On 5 Feb 2003 21:11:51 -0800, geneticallymutant@hotmail.com (JBorg, Jr.) wrote:

>> I seriously doubt a Y connector would make any difference in the

>> sound, especially not compared to the big difference adding a

>> subwoofer will make.

[Y at tape out]

>I'm just gonna have to disagree here Neil. Having the Y connector

>betw preamp and pwr amp, which is my current set-up, has its disadvantages.

>Without the Y connectors, images are sharper and much more palpable.

>There are many more but these are the first things that I would notice-

>as I have switch back n forth with n without the Y's many times before.

[...........]

I used to design, build, and sell LARGE subwoofers

(ones that really did what the others only promised ;-).

See: http://www.David-Ruether-Photography.com/Audio.html.

Some comments:

- If you "Y" off either the tape out (no volume/tone

control) or off the preamp line out and directly

combine one set of outputs to feed a mono subwoofer,

you will force the preamp channels to mono (and this

can damage the preamp, depending on its design).

- If there is a series resistor before the outputs

of the preamp, and/or at the sub (stereo) inputs,

the size of the resistor will determine the amount

of stereo lost with the connections (but even fairly

small values may protect the preamp).

- You can add resistors to the legs of the "Y" adapters

that go to the subwoofer (try 5k on each to start).

- If there are ANY electronics within the sub box in

series with the preamp-amp connectors (even a single

high-quality capacitor in series with the power

amp), the sound of the main speakers with the sub

turned off will change - generally for the worse

(even with a big enough cap to start cutting response

well below the speakers lower limit, even if the cap

is paralleled with small high-quality caps to improve

their high-end response...), so with very detailed

speakers (many electrostatics are), you can easily

hear the effect of the series electronics and may want

to avoid them.

- Sub placement is critical, though good sub output is

omnidirectional. Poor placement can result in very

uneven response and can also spoil directional info of

well-placed high-quality main speakers.

- With my sub designs, I used two methods of crossing

over between the sub and the main speakers: the common

one of building a high-quality 12db/octave low-cut

pair for the main speakers, combined with a soft-edged

24db/octave summing/EQing/level-control crossover for

the sub (works well for most systems); or, a direct

connection of the preamp line out with the main-speaker

amps inputs (no crossover for these - they roll off

by themselves, which is why the sub is desired...;-),

with an adjustable angle 36db-ultimate, soft-corner-

start EQ/response-rotate/level-adjust "crossover" for

the bass, which permits blending of the sub into the

main speaker output without electronically disturbing

them.

- Even with this arrangement, subtle shifts in the sub

output-level/response-shape can effect the audio balance

all the way to the highest frequencies of the main

speakers (I never came up with a good explanation for

this...), so the adjustment must be done with great

care (this can take several days to get it right - but

when you do, the original excellent sound has the

benefits of the addition of the lower frequencies).

- Done right, a sub adds subjectively higher sound

levels to the same levels previously used, adds

"solidity" and "excitement" without "boom" or

"bluddle-luddle" effects, and even the background

"air" of recordings with little real bass sounds

better-balanced. And, a good sub set-up NEVER makes

you aware of the sub as a sound source...

- Done wrong, adding a sub is worse than not...