Originally Posted by DonH50
I think I cross mine at 80 Hz, lost track in all the shifting around recently. It is difficult if not impossible to locate the bass at 80 Hz and below for most folk, and room modes tend to kick in below that, so it makes sense to crossover at 80 Hz and position the subs for the best in-room bass response. And the L/R speakers for best imaging and such. Those two positions are rarely the same. I played with different settings but (surprise, surprise) found around 80 Hz provided the best overall system performance (best in-room frequency response, lowest distortion, best sound/imaging, optimal amplifier power distribution, etc.)
I have never understood the "my subs are only needed for movies" approach. The same issues with room modes and all that jazz applies to music just as it does to movies, and IME/IMO music has a lot more deep bass than people give it credit for. Maybe not in your face like movie explosions, but a sub is a large player for music. I built my first servo sub in the early 1980's solely for music -- HT was not on the radar then (at least not my radar).
Crossover are not brick walls. AVRs typically provide 12 dB/octave meaning if you cross at 80 Hz there is still significant output from the mins (L/R speakers) at 40 Hz -- they will be about half as loud. That means to me (a) I want a speaker with good sound to 40 Hz and (b) I would not want to cross over lower than 80 Hz for the vast majority of speakers. Also remember that even though speakers are rated to play at their -3 dB frequency and below, the vast majority distort heavily with large deep bass signals. Also remember loudness curves -- deep bass can easily be 10- 20 dB or more louder to sound the same volume as higher frequencies, and that takes 10 to 100 times the power, burning a lot of headroom in your amplifier. Better to offload to a sub designed for the task and keep the mains playing cleanly. Everything doing its job, playing together, sounding better.
I have Rythmik and love them. I am familiar with their circuit and their designer and appreciate both. No experience with the other brands but there are many good brands available these days. Still, I'll put in my two cents for Rythmik; their price/performance ratio is tough to beat, customer support is outstanding, and they are highly-regarded for music and movies.
IME/IMO - Don
Thanks, Don. Thorough as usual.
I'm in agreement with just about everything you said.
Just exploring out loud about adjusting the x-over point.
Certainly will try different points and listen for myself. With ARC it makes that a repeatable process.
I did the same thing when setting up my music\theater room 7.2 system. I'll be doing that again in the near future as I'm replacing my L\C\Rs there.
As far as Music v HT subs, there is a difference in what I would do looking at when doing a 2.2 v multi-channel setup.
For one thing I wouldn't be looking at monster subs like Seaton or JTR etc., not that they wouldn't excel but imo, they're total overkill for music.
Film sound tracks can be a lot more intense and sustained on the bottom end. Certainly pipe organ music and electronica can be as well but I can't imagine
that 2 Rythmik 15" subs properly powered wouldn't be able to easily deal with that without breaking sweat.
I'd like to minimize the size of the cabs and that is one reason I'm looking at passive radiator subs.
In my theater room I have 2 SVS Ultra cylinder subs. Not concerned about size or looks there.
When I installed those, 2 subs were considered plenty, now it seems 4 subs are considered a minimum for HT.