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Connecting unbalanced Subwoofer to Balanced System? How?

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Anonymous
March 26, 2005 3:12:17 PM

Archived from groups: rec.audio.pro (More info?)

I have balanced TRS coming out of my Mackie to my Bryston power amplifier
and then to my KRK monitors.

I would like to add a Velodyne DPS-12 Sub which supposedly has RCA inputs
a long with "Speaker level" inputs.

http://www.circuitcity.com/rpsm/oid/97737/rpem/ccd/prod...

What would be the best way to connect this thing and what would be the
tradeoff? I'm assuming using the speaker outputs from my Bryston but then
wouldn't the amp in the sub be driving everything?

tia for any advice.
--
Steve Glenn
Anonymous
March 26, 2005 8:01:56 PM

Archived from groups: rec.audio.pro (More info?)

Steve Glenn <sgo1960@yahoo.com> wrote:
>I have balanced TRS coming out of my Mackie to my Bryston power amplifier
>and then to my KRK monitors.
>
>I would like to add a Velodyne DPS-12 Sub which supposedly has RCA inputs
>a long with "Speaker level" inputs.
>
>http://www.circuitcity.com/rpsm/oid/97737/rpem/ccd/prod...
>
>What would be the best way to connect this thing and what would be the
>tradeoff? I'm assuming using the speaker outputs from my Bryston but then
>wouldn't the amp in the sub be driving everything?

Sure, but the sub already has a low-pass filter in it. The problem is that
you need a high-pass filter on the mains.

You might look into something like the Rane AC-22 which is probably the
cheapest crossover I'd recommend. You'll need to sum the two LF outputs
and run them to the sub.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
March 26, 2005 10:05:15 PM

Archived from groups: rec.audio.pro (More info?)

"Steve Glenn" <sgo1960@yahoo.com> wrote in message
news:3aljffF6b59vqU1@individual.net...
>
> I have balanced TRS coming out of my Mackie to my Bryston power amplifier
> and then to my KRK monitors.
>
> I would like to add a Velodyne DPS-12 Sub which supposedly has RCA inputs
> a long with "Speaker level" inputs.
>
> http://www.circuitcity.com/rpsm/oid/97737/rpem/ccd/prod...
>
> What would be the best way to connect this thing and what would be the
> tradeoff? I'm assuming using the speaker outputs from my Bryston but then
> wouldn't the amp in the sub be driving everything?
>
> tia for any advice.
> --
> Steve Glenn
>

Hi Steve,

You can try what I do what I do but keep in mind it's probably not the
'preferred method, although it sounds pretty good to me. ( so, YMMV etc )

I have a Tannoy PS115 powered sub that I use with a pair of KRK V8's ( self
powered too ). The KRK's have balanced inputs but the Tannoy only has
unbalanced. I haven't tried it in a long time but when I did I didn't like
the way the KRK's sounded running off of the Tannoy's crossover output, so
now I :

use XLR 'Y' cables to split the signal ( someday I'll wire my patch bay . .
.. )
the KRK's are hooked to one pair of the 'Y' and the other goes to an ART
CleanBox which converts the balanced to unbalanced
:http://www.bswusa.com/proditem.asp?item=CLEANBOX
the output of the clean box goes to the Tannoy sub

Since the KRK's don't have a lot in the way of low end ( sort of naturally
high passed ) I just adjust the crossover frequency on the Tannoy to only
makeup for the range that KRK's are lacking in. One advantage of doing
things this way is that I can easily turn the sub off and listen to the KRK
by themselves when I want to without repatching anything. ( I'm sure others
here will point out the disadvantages! ;-)

Best of luck!

John L Rice
Related resources
Anonymous
March 26, 2005 10:42:10 PM

Archived from groups: rec.audio.pro (More info?)

In article <3aljffF6b59vqU1@individual.net> sgo1960@yahoo.com writes:

> I have balanced TRS coming out of my Mackie to my Bryston power amplifier
> and then to my KRK monitors.
>
> I would like to add a Velodyne DPS-12 Sub which supposedly has RCA inputs
> a long with "Speaker level" inputs.
>
> What would be the best way to connect this thing and what would be the
> tradeoff? I'm assuming using the speaker outputs from my Bryston but then
> wouldn't the amp in the sub be driving everything?

Why don't you look in the manual when you get the speaker? Usually
these things have a crossover network (I assume it's a powered
subwoofer) that you feed with full range audio, and it has outputs to
go to the power amplifier that are high-pass filtered to keep the lows
out of your main speakers. I wouldn't worry that those are RCAs and
just feed them from the Mackie mixer, then send the "mains" outputs to
the power amplifier for your KRKs.



