source for subwoofer signal

[dewardh]

I'm wondering whether it's worthwhile to provided separate (switched) signal paths to my subs for music and HT use. My L and R (stereo) speakers have excellent bass response for music, lacking only in the very low bass. Crossing over to the subs at a typical HT 80 Hz. would do more harm than good for the kind of music (acoustic) that I mostly listen to. But much "electronic" music, and of course HT, really wants the extra bass extension.

One possible way to get both would be to use external crossover (on the L and R channels) at lower than the normal HT crossover frequency, another would be to use an AV receiver with adjustable .1 crossover (but I wonder if that would really work well for HT). Yet another possibility (which I'm seriously considering) is getting a Yamaha AV receiver with a "direct bypass" mode to use for acoustic music listening.

What do you folks do ? ? ?

[ThomasW]

I have fairly large main speakers that certainly can handle bass from acoustic music. But due to the very high sound quality of IB bass I use a sub for everything. That takes the workload off the mains and they run 'cleaner'

I have an Ayre K5xe 2 channel preamp that has a analog bypass mode. All the 2 channel sources are plugged into the K5, as is the main L>R out from my pre-pro.

The settings in the pre-pro are 'off' for the sub, and 'large' for the mains, and 'small' for the effects even though they're certanly not small speakers. Doing this redirects all the bass to the mains

The output from the K5 feeds a Marchand XM9 active XO where the signal is split out to feed the IB and the mains.

[3beanlimit]

I was using the DAC in my pre/pro and with that, used the sub for everything and crossed at 80 hz....

I've since bought a PTec setup (P-1A and the P-3A with SOCS for the front speakers. After having it for a while, unless the CD has really deep bass output....I don't use the sub at all for music.

I do miss using it but hey....I can't give up SOCS...

[dewardh]

Thomas:

That sounds like #2 on the poll . . . you're using the sub as an extension of your "main" speakers. I'm considering doing that also . . . it's a natural progression for someone coming from a "Hi Fi" background (as opposed to a "Home Theater" perspective) . . . but I will probably begin with a "switching" system, using my mains alone for music and a conventional 7.1 for HT while I work out the crossover thing.

What's the crossover frequency from the mains to the sub in your system? What kind of woofer(s) do you have in the mains? (and, kind of OT I know but I'm wrestling with the question now, what do you do for "Center"? I'm thinking that a 3rd "main" in the middle of the screen just doesn't cut it <g>)

dewardh

[ThomasW]

The 'mid-woofers' are a pair of Acoustat 1+1 electrostatic panels.

Until I got the K5 I used a little DIY switchbox that toggled between a Marchand passive preamp out and the pre-pro out.

My active XO is a Marchand that has adjustable frequencies (toggle switch up or down changes frequencies). I use a 60Hz XO point for music and raise it to 80Hz for HT. That helps protect the electrostatic panels from the soundtrack transients

My center is a complete mismatch for the mains. It's a dynamic driver MTM config with dipole 15" woofers flanking either side of the MTM. I have a planar hybrid center on the drawing board, just haven't gotten around to building it.

[jonfo]

I have a pretty complex bass management setup that let’s me do a bit of all of the above.

I feed the sub the .1 LFE output of the pre-pro, but I also crossover the various speakers at different points and add their bass output to the sub. This is mostly so I can run DVD-A/SACD bass management fully under my control. Therefore the pre-pro is configured pretty minimal from a bass management standpoint, all large speakers as far as it’s concerned.

It does require some major summing to take an LFE, the bass from L/R/C/LR/RR speakers, then run it through the BFD and finally into the sub amp. See the diagrams on this page.

A great tool everyone should look into if trying this is the Behringer MX882, which at ~$90 is pretty reasonable. I also use one to gain match the inputs of the Behringer DCX2496 (which does the LR/C/RR).

admin said:

… I have a planar hybrid center on the drawing board, just haven't gotten around to building it.

Thomas, very cool. I’m in design stages for a Hybrid center as well. I’m designing a line array for the mid-bass, the rest will be covered by some ‘modified’ Martin Logan SL3 panels on either side of the LA. This monster will sit behind my perforated screen, bolted to the top of my IB (which makes a nice mount in just the right place). So the center will be a pure line source from 16Hz to 20Khz.

I’m thinking of using the Adire Extremis 6.8 mid-woofer to cover the 80Hz to 400Hz range in my application.

Are you discussing your plans in some thread that I could read? Would love to hear what your design is like.

Cheers,

[qwezxc12]

I use the .1 output on my 7.1 PCI card in my HTPC. I have two Harmon Cardon PA4000 multi-channels bridged into 8 Athena speakers, so I have a full soundstage and good bass response just from the mains/centers/side-rear surrounds. The IB's crossed at 52Hz - lower than most, I suspect, but it sounds extremely smooth and eliminated the "boom" when crossed higher. Runs through an Art Clean Box RCA->XLR Pre-Amp/Converter and a Behringer FeedBack Destroyer.

Just upgraded from a NadyXA900 & Daytron 15" IBs to a BehringerEP1500 and SoundSplinter RL-p 15" D2's Yeah!