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I've got an Xtant 1.1i 100 watt mono amp on the way that I plan on using to power a pair of 6w0's for rear fill and a bit of midbass reinforcement(my 5 1/4" Q's don't cut it).

The problem is that this amp has a single mono input so I need to find some way to convert the bandpassed stereo signal from my crossover to mono. I've heard of some people simply using a y-connector, but I always thought this wasn't a very good idea so have never tried it. Shouldn't I utilize some sort of summing amp instead?

Anyone have any comments or suggestions?

thanks in advance

-Fishy

You should just use a y adaptor. I thought about it and I understand what you mean by it, but you are making it overly complicated. I've done the sort of thing before with recording equipment/keyboards/etc...

You will be fine in other words.

Lol, a little bit of "knowledge" combined with a lack of practical experience sure DOES complicate things at times.

Guess thats why a lot of Techs hate those damn Engineers so much.



thanks for the help

:happy055:

-Fishy

Guess thats why a lot of Techs hate those damn Engineers so much.

Yea i can vouch for that being a car mechanic. The engineers have no respect for us 'grease monkeys'. LOL

TEDD

actually that's the difference between an engineer with a piece of paper, and one with experience. a good engineer considers things like the ability to service whatever is being designed etc.

anyway, a simple Y cable can cause feedback when you're trying to use it as a combiner. that's why diodes are generally used to prevent that in a summing circuit.
It'd be simpler to just use the left channel feed as your mono input, which is what's done universally for a mono signal from a stereo source.
that way you're not going to get any feedback. besides, below about 250Hz, everything is mono anyway. stereo separation is for spatial perception by the human ear, and humans don't really perceive spatial separation below the vocal range which is usually over 250-500Hz (right in that 1 octave range)

Hmmm........ in what I've read about utilizing bandpassed rear fill its been recomended to use a mono versus stereo signal, but maybe there wouldn't be that much difference.

However, doesn't a lot of today's music have material in the 120-250 Hz range recorded in stereo? Wouldn't I be losing some of this information by utilizing only one channel? I may not be able to tell the difference between a stereo and mono signal off the 6w0's in the rear, but it seems a left to right percussion sequence for example might not sound right w/o information from both channels present.

Well I guess if it won't "damage" anything I can try both methods and if need be get hold of another 1.1i although that might be overkill for a simple rear fill application.

thanks kiki

-Fishy

ah yeah rear fill. forgot.
for that, you want to use ~500Hz to 5KHz as a notch filter.
recordings cease to separate stereo at around 250Hz, so no you're not going to lose anything, and stereo separation on rear speakers will actually ruin your imaging in the front.

what I'd do is bridge a two channel amp and wire your two speakers in series.
that way you run L/R inputs to the amp but the rear fill channels are mono output with teh same power you'd get running them in stereo anyway.

Yeah, I originally had a Soundstream Class A 50II bridged to some rear 5 1/4's in series, but the amp had problems with an output(or input) on one side and periodically "lost power". I'm incredibly limited on space and have found only 4 amplifiers that I can easily(and stealthily, lol, that a word?) incorporate in my system: Soundstream's old class A 50, D60, and D100 models and this baby Xtant.

The problem with all these amps is they utilize only one rca input for mono operation so I was faced with the same "stereo to mono" conundrum regardless of which I chose. There are ways I can get around this. My PPI frx456 has "summed" sub outs and I was utilizing one of my 1001dx's high pass outs(80 Hz) with the frx456's low pass set at around 250 to create a bandpass signal. Needless to say this resulted in a tuning nightmare especially since these older Soundstream amps weren't designed for today's high voltage line levels.

I love my crossover,

http://www.directed.com/guides/manuals/ ... 0_3-03.pdf

(thats it minus the 12 db input attenuation option) and have it mounted in my Explorer's center console for easy "on the fly" tweaking from the listening position. As you can see the thing is extremely versatile and at 400 dollars a pop was considered one of the best units of its time.

I'd like to keep it and if you know where I can find a schematic for a simple summing circuit I'm not opposed to building one. I've got some op amp IC's laying around and figure I could just use a simple voltage divider to get 5 volts Vcc. Might be a fun project if the y-connector thing won't work.

Wow, maybe this did get too complicated, but thats part of the fun.



-Fishy

Ahh nevermind, I found a summing amp circuit,

http://webpages.ursinus.edu/lriley/ref/ ... 0000000000

and I don't need a voltage divider. Here's my op amps:

http://focus.ti.com/lit/ds/symlink/ne5532.pdf

Its been awhile since I messed with this stuff. It should work just fine off 12 volts, but I'm not sure how to get -12 volts (-Vcc). I always thought you simply hooked -Vcc to ground. I think this may be over my head and I'll just do the y-connector or one channel thing and hope for the best, hehe.

-Fishy

KikiTheCat wrote:ah yeah rear fill. forgot.
for that, you want to use ~500Hz to 5KHz as a notch filter.
recordings cease to separate stereo at around 250Hz, so no you're not going to lose anything, and stereo separation on rear speakers will actually ruin your imaging in the front.

what I'd do is bridge a two channel amp and wire your two speakers in series.
that way you run L/R inputs to the amp but the rear fill channels are mono output with teh same power you'd get running them in stereo anyway.

Cease to seperate stereo at around 250hz?

I don't know of a frequency cutoff for stereo operation, neither high nor low?