he's got it.  Last night I ordered Granite Audio's Ultimate Low-Bass Test CD.

Here's their sales pitch:

Model #CD-102  Ultimate Low-Bass Test CD

Copyright 2002   Total Running Time 25:48 Minutes

MSRP  $50.00



Test Woofers & Subs

Burn-In Low Frequency Circuits & Gear

Do System Correction For Exact Room Resonance

Hunt Down Vibrating Objects



The Model #CD-102 is specially recorded with every low frequency audio tone from 10Hz to 121Hz in 1Hz increments.  Most other test tone CDs only give a few test tones in this range or one broadband pink noise test tone.  The benefits of the CD-102 having every tone with no gaps is improved accuracy in woofer frequency response tests.  And this full range of test tones is absolutely essential when calculating room resonance frequencies and hunting down vibrating objects in the room that add noise & distortion when excited by their respective resonant frequencies.  Often times the objects & room resonance are excited at frequencies not found on other test CDs, so they go undetected.  Every object in your room has a resonant frequency and it will vibrate and possibly give audible noise when excited by it's resonant frequency when produced by the speaker system.  This becomes unwanted shakes, rattles, and buzzing during music and movie soundtrack playing.  Under normal playback the program material tends to mask the source of these unwanted noises, making them hard to track down.  And, since the object only makes noise when excited by it's resonant frequency, it doesn't buzz all the time.  Many times these noises are mistaken for equipment problems, blown speaker drivers, over-driven speaker drivers, distortion, clipping, etc.  

By having every frequency available through your CD player with a repeat track option, you can play the exciting frequency as long as needed to discover the exact room resonance for correction or hunt down noise problems and find a way to fix it with tape, gum, felt pads, etc.  The CD-102 turns your CD player into a high-resolution low-distortion digital audio generator.  Simply use your direct track entry remote control to select the exact frequency you want to play.  Now, for the small price of this CD you have the full use of an extremely expensive low-frequency audio tone generating system.  Now you can easily test those woofers & subs and track down pesky noises.

Test CD produced by Don Hoglund of Granite Audio using Hewlett-Packard Dual-Channel Digital Storage Spectrum Analyzer, HP decibel meters, Tektronix ultra-low distortion audio signal generator, Tek digital frequency counter, Tek digital decibel meters, and Tascam Pro-Studio CDRW.

Doing all these fine tuning measures is better than crazily spending money...

[nathanm]

Another option would be to download a shareware sound editor app which will more than likely be able to generate sine, square, sawtooth, waves, pink noise etc. , and for "free"!  Make WAV files, burn 'em to CD...

[Psychicanimal]

Another option would be to download a shareware sound editor app which will more than likely be able to generate sine, square, sawtooth, waves, pink noise etc. , and for "free"!  Make WAV files, burn 'em to CD...

What's that?  The only free one I know of is that from Marchand Electronics.

[jacknife]

The Behringer Feedback Destroyer has worked wonders for me in my home theater setup and the price was right at $130.  I had a huge 50hz hump, kind of 1 note bass in my room.  With a lot of work the BFD smoothed the subs out extremely well but it's a pain in the arse to run all the test tones and graph the results and pick filters and try again.

[Rob Babcock]

Did the BFD manual drive you up the wall?  It's almost useless, IMO.  But the unit itself is great, and I got great results.  But as you said, it did take some work.  I had fun once I figured out how to operate it.

That said, the new SOS automatic parametric eq looks pretty cool.  $300, one band, has its own mic.  You plug it in, it plays some tones for a couple minutes, then whamo! it eq's for you.  SGHT gave it a very positive review.  They say you can use a couple of em in seriel if you have more than one major hump.