--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
March 27, 2005 12:02:01 AM

Archived from groups: rec.audio.pro (More info?)

On Sat, 26 Mar 2005 19:42:10 -0500, Mike Rivers wrote:

>
> In article <3aljffF6b59vqU1@individual.net> sgo1960@yahoo.com writes:
>
>> I have balanced TRS coming out of my Mackie to my Bryston power amplifier
>> and then to my KRK monitors.
>>
>> I would like to add a Velodyne DPS-12 Sub which supposedly has RCA inputs
>> a long with "Speaker level" inputs.
>>
>> What would be the best way to connect this thing and what would be the
>> tradeoff? I'm assuming using the speaker outputs from my Bryston but then
>> wouldn't the amp in the sub be driving everything?
>
> Why don't you look in the manual when you get the speaker? Usually
> these things have a crossover network (I assume it's a powered
> subwoofer) that you feed with full range audio, and it has outputs to
> go to the power amplifier that are high-pass filtered to keep the lows
> out of your main speakers. I wouldn't worry that those are RCAs and
> just feed them from the Mackie mixer, then send the "mains" outputs to
> the power amplifier for your KRKs.

Actually I looked at the manual online and it is not clear as to how it
works.
It appears there are a number of ways of hooking it up, only one of which
*might* apply to me.

I have a Mackie running balanced TRS 1/4 inch out to my Bryston.
According to the Velodyne manual, I can either use a line in or connect my
current amplifier to a different set of inputs on the subwoofer designed
to properly load and deal with my amplifier.
Suppose I connect my speaker outs on the Bryston via 2 conductor zip cord
to the Velodyne, my question is what amplifier is driving what speakers?
Is my Bryston being crossed over at speaker level to my KRK? and the
internal Velodyne amp driving the Subwoofer?


Let's suppose I use the UN-balanced Outs from the Mackie to the RCA Line
Level inputs on the Velodyne.
How do I connect the Line OUTPUTS of the Velodyne to my Bryston which is
looking for TRS connectors and a signal at +4 ?

Here is a link to the manual:

http://www.velodyne.com/velodyne/products/product.aspx?...

TIA to Scott/Mike and anyone who can offer advice.

--
Steve Glenn
Anonymous
March 27, 2005 5:29:12 AM

Archived from groups: rec.audio.pro (More info?)

On Sat, 26 Mar 2005 20:02:01 -0500, Steve Glenn <sgo1960@yahoo.com>
wrote:

>I have a Mackie running balanced TRS 1/4 inch out to my Bryston.
>According to the Velodyne manual, I can either use a line in or connect my
>current amplifier to a different set of inputs on the subwoofer designed
>to properly load and deal with my amplifier.
>Suppose I connect my speaker outs on the Bryston via 2 conductor zip cord
>to the Velodyne, my question is what amplifier is driving what speakers?
>Is my Bryston being crossed over at speaker level to my KRK? and the
>internal Velodyne amp driving the Subwoofer?

Yes. The speaker level inputs on powered subwoofers are just
for convenience; they are padded down to line level, then
combined with the "line" inputs, then lowpass-filtered and
amplified.

Speaker level *outputs* can vary a bit, but are generally
just a single series electrolytic capacitor; kinda spotty.

If, after trying the consumer quality crossovering included,
you're not happy, a real electronic crossover is next up.

Or, a homebrew two pole passive line level high-pass is pretty easy.
Just a few R's and C's.

Good fortune,

Chris Hornbeck
Anonymous
March 27, 2005 2:37:54 PM

Archived from groups: rec.audio.pro (More info?)

John L Rice <Drummer@ImJohn.com> wrote:
>
>Since the KRK's don't have a lot in the way of low end ( sort of naturally
>high passed ) I just adjust the crossover frequency on the Tannoy to only
>makeup for the range that KRK's are lacking in. One advantage of doing
>things this way is that I can easily turn the sub off and listen to the KRK
>by themselves when I want to without repatching anything. ( I'm sure others
>here will point out the disadvantages! ;-)

The problem with this is that the KRKs are still getting low end signal that
they can't reproduce. That restricts your dynamic range and it means you
get more distortion than you should otherwise get. If you believe doppler
effect is a problem (and I am staying out of that thread), it's an issue
here.

