HT cross over question


I am trying to integrate an analog 2 channel stereo plus a sub using a pass through pre amp and two channel amp with my Yamaha HT reciever.
Basically sharing the mains and sub between the two systems.

So... I am not using the LFE output of the AV receiver. I have the LR signal going pre out ... passing through the Audio Research pre amp and then output from the Audio Research as single ended L and R to the line level inputs of the sub... The sub x over is now at 60 Hz... then the sub output is High pass filtered at 80 Hz and going into the single ended inputs of the classe power amp.

I have the Priority of two channel over HT and so the sub's crossover set at 60 Hz and the volume complimenting my Kef 104.2 LR main speakers using the balanced side of my system.. set by ear ... and may be changed over time.

My question is... what should I set the AV cross over?

I have set all of the speakers to SMALL and the AV receiver is set to mix all low frequency info and output to the LR mains (no sub woofer defined for the AV receiver). Currently the AV receiver x over is set to 80 Hz.

My understanding is that multichannel low frequency info including the LFE stuff is digitally filtered at 80 hz in all channels and then all of this info is combined and output full signal to the LR mains and thus sent to my sub. Where the Subs analog filter is sending the 60 hz an lower info to the sub and the 80 hz and above info is output to the LR main speakers.

It would appear that I have created a hole between 60 and 80 HZ...

What should I do to start... raise the sub xover to 80 when I switch between systems?

What should I listen to to optimize these filter settings?

Do I have to break down and get an spl meter?

If I use the balanced side of the system... the AV reciever is sending the full range plus lFE info out through LR which is then ampliied and sent to the mains.. while the sub sees that signal and filters at the cross over (currently set at 60 Hz) Seems like I wind up with too much bass summing here and the Kefs are trying to reproduce all of the boom boom of a theatre track as well.

I am confusing myself! Is there an OK solution?
tcatman
Db I hear good results setting the sub up as you suggest playing music... very pleased with dropping the kube 2000 out..

Avgoround... The problem is the flexibility in connecting the sub . I prioritize two channel music. so the amp takes balanced outputs from the pre and the sub gets the full range pre amp out put to the single ended LR inputs of the sub and cross over as Db suggested.

When I run the Home theatre... I use the same single ended pre amp outs to the sub... set the sub cross over and high pass output to 80 and flip the amp to uses single ended inputs now coming from the sub. its a bit congested but it is a movie..

Everything I read about the sub warns you about using both the high level speaker inputs and the low level single ended inputs. I don't see how I can avoid this setup. The only sub that seems to be able to set up using both inputs are the Rel brand which appears to let you toggle between the two kinds of inputs.
Historically, crossovers built into powered subwoofers have been anything but sonically pure regarding passing midrange/high frequency signals!..degrading overall sound quality to the monitors. Thus, bass is least of my concern in 2 channel music, and keeping the purity of the delicate mid and upper registers is paramount, and i'd default to running speaker level through a switcher top the powered sub, and defeat that for movie playback, if it where me. Again, I would venture that any AB comparison for sonic purity of mid/hi, going both through the sub woofer crossover, and without it, would easily be a discernable advantage,if you NIXED the sub's mid/hi-pass crossover in the mix!!
Nope, seriously doubting that's the best route, IMO
See here in lies one of the problems, in that you're attempting to do a dual purpose system, and you want convenience, and the sonic advantage of a dedicated outboard 2 channel pre plus outboard AV processor working in the same system - which you will have to switch the later in and out of the system anyway. It's a compromise of convenience to isolate the better 2 channel pre-amp for music duties in the setup. This causes a dilema in how one chooses to deal with how the powered subwoofer is to be used in both systems simultaneously, and remain effective for both. And, I find, you either often end up compromising the perfectly flexible and integrated subwoofer transition while swicthing between the two systems, or you maintain the best integration of mid/hi freq sonic purity whilest switching between them, and maybe have a not so convenient subwoofer conversion between the systems! Neither is likely ideal, and has it's pro's and con's in an ideal world.
If HT was my priority, I'd be likely nixing the seaparate 2 channel analog pre amp all together, and simply go with a high end digital AV prepro, and just process my music internally in the DAC's in the pre, with all digital connections, and analog converted or passed direct when you do tuner, turntable, etc. There are a number of them out there, that still sound superb for most people's tastes and applications, such as in a custom integration setup.
If music is your priority (such as yours), I'm probably doing what I suggested, and simply throw a speaker level switcher to switch in and out of the way for the subwoofer in parallel connection for music, and going straight out of the analog 2 ch preamp for music, running the sats full range. (the line level is disconnected when the AV pre/pro is turned off and not in use). Then, when it's movie time- and the AV pre is on and looped in to the 2 ch analog pre - you simply are using the internal digital 80hz crossover to all channels, and the subwoofer is filling in the bottom from the LFE output of your processor -and simply switch the speaker level out of the way from the switcher! Seems pretty straight foreward to me.
Again, this way, I get pure sonics to my sats for full range music, and get to add bass run in paralell. No other crossovers will do anything but degrade my signal purity that im asking out of my expensive analog 2 ch pre, otherwise.
But hey, that's me
HA... talk about my blind spots.... Thanks for pointing this one out...

Once upon a time... I read that using the speaker level inputs to a sub was the worst possible way to feed them. I thought of the speaker level terminals as a relic from the distant past... Consequently... I never thought of the AV solution using the speaker level inputs at all ....much less in this way.

You are absolutely right... by using the HT bass processing and the LFE output of the AV receiver for movies... I should get rid of the congestion I hear right now in the movie soundtracks....

I found this box
Russound AB-2.2
Tabletop A/B selector

which has a max power spec of 150w RMS... The power handling should be fine (Its a 200 W amp)... This box will disconnect the sub speaker level inputs... then the AV receiver does the LFE thing as designed for movies... or any 2.1 listenting I want to do with the AV reciever... stupid simple.... ssshhh.
I will let you know how the theater sounds.
Thanks for the new way of looking at it.
AV
One final question.... I have two crossovers in play now... the AV processor is set at 80 HZ... The sub cross over is set for 80 Hz using the speaker level inputs for music as DB recommended and I concur.. ... (No high pass cross over used)

Is there any problem with this set up of the two cross overs?

Normally... I would turn the sub cross over off... ie 200 Hz. Am I supposed to raise the HT Receiver cross over to something higher when the sub cross over is set for 80hz?

Hopefully the Sub volume level that works for the speaker level inputs and music will also work for the HT receiver and the LFE line level input channel.
Thanks