[kaxixi]

I am currently running the following setup:

split preamp out -> 2 stereo amplifiers -> one goes to passive subwoofer, the other to NHT superzeros

previously I ran the amps in mono -> sub -> zeros.

The new setup has much better mid to upper end, and allows me to turn the sub off for critical listening with bassless music.  The zeros really sing on their own.  However, the sub really muddies up the sound when its on.

I am guessing that this is because the sub's low pass filter works only when speakers are connected to its output terminals, but I am not sure. I do know the sub does play into the upper frequencies (I can hear voices and such when I turn the zeros off and leave the sub on).

To fix this, I have thought of a few options:

1) build a simple low pass filter with the help of the folks at the DIY forums.
2) sell the second amp and sub, and buy a new sub with tone controls (and room equalization?).
3) buy an R-DES system from av123

I would go with option (3), except the R-DES is no cheaper than option (2), and I am not sure that the R-DES system will act as a crossover at all.

Any advice would be welcome.  Thank you!

[Bingenito]

I vote for option 3

buy an R-DES system from av123

[kaxixi]

Bingenito,  do you mind elaborating?  Do you think I'd be better off with R-DES than a new sub that does much of the same?  And will the R-DES with the relatively high (>100hz) crossover to the zeros?  Thank you.

[Bingenito]

R-DES is less expensive then a new sub with real room correction. The interface seems easy to use and it uses unbalanced ICs.

I do not know of a sub under $1500 that does what the R-DES can but then again I am not a huge fan of subwoofers. Based on what I have seen the Velodyne DD series and Sunfire True Sub EQ are about the only 2 that offer DSP room correction.

I am sure that there are others but if you are happy with the sub itself and just want to correct the lowpass and eq the R-DES seems like the way to go.

[woodsyi]

Before you spend the $299 on R-DES,  see if you can get hold of a 2 channel active x-over for trial and low pass your sub at 80 or 100 Hz to see if that will eliminate the problem.  If yes, you can just DIY a passive low filter; if no, get R-DES and/or treat your room.

[warnerwh]

The Rdes is a wonderful tool but we are presently backordered. Also they're 399 not 299.  Well worth every penny.  Once people use one you won't go back to listening without it.  Makes a major difference up into the midrange.  Bass traps are still necessary.

[woodsyi]

The Rdes is a wonderful tool but we are presently backordered. Also they're 399 not 299.  Well worth every penny.  Once people use one you won't go back to listening without it.  Makes a major difference up into the midrange.  Bass traps are still necessary.

Hello Warner, I guess the sale is over?  I wanted to try R-DES but with my woofers and subs crossed at 50 with my active x-over  I would have needed 2.    I am looking into DIYing a couple of Helmholtz resonators for my peaks instead.

[warnerwh]

Actually I'd not mess with the Hemholz resonators until after I put the Rdes inline. It's much more powerful and versatile.  Also I think you could get by with one and just use RCA splitters.  The beauty is wham bam much better thank you, using the Rdes.

[John Casler]

  I wanted to try R-DES but with my woofers and subs crossed at 50 with my active x-over  I would have needed 2.    I am looking into DIYing a couple of Helmholtz resonators for my peaks instead.

Hi Woodsyi,

Are you running the RM40s full range and then using your x-over as a "low pass" filter to your subs?

It reads like you want to also "low pass" at 50 hz to both your RM40 woofs and the subs???

[John Casler]

I would go with option (3), except the R-DES is no cheaper than option (2), and I am not sure that the R-DES system will act as a crossover at all.

...

The R-DES is "not" a x-over.  It is a lowpass filter and 4 band digital equalizer.  It offers no "highpass" capability.

[woodsyi]

  I wanted to try R-DES but with my woofers and subs crossed at 50 with my active x-over  I would have needed 2.    I am looking into DIYing a couple of Helmholtz resonators for my peaks instead.

Hi Woodsyi,

Are you running the RM40s full range and then using your x-over as a "low pass" filter to your subs?

It reads like you want to also "low pass" at 50 hz to both your RM40 woofs and the subs???

John,  

I am triamping with a 3 way active x-over.  With the coil disconnected, I run ribbons with the passive xover in place one way (I set the active highpass at 200 assuming the updated caps will filter above it), woofers one way between 300 and 50 and the subs lowpassed at 50. I don't know see a way to put just one R-DES to cover bass region from DC to ~120.

[kaxixi]

The R-DES is "not" a x-over.  It is a lowpass filter and 4 band digital equalizer.  It offers no "highpass" capability.

I don't want to high-pass my zeros--I think they sound better precisely because I'm now avoiding the high pass filter in the crossover.  But if R-DES is a low-pass filter, then it would most certainly solve the problem.  Is the frequency adjustable?  Thank you.

[doug s.]

The R-DES is "not" a x-over.  It is a lowpass filter and 4 band digital equalizer.  It offers no "highpass" capability.