Also, the drop-off of the KRKs on the bottom end is probably not the same
slope as the low-pass filter on the subs!
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
March 27, 2005 11:25:08 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news:D 26k0i$dap$1@panix2.panix.com...
> John L Rice <Drummer@ImJohn.com> wrote:
>>
>>Since the KRK's don't have a lot in the way of low end ( sort of naturally
>>high passed ) I just adjust the crossover frequency on the Tannoy to only
>>makeup for the range that KRK's are lacking in. One advantage of doing
>>things this way is that I can easily turn the sub off and listen to the
>>KRK
>>by themselves when I want to without repatching anything. ( I'm sure
>>others
>>here will point out the disadvantages! ;-)
>
> The problem with this is that the KRKs are still getting low end signal
> that
> they can't reproduce. That restricts your dynamic range and it means you
> get more distortion than you should otherwise get. If you believe doppler
> effect is a problem (and I am staying out of that thread), it's an issue
> here.
>
> Also, the drop-off of the KRKs on the bottom end is probably not the same
> slope as the low-pass filter on the subs!
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

Thanks for the info Scott. And maybe there is even some cancellation/comb
filtering of low frequencies since the sub is behind the mains and 5 feet
away from the left one and 8 feet away from the right one? ( or not? )
Maybe my monitoring system is screwed up in just the right way so that it
perfectly compensates for how screwed up my room is tuned? ( I know . . .
..dreaming here . . . )

I've long thought about getting a really good crossover ( and possible
external power amp for the sub ) but now that is on hold since I was laid
off a few weeks ago from my day job and I recently ignored all common sense
and bought some real expensive converters.

--
John L Rice
Drummer@ImJohn.com
Anonymous
March 28, 2005 2:00:55 PM

Archived from groups: rec.audio.pro (More info?)

John L Rice <Drummer@ImJohn.com> wrote:
>
>Thanks for the info Scott. And maybe there is even some cancellation/comb
>filtering of low frequencies since the sub is behind the mains and 5 feet
>away from the left one and 8 feet away from the right one? ( or not? )
>Maybe my monitoring system is screwed up in just the right way so that it
>perfectly compensates for how screwed up my room is tuned? ( I know . . .
>.dreaming here . . . )

There's always some cancellation, but the idea is that you use a sharp
crossover slope to minimize it, and you move the sub around to minimize
it even more.

Play a sweep tone and listen to it. If it sounds like it's pretty much
the same level as it sweeps from 20 to 200 Hz, don't worry about it.

>I've long thought about getting a really good crossover ( and possible
>external power amp for the sub ) but now that is on hold since I was laid
>off a few weeks ago from my day job and I recently ignored all common sense
>and bought some real expensive converters.

Did you buy enough converters that you have a spare D/A channel for the
sub, allowing you to do the crossover with a cheap digital filter?
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
March 28, 2005 2:00:56 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news:D 29677$da0$1@panix2.panix.com...
> John L Rice <Drummer@ImJohn.com> wrote:
>>
>>Thanks for the info Scott. And maybe there is even some cancellation/comb
>>filtering of low frequencies since the sub is behind the mains and 5 feet
>>away from the left one and 8 feet away from the right one? ( or not? )
>>Maybe my monitoring system is screwed up in just the right way so that it
>>perfectly compensates for how screwed up my room is tuned? ( I know . . .
>>.dreaming here . . . )
>
> There's always some cancellation, but the idea is that you use a sharp
> crossover slope to minimize it, and you move the sub around to minimize
> it even more.
>
> Play a sweep tone and listen to it. If it sounds like it's pretty much
> the same level as it sweeps from 20 to 200 Hz, don't worry about it.

Well, no matter what speaker setup I use ( sub or no sub ) the volume of the
sweep is all over the place. ;-( Somesay I'll attempt to fix the room or
move the studio to a proper room.

>>I've long thought about getting a really good crossover ( and possible
>>external power amp for the sub ) but now that is on hold since I was laid
>>off a few weeks ago from my day job and I recently ignored all common
>>sense
>>and bought some real expensive converters.
>
> Did you buy enough converters that you have a spare D/A channel for the
> sub, allowing you to do the crossover with a cheap digital filter?
> --scott
>
>

I never thought about using a digital filter to cross over but I don't think
that would be that practical for me since I don't always run everything
through the computer ( like if I'm listening to a CD, DAT or cassette etc ).
I only got one D/A pair. I wanted to get more but they are expensive so in
the future I'll hopefully get another pair or two.

John L Rice
!