Sub power amp and phase problems (1 Viewer)

[SteveEdwards]

I have an HK PA5800 5-channel amp. Three channels go to my front three speakers, the other two go to my Shiva subwoofer.
My main speakers are little bookshelf speakers (Avance Epsilon 910's), so I want to run them on the 'small' setting. When I do this, the upper base fades and muddies away. This is what a phase adjustment is for, is it not? The problem is, I don't have one since I'm running a power amp and not a 'real' subwoofer amplifier.
How is this corrected?
I have one speaker on top of the subwoofer, the other on top a stand. I can't put the subwoofer between the speakers because that causes shielding problems with my TV.
Thanks for the help guys, as usual!
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-Stretch

 

[Patrick Sun]

Whelp, if you just want to check and see if running the sub out of phase with the speakers, than just flip flop the positive and negative terminal on each voice coil going to the sub. That will put you 180 degree out of phase with the speakers.
But I don't really think this is your problem. When you run the speakers as "small" the receivers will cut off (as in sloping) the low frequencies depending on a set value, or, if you're lucky, a variable value that you can control. If the sub only plays up to frequencies around 80Hz before slopping off, but the receiver's "small" speaker setting is sloping off frequencies under 120Hz, then you'll hear a hole in the upper bass response.
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PatCave; HT Pix; Gear; DIY Mains; DIY CC; Sunosub I + II + III; DVDs; Link Removed

 

[SteveEdwards]

I have a Denon AVR1700 receiver... I'd hope a Denon receiver would be smarter than that!
Besides, the midbass sounds nice if I disconnect the amplifier, but still fool the receiver into thinking it's there.

 

[Patrick Sun]

Denon's usually have a fixed bass slope-off around 90Hz or 80Hz when you select the front speakers as "small".
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PatCave; HT Pix; Gear; DIY Mains; DIY CC; Sunosub I + II + III; DVDs; Link Removed

 

[SteveEdwards]

Is there anything available along the lines of a subwoofer preamp that would have mainly variable phase and gain controls? Nothing expensive, all I really want is the variable phase control...

 

[Julian Data]

The only product I know of are plate amps that have the phase. Although, I don't know if Paradigm's X-30 has phase implementation.
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[SteveEdwards]

Euraeka! Good suggestion, it does have phase control- this is probably exactly what I need.
I think though, at ~$110, I'd still rather just get a plate amp for $170 from Adire. Decisions, decisions...

 

[Julian Data]

Whoa! It does have it? Wow.. Shocker!
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[SteveEdwards]

Yeah, it has variable phase, gain, and crossover settings, with high-pass outputs selectable at 50, 80, or 120hz. Nice! But I think for its price, getting a plate amp is still a better deal.

 

[Julian Data]

Hey Steve,
I agree with you.
jd
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