I don't want to high-pass my zeros--I think they sound better precisely because I'm now avoiding the high pass filter in the crossover.  But if R-DES is a low-pass filter, then it would most certainly solve the problem.  Is the frequency adjustable?  Thank you.

i would wager that, if you crossed over your zeros with a quality outboard active x-over, (NOT what is in your sub), whatever minute amounts of signal degradation occur (if any), would be *more* than compensated for by them and their amp not having to see any signal below the chosen x-over point.  your speakers will sound *better*, not worse.  this has been my experience, w/many different speakers.

doug s.

[kaxixi]

i would wager that, if you crossed over your zeros with a quality outboard active x-over, (NOT what is in your sub), whatever minute amounts of signal degradation occur (if any), would be *more* than compensated for by them and their amp not having to see any signal below the chosen x-over point.  your speakers will sound *better*, not worse.  this has been my experience, w/many different speakers.

doug s.

have a recommendation?  I don't mind trying this option, either.  Thanks.

[doug s.]

i would wager that, if you crossed over your zeros with a quality outboard active x-over, (NOT what is in your sub), whatever minute amounts of signal degradation occur (if any), would be *more* than compensated for by them and their amp not having to see any signal below the chosen x-over point.  your speakers will sound *better*, not worse.  this has been my experience, w/many different speakers.

doug s.

have a recommendation?  I don't mind trying this option, either.  Thanks.

i'd recommend a marchand, either an xm9 or xm44.  they show up used every now-n-again.  while they may initially seem expensive, since they are at least as good (according to those who have compared; i haven't) to the way-spendy bryston 10b, they are a downright bargain, imo.  db systems also makes a quality x-over, but not nearly as flexible as the marchands.  if yure handy, marchand offers kits, that will really save ya some cash.

or, you could go the budget route & pick up something like an art, behringer or dbx x-over from a pro-audio shop for <$200.  or, even less, if ya find a used one on ebay.  likely not as transparent as the marchands, but still better than what's in your sub, & it would likely still offer an overall improvement to your monitor speakers.  then, ya could always keep an eye open for a used marchand.

http://marchandelec.com/

doug s.

[kaxixi]

i'd recommend a marchand, either an xm9 or xm44.  they show up used every now-n-again.  while they may initially seem expensive, since they are at least as good (according to those who have compared; i haven't) to the way-spendy bryston 10b, they are a downright bargain, imo.  db systems also makes a quality x-over, but not nearly as flexible as the marchands.  if yure handy, marchand offers kits, that will really save ya some cash.

or, you could go the budget route & pick up something like an art, b ...

their xm-1 sounds perfect.  I can request a pair at 125hz, and this would probably solve my problem.  thanks!!

[John Ashman]

Kaxixi, what sub?  What's your room dimensions?  What size subwoofer is it?  Too many variables!

FWIW, SuperZeros should be used with *no bigger* than an 8" subwoofer.  Otherwise, you'll get some issues.  I recommend dual 8" acoustic suspension woofers.  Actually some sealed 10" woofers will do well, like Triad Bronze or something similar, but two good 8" woofers is the best way to get full range out of SuperZeros and you won't have to turn the subs off again.

[John Casler]

I am currently running the following setup:

split preamp out -> 2 stereo amplifiers -> one goes to passive subwoofer, the other to NHT superzeros

previously I ran the amps in mono -> sub -> zeros.

The new setup has much better mid to upper end, and allows me to turn the sub off for critical listening with bassless music.  The zeros really sing on their own.  However, the sub really muddies up the sound when its on.

I am guessing that this is because the sub's low pass filter works only when speakers are connected to its output terminals, but I am not sure. I do know the sub does play into the upper frequencies (I can hear voices and such when I turn the zeros off and leave the sub on).
 ...

1st issue is you have passive sub with apparantly no (or too high)  "lowpass" filter if you are hearing voices through it.

At least some of the muddiness is caused by both your zeros, and the sub producing some of the same frequencies.

This can sound like crap, but can be handled.

If your sub is passive, does it have "outputs"?

I know some of the cheaper subs have "highpass" outs so you can use the same amp for the sub and mains.

What sub are you using?  (Might be better than a guessing game )

[kaxixi]

I am using a passive NHT sub that, I think, never actually made it to market.  Its an acoustic suspension design with two 6" drivers.  John, I've noticed you like acoustic suspension designs from your other posts--I do as well.

The sub has "outputs" which I imagine are high-pass outs.  I disconnected the zeros from these outputs because I thought the sub's low-pass filter would continue to work.  Is it possible that it does not?  I can always go back to running amp->sub->speakers.

[John Ashman]

Ah, you have an SW1 or SW1V.  Those are awesome - not deep (about 40Hz), but also unlikely to boom.  It sounds to me like you have it turned up too loud because you want deeper bass, something it doesn't do.  Have you tried hooking up the SZs through the sub?  You lose a bit of midrange performance, but you get an idea of how the system is supposed to sound.  I recommend trying this and see if you have a problem first.  Then let us know what happened.  

There is a capacitory bypass upgrade for this sub that preserves the midrange.  If you're running the speaker separately, you might be getting a peak ~80-100Hz.  It shouldn't be too bad though.