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I have a pair of BESL S5 MTM speakers, which are large sealed standmounts, designed to be used with subs. I'm using them with a pair of Onyx Rocket UFW-10 subs. I've tried running the BESL's full range (-3dB @ 63 Hz), and rolling the subs in below, but that does not result in a cohesive bass, and the BESL's sound a bit stressed at high volumes when run full range.
I've been trying to find a transparent way to high pass the main amps at 70 Hz, 2nd-order BW. Combined with the natural rolloff of the main speakers, this gives a good LR4 crossover to the subs and allows the system to play quite loud without straining. So far I've tried passive line-level FMod filters, a Marchand XM44 active crossover, and a Marchand XM46 passive line-level crossover. I like the active XM44 the best, and it really is very good, but it loses just a touch of depth and imaging compared to the BESLs running full range. OTOH, the system is smoother and much more powerful at even medium volume compared to the BESL's alone.
So the question is, what's the most transparent way to roll off the main speakers (70Hz 2nd-order BW)? Phil Bamberg recommends the Behringer digital 24/96 crossover, but I don't have any faith it will sound better than the analogue Marchand. I've considered upgrading the power supply on the XM44, and maybe the caps and op amps. The tubed Marchand XM126 seems a bit expensive when all I need is a high pass filter. Any other ideas for a low/no-compromise high pass filter?
Follow Ups:
I would think it would be the "best". Could the real problem be that 2nd order at 70 hertz isn't truly the right thing?
There are things you can do with a digital filter but no way would I consider the Behringer a "step up".
If I was you I'd buy a few extra cards for the XM44 and play. Best to get some measuring gear too. Don't be afraid to try weird stuff, like 4th order 65 hertz on the mains and 1st order 50 hertz on the subs (just a silly example but you get the pic).
Also play with placement of the subs. I'd start with one under each main speaker and then try one between the mains and one halfway back in the room on the side wall firing towards the opposite side wall.
Considering all the problems with getting good bass in a room I'd be inclined to blame something other than the crossover as well as be prepared to try a fair amount of "trail and error".
Russ
> > I would think it would be the "best".I thought the XM46 would do the trick too, that's why I bought it. Unfortunately it sucks the life out of the system. I think the 5.6 Henry (yes henries, not millihenries) is just too big. Even though it's in parallel with the load, it's still in the circuit.
> > Could the real problem be that 2nd order at 70 hertz isn't truly the right thing?
The recommendation on the Bamberg site is 80 Hz second-order, but 70 Hz will work just as well. In fact Phil told me anything from 60 to 100 Hz is fine. I have filters for 80 Hz, but the subs don't sound as good crossed that little bit higher.
> > If I was you I'd buy a few extra cards for the XM44 and play.
I tried a third-order on the subs because they actually roll off at 6dB above 100 Hz unfiltered, but it seems it's better to roll the subs off faster. If they get up too high they make a little bit of a mess.
> > Best to get some measuring gear too.
I do have measuring gear. I use a digital radio shack meter into my laptop with a SpectraPlus analysis program. This setup is very good in the bass range and mid range, not good above 3K.
> > Don't be afraid to try weird stuff, like 4th order 65 hertz on the mains and 1st order 50 hertz on the subs (just a silly example but you get the pic).
A classic 4th-order Linkwitz-Reily should be optimum.
> > Also play with placement of the subs.
The subs are below the main speakers, but you're off track a bit on what the issue is. I still have a bit of fine-tuning to do in the bass, but it sounds phenomenal already. What I'm trying to improve is the audiophilish stuff in the higher frequencies (image palpability and to a lesser extent depth}.
> > Considering all the problems with getting good bass in a room I'd be inclined to blame something other than the crossover as well as be prepared to try a fair amount of "trail and error".
There are definitely problems in my (and most any) room, but the bass is very, very good already. The UFW-10's have a single point EQ that knocks down the main room mode at about 30Hz, which is a major plus.
My system sounds awesome, I'm just being the picky audiophile and trying to get a little more.
I withdraw my negative impression of the Marchand XM46 passive line-level crossover. I must have had something misadjusted or improperly connected, because it sounds totally different now. I'll have to do some listening tests to see whether I prefer it to the active XM44.
