Splitting Audio Signal?

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  • 11-14-2004, 04:57 PM
    SilverJS
    Splitting Audio Signal?
    Hi all,

    I have a stereo receiver (Yamaha RX-396) that powers two homemade speakers (8 ohms each). I also have a sub (4 ohm) with its own amplifier.

    My receiver does not have a sub pre-out, so I am now wondering how to hook it up to my system. I believe the best way would be to split the DVD player's output so that it sends two signals - one to the stereo receiver, the other to the sub amp.

    Thus, my questions are :

    1. Is splitting the DVD player's signal actually an option? Will this significantly degrade the sound quality?

    2. If I can do this, is it simply a question of buying two RCA splitters (one for L and one for R), and off we go?

    3. Finally, if the sub amp's input needs to be mono, how could I combine the L-R outputs into a mono one?

    Thank you very much!

    P.S. - if you have any better ideas on how to hook the sub up, please don't hesitate to pipe up....I have also thought about splitting one of the speaker's signals and using a speaker-level to line-level converter, but I believe this would somewhat degrade the sound... My final idea has been to use a simple crossover, but I'd still need to both combine the L-R outputs for the sub one, AND use a speaker-level to line-level converter if I did that!
  • 11-14-2004, 05:09 PM
    markw
    The sub's 4 ohm impedance is a moot point since you're feeding it via it's power amp.

    What type inputs/outputs do you have on the sub?
  • 11-14-2004, 06:38 PM
    SilverJS
    Quote:

    Originally Posted by markw
    The sub's 4 ohm impedance is a moot point since you're feeding it via it's power amp.

    What type inputs/outputs do you have on the sub?

    This is what I'm not sure of. =)

    I'll explain - I previously had a Sony home-theater amp (STR-DE597) powering my speakers, and I was quite nonplussed with the bass. I had thus ordered a sub amp to power my subwoofer, which I already had from a while back.

    Anyway, this weekend, I decided to try out a few amps and found that a home theater amp with a sub certainly didn't give me the sound I was looking for, but a stereo receiver (to my surprise!!) most certainly did. Thus, I bought a stereo amp without a sub out, and I have my sub amp coming in any day. =)

    So, I don't really know what type of inputs it has. You can, however, view it here :

    http://www.solen.ca/sub100.htm

    I ordered it from Solen, but from what I can see, it's this model (on PartsExpress) :

    http://www.partsexpress.com/pe/showd...number=300-792

    I'm not sure if the Hi-Level inputs are actually speaker-level inputs? And if they are, could I use the B speaker on my amp to power the sub??

    JSB
  • 11-14-2004, 07:30 PM
    royphil345
    Don't like splitting the dvd outputs
    I tried it once to try and get sound straight to the tv and to the a/v receiver for times when I didn't want to have the receiver turned on. People do it, but I think it degraded the sound quality. If your sub ends up having only a mono input (which can happen, mine has only a mono input for line level) you're out of luck anyway.

    Using the B-speaker outs on the speaker-level inputs will work very well. Only time it would be a bad choice is when you wanted the sub to support any surround channels as well as the mains. (Some receivers will allow you to route lower frequencies from the surrounds to the main speakers, some will only let you route them to a sub via the sub pre-out.)

    The sub will probably have speaker-level ins and outs which would allow you to hook your A-speaker output straight to the sub and the sub outs to your speakers as another option. The sub's crossover usually cuts some of the lower frequencies from the main speakers which sometimes makes the crossover between the mains and the sub smoother. Can also ease the load on your receiver making the highs clearer. Sometimes though, it will just weaken the mid-bass and you'll want to stick with the B-speaker out method.
  • 11-15-2004, 10:07 AM
    SilverJS
    Thanks Phil,

    Quote:

    Originally Posted by royphil345
    Using the B-speaker outs on the speaker-level inputs will work very well.

    I think so as well. The only thing is that when I expressed interest in the A/B feature of my amp to the salesman, he told me..."Well...you can do it, but it's not a 4 0hm stable amp..." To my knowledge, running two sets of speakers does not mean you're running them in 4 ohm (and besides, I'd just be bringing the B outputs to a sub amp), but do you think this is cause for concern?

    Quote:

    Originally Posted by royphil345
    The sub will probably have speaker-level ins and outs which would allow you to hook your A-speaker output straight to the sub and the sub outs to your speakers as another option.

    I believe mine does indeed. However - I have read the preferred method of connecting a sub is via line level inputs. Will using the speaker-level one degrade sound quality?

    Quote:

    Originally Posted by royphil345
    The sub's crossover usually cuts some of the lower frequencies from the main speakers which sometimes makes the crossover between the mains and the sub smoother. Can also ease the load on your receiver making the highs clearer. Sometimes though, it will just weaken the mid-bass and you'll want to stick with the B-speaker out method.

    One last thing - my amp (or what I THINK my amp is - I got the manual for it from PartsExpress) will indeed let me use the speaker level inputs (A-speaker) and use the outs on it to power the speakers. However, the manual states that if this option is used, the amp crosses over at 125 Hz. The question is, is this fixed? In other words - the amp's crossover is variable 40-160 Hz; if I cross over at 60-80 Hz (as I believe is preferable for a sub), will the rest up til 125 Hz be left out?

    Lots of questions, I realize...hehe...thanks!

    JSB
  • 11-15-2004, 09:55 PM
    royphil345
    Stop worrying...
    The whole point of having A + B speaker switches is to add extra speakers safely. Because the subs output is at 4 ohms doesn't mean the speaker level ins are 4 ohms. I'm sure hooking up the sub at speaker level is an easy load for your amp.

    As far as line level being the preferred method of hookup... I think that's only because of the issues I mentioned with getting sub support for all the channels with only speaker level connections to the mains on a surround system. I believe you said you're doing stereo, so that won't be an issue. Before Dolby Digital, most receivers didn't even have line-level sub outs. Speaker level was the only way to go.

    As far as the crossover thing goes... Yes, that crossover point sounds a little high even for good quality bookshelf speakers. No, there won't be anything you can do about it. So I'd go with the hooking up to the B speakers plan. Just set the crossover point on the sub where you think it sounds best. My brother had a nice little Pro-Logic system a few years ago hooked up exactly this way and it sounded excellent. So stop worrying!!! :)