Hey audiophiles, help me out to hook up Yamaha A-S801 to the speakers and to set correct impedance.

Arthur Vin

Arthur Vin

Enthusiast
I'm confused about the impedance, help me out guys!
Just got my Yamaha A-S801 + two Polk TSx 550T Towers + Polk PSW505 powered SUB.
TSx 550T as well as A-S801 has bi-wiring option to drive tweeters+mids and woofers independently - I definitely want this.
1) TSx 550T is 8 Ohms and A-S801 Impedance selector has two positions (see the picture):
LOW
A or B: 4ohm Min /SPEAKER
A + B: 8ohm Min /SPEAKER
HIGH
A or B: 6ohm Min/SPEAKER
Which position will be correct for bi-wired connection?

2) A-S801 speaker modes A + B and Bi-wiring - Are they both technically the same for the AMP?
And how the Amp knows how to distribute the frequencies in bi-wiring mode or it's built-in speaker filter responsibility?

3) Yamaha A-S801 will output full range to both channels even if SUB is connected and I need to keep SUB low pass away from 100Hz.
But the problem is that Sub which is connected trough the single RCA will bypass Subs low pass filter knob, and it's AMP responsibility to distribute it correctly. But as I understood A-S801 Sub Out is fixed at <=100Hz and cannot be changed. So how can I control low pass for Sub, any options?
20160723_180608.jpg
 
lovinthehd

lovinthehd

Audioholic Jedi
First, just owning the gear and seeking answers qualifies you as an audiophile.

Passive bi-amping and bi-wiring from a single avr/amp is just window dressing, not worth the extra wire really. You're still operating off the same power supply and still limited by the passive components in your speaker's crossover network.

Your manual just shows a "cut-off" of 100hz, no info on slope that I saw. You may be able to use a sub's low pass filter to "blend" a crossover. I'd try your sub's LPF 100hz setting, maybe 80, maybe 120....

ps Looked at your speakers, probably try a lower LPF setting on your sub, range 40-60 perhaps but some like extra mid bass....
 
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Arthur Vin

Arthur Vin

Enthusiast
1) Here's what sub-woofer manual says:
20160723_230850.jpg

As you can see the low pass filter doesn't work in LFE case.

2) Impedance question remains unanswered.
What's the correct impedance switch position without bi-wiring?
And with bi-wiring, I just want to understand how this thing works. A and B are in parallel so that means that impedance will drop to 4 ohm? Is that correct?

3) Also as you can see Sub have speaker wire input/output. What if I connect Amp B output to Sub speaker-In and then Subs speaker-out to tower speaker bottom terminals. While Amp A speaker output still goes to tower speakers upper terminal. In this case low pass filter on Sub will work but will this count as bi-amping?
71SoiMZf6kL._SL1500_.jpg
 
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lovinthehd

lovinthehd

Audioholic Jedi
1/ Using the LFE input on a sub often disables the low pass filter, sometimes you need to maximize the setting on the sub. LFE means in the case of your sub that it will simply use the LPF provided by the receiver, but you don't have bass management other than the vague low pass "cutoff" of 100hz provided by your integrated amp; you don't have a high pass filter for your speakers. If you don't want to use the LFE input use the line input instead of the LFE and adjust the low pass filter manually.

2/ The lower impedance switch simply limits the unit, leave it at 8 is the general advice. Gene in his review of this unit mentions "Leave it at its factory default ‘high’ setting regardless of the speakers you connect, or else you will be starving your speakers of power just to validate a UL heat dissipation test that is required to list 4-ohm capability on the silkscreen". Gene also covers the A&B impedance thing.

3/ Some subs can apply a high pass filter thru their line level or high level connections....don't know about yours. Still passive bi-amping from a single power supply/same amp with passive components connected, waste of wire IMO; just marketing for the most part rather than something of audible value IMO.

Just connect your speakers to A and blend your sub in as you're able. What sub is it?

ps Polk 505, don't see anything in the manual about any high pass filter feature for your speakers using the speaker level inputs.
 
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Arthur Vin

Arthur Vin

Enthusiast
If you don't want to use the LFE input use the line input instead of the LFE and adjust the low pass filter manually.
You mean to connect Amp Sub out via RCA splitter to Sub Line In L and R?

2/ The lower impedance switch simply limits the unit, leave it at 8 is the general advice. Gene in his review of this unit mentions "Leave it at its factory default ‘high’ setting regardless of the speakers you connect, or else you will be starving your speakers of power just to validate a UL heat dissipation test that is required to list 4-ohm capability on the silkscreen". Gene also covers the A&B impedance thing.
HIGH setting is 6 ohm/speaker, not 8, but speakers are 8 ohm. The only 8 ohm setting is available in LOW setting for A+B setup.
 
Arthur Vin

Arthur Vin

Enthusiast
I've been contacted by my physics professor, whom I sent this question a week ago. He said that I need to keep it in LOW setting for A+B (4 x 8ohm speakers) or bi-wiring (2 x 8ohm bi-wired speakers)
and switch to HIGH setting if it's just A or just B alone with 2 x 8ohm speakers. Which makes sense now.
 
lovinthehd

lovinthehd

Audioholic Jedi
You mean to connect Amp Sub out via RCA splitter to Sub Line In L and R?