"I thought the XM46 would do the trick too, that's why I bought it. Unfortunately it sucks the life out of the system"
The impedance is too low for your preamp to drive and it makes the dynamics suffer (been there, done that).
Anytime one implements either an active or a passive x-over in the line level portion of ones system, there will always be sonic tradeoffs as U have found even with a high quality unit such as the Marchand.The closest I was able to come to a transparent line level x-over was with a combination of an active x-over and a passive x-over with the passive being utilized for the main speaker high pass and the active for the low pass. I even tried the Harrison FMODS and they were not good at all as they overlayed the entire spectrum with grain and the soundstage pretty much collapsed all together. I even tried a car audio active x-over powered by a deep cycle marine battery! While it improved matters, there was still some losses and the setup was not very asthetically pleasing.
The passive x-over was modified M&K HP-80 and the active x-over was an NHT X1. I was where U are at now and was never really satisfied as the losses were too great over the benefits that were provided.
May I make a suggestion? Have U considered one of the REL subbass systems? These only employ the active portion of the x-over in the low pass section of the subbass system with the mains running fullrange and the signal being taken from the amps speaker outputs. Seemless blend and absolutely no signal degradation.
Cheers,
~kenster
Properly integrating a sub with a mid-woofer is really no different than integrating a mid-woofer with a tweeter. You still have to provide complementary slopes so they will combine to acoustically flat. Most people don't get the crossover right, and as a result it never sounds right. I'm using sealed monitors which roll off at 12dB/octave. I'm imposing a 12/octave high pass filter, which gives me 24dB/octave slope and no weird phase changes like you get with a ported speaker. My subs are low passed at 24dB/octave, resulting in a perfect Linkwitz-Riley 4th-order crossover.
The REL method is really no different acoustically than running the sub at line level. I've tried that. The reason I don't like it is that
1. The monitors are not relieved of the lower frequency signals
2. The acoustic slope is wrong... 2nd-order on the monitors and 4th-order on the subs. So the combined phase is a mess and response is lumpy. Bass notes are always a bit slower than the monitors.
I don't consider my speaker system a sub/sat system. I consider it a three-way system, with a very low crossover frequency (below the fundamentals of voice) and implemented at line level. Integration needs all the care that it takes to match a conventional mid to a conventional woofer.
Either my reply was not clearly delienated or the point of my post/reply was missed entirely.
There are some who either don't understand the REL method or they don't know how to properly set up a REL subbass system as I have never had any blending/phasing or lumpy response issues with either of my REL subs although they do take a fair amount of time in adjusting the levels/x-over along with placement with regards to the room boundries to get them dialed in to perfection.
Good luck with your issues.
~
> > Either my reply was not clearly delienated or the point of my post/reply was missed entirely.I understand the REL system very well. There's nothing mystical about it. They run the high level (amp output) signal through a 10K resistor instead of feeding the sub a line level signal. I had the same circuit in a Mirage sub.
Sound waves don't know or care whether the signal traveled through the power amp or not. They behave in exactly the same way in the room. The REL system can work if you have ported speakers with a port resonance above the frequency at which you bring in the subs. (Both the monitors and the subs would have to be -6 dB at the crossover frequency). The problem is, if you have ported speakers with a resonance that high, they're working pretty hard when run full range, and will flap a lot with signals below resonance. If the mains and subs operate in the same frequency range, it will be a bit of a mess, acoustically speaking.
You say you tried to integrate subs using a high pass filter, but did you pay attention to the acoustic slopes of the mains and subs, and the -6dB frequencies? Did you use ported or sealed monitors?
I know I sound a little regimental and I'm sorry about that, I'm not looking for an argument. But if you read Vance Dickason's Loudspeaker Cookbook, you'll see that there's more to integrating drivers than most people understand when they're running a sub/sat system.
I have never had an issue integrating a ported main speaker or an IB or an AS main speaker with a REL subbass system.Granted, the supplied power cord and the high level interface cables (Neutrix) are on the low quality side, but upgrading these 2 cables results in a tremendous increase in the subbass systems resolution which results in a much better ability to mate the subbass system with different driver loading topologies.
My main point to all of this was the deletorious effects that inserting an active x-over into ones electronic chain imposes, not the blending of drivers, which can be tedious yes, but is easily resolved with a bit of judicious tuning.
~
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