Need some advise on setting up Sub

[Jim Bo]

I have been using my Mirage FRX-S8 sub for about a year now but just bought a new Reciver, A sony STRDB1070. I have set up all my speakers to small in the RX menu and have done what I can to make sure I set each of the speakers (all 5)are set to cut the Bass at 80mhz. And I set up the Sub to also cross over at 80mhz. Am I doing this right? Should I leave the speaker as large? should I leave the bass crossover on the Reciver at normal (wich I belive is about 120MHZ?) and just adjust the sub at 80? I want to make sure I get the best bass that I can but I am not sure if I am going about this the right way. If anyone has any know how of setting up a Reciver to match a sub and how to best do it please get back to me.
Thanks:p :rolleyes:

[57U]

The only time the speakers should be set to large, is if they are "large". (frequency response down to say 30-40Hz).

Type "bass management" into your favourite search engine (including the quotes). Lots of information there and lots of different ways to connect things and to set them up.

The only way to properly set up a set of speakers is with test tones (that go from 20Hz to 20kHz and an SPL meter (sound pressure level). As the frequencies change, you should not see more than a couple or 3 dB up or down from the "reference" level. This may not be possible depending on the quality of the speakers, but get the frequency response "curve" as flat as possible. This needs to be done at fairly high levels - 85dB or so. A setup DVD should assist in this since they usually have instructions.

Also RTFM since there are usually instructions in there.

[P175]

Hey there folks, not to disagree at all with what 57u advises, far be it for me argue .. heh :eek: , a word of caution however .. the speaker size [large / small] will further depend on how you connect to your sub. Be very careful here.

If you run your sub directly from the FRONT L/R connections as per some manufacturer specifications, ie: NOT connected to the sub output on the receiver/amp, then you need to set speaker size to LARGE in order for lower frequency signals to reach it.

Most decent speaker systems will provide reasonable connectivity options [diagrams etc] that provide such instruction.

[57U]

Good point. For a while I actually ran my setup this way, but I noticed that the sub's circuitry added some distortion to the signal that ended up going on to the mains. I therefore now have it connected the more "traditional" way with the LFE line level signal going to the sub. Since I have large speakers, I still have the receiver set to "large". Many people do not have large speakers these days....

[Paleface]

should I leave the bass crossover on the Reciver at normal (wich I belive is about 120MHZ?) and just adjust the sub at 80?

If you're using the LFE out to your sub rather than running the sub off of your mains as stated above....

You want to set the LFE crossover on your receiver to probably around 80Hz* and set the active crossover knob on the sub well above that, if not all the way up. That way, the receiver is handling the rolloff and you want to make sure you're not missing anything by setting the subs crossover higher.

* the 80Hz depends on how low your main speakers can go. You want to set the receiver's LFE crossover at a point that can still be reached comfortably by your mains so as not to miss out on any frequencies. So, if you have small sized mains that don't have a lot of bass themselves, you'll want to set the LFE crossover higher (ie: 100Hz) You want some "headroom" there so the sub and mains blend together.. if it's set too low, your sub will sound "disconnected" from the rest of the audio.

[Jim Bo]

Thanks Paleface. I'll give it a try when I get home tonight. Right now I have both the Reciver and the Sub set at 80mhz but I see you're point about setting the sub higher (i'll put it at like 100) so the Reciver only sends the 80mhz and lower frquences to the sub but the sub is not cutting off the bass too soon. I suspect that the knobs on the back of subs for the crossover are kinda' touchy and if it is off a hair I could be missing some freqs.
Thanks again to all.:D