HIGH setting is 6 ohm/speaker, not 8, but speakers are 8 ohm. The only 8 ohm setting is available in LOW setting for A+B setup.
You can use just L or R, altho using a splitter is okay too.

You have a 2ch amp, not a 4 ch amp, suggest A for main room, B for a second room and use volume control judiciously if using A and B together due to impedance. Usually the higher impedance setting is labeled 8 on most avrs.
 
lovinthehd

lovinthehd

Audioholic Jedi
I've been contacted by my physics professor, whom I sent this question a week ago. He said that I need to keep it in LOW setting for A+B (4 x 8ohm speakers) or bi-wiring (2 x 8ohm bi-wired speakers)
and switch to HIGH setting if it's just A or just B alone with 2 x 8ohm speakers. Which makes sense now.
He may understand physics....but seems to believe inarketing nonsense...imho.
 
Arthur Vin

Arthur Vin

Enthusiast
He may understand physics....but seems to believe inarketing nonsense...imho.
Well, he's probably not a sound tech, but still he got the physics right, it perfectly make sense:
2 x 8ohm speakers per channel gives you a total impedance of 4ohm:
And if you look at Amp label:
LOW
A or B: 4ohm Min /SPEAKER
A + B: 8ohm Min /SPEAKER

It just confirms that calculation, either one 4 ohm speaker per channel
OR
two 8 ohm speakers per channel.

I don't know about you guys, but I believe in science and not religion. :D
 
lovinthehd

lovinthehd

Audioholic Jedi
Well, he's probably not a sound tech, but still he got the physics right, it perfectly make sense:
2 x 8ohm speakers per channel gives you a total impedance of 4ohm:
And if you look at Amp label:
LOW
A or B: 4ohm Min /SPEAKER
A + B: 8ohm Min /SPEAKER

It just confirms that calculation, either one 4 ohm speaker per channel
OR
two 8 ohm speakers per channel.

I don't know about you guys, but I believe in science and not religion. :D
The bi wiring isnt science nor using your 2 ch amp with less than ideal impedance loads as if it were 2 seperate amps/power supplies, let alone with passive xover components in the speakers....marketing rather than science. Just sayin'.....
 
Arthur Vin

Arthur Vin

Enthusiast
The bi wiring isnt science nor using your 2 ch amp with less than ideal impedance loads as if it were 2 seperate amps/power supplies, let alone with passive xover components in the speakers....marketing rather than science. Just sayin'.....
Are you sure about marketing trick?
Consider following setup:
2 x 16 Ohm Marshall cabinets + Marshall 100W Tube Head. (impedance switch has 4, 8 and 16)
Since cabs are in parallel Amp must be set to 8 Ohm impedance.
I've gone trough blown output transformer replacement because I forgot to switch impedance back to 8ohm when I returned back to home from studio and drove those cabs for few months with Amp set to 16Ohm.
At home I drive both cabs, in studio just one.

I didn't brought this earlier because tube amps have different weak points compared to solid state/ transistors.
 
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lovinthehd

lovinthehd

Audioholic Jedi
Are you sure about marketing trick?
Consider following setup:
2 x 16 Ohm Marshall cabinets + Marshall 100W Tube Head. (impedance switch has 4, 8 and 16)
Since cabs are in parallel Amp must be set to 8 Ohm impedance.
I've gone trough blown output transformer replacement because I forgot to switch impedance back to 8ohm when I returned back to home from studio and drove those cabs for few months with Amp set to 16Ohm.
At home I drive both cabs, in studio just one.

I didn't brought this earlier because tube amps have different weak points compared to solid state/ transistors.
Tube and solid state amps are a bit different as are musicians' monitors (single driver, no crossover network, correct?) but still needs another amp it sounds like...

ps bi-wiring for a single speaker composed of two or more drivers connected by a passive crossover network is what I mean by marketing rather than science. Just sells more wire really. Why exactly do you keep thinking of doing this with your speakers?
 
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lovinthehd

lovinthehd

Audioholic Jedi
One further thought for you. The speaker having a high and low set of terminals for passive bi-wiring or passive bi-amping is marketing.
 
Arthur Vin

Arthur Vin

Enthusiast
One further thought for you. The speaker having a high and low set of terminals for passive bi-wiring or passive bi-amping is marketing.
Why? You can hook up a second A-S801 to the lower terminals and you've got bi-amped setup. If terminals are not wired properly then it's not marketing but rather fraud.
 
lovinthehd

lovinthehd

Audioholic Jedi
Why? You can hook up a second A-S801 to the lower terminals and you've got bi-amped setup. If terminals are not wired properly then it's not marketing but rather fraud.
Why on earth would someone buy another S801 to do this? For what benefit?

Are you assuming that because there are hi/lo terminals available on your speaker that it is meaningful?
 
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