Bryston SP1.7 Subwoofer out question

Levi · « **on:** 13 Jul 2004, 10:29 pm »

I purchased a second subwoofer. Can I use both balanced and single-ended subwoofer output simultaneously? Please let me know best practices in how I can hook up a secondary subwoofer in my Bryston SP1.7?

James Tanner · « **Reply #1 on:** 14 Jul 2004, 05:36 pm »

Hi,

Yes the RCA and XLR have the same signal out.

james

jethro · « **Reply #2 on:** 14 Jul 2004, 08:41 pm »

Levi,

Depending on the type of sub, you might have to adjust the gain downward on the sub using the balanced connection (or vice versa). Active subs shouldn't be a problem but if you have passive subs then I believe you will need an amp with adjustable gain such as the ST-Pro series or some of the SST amps which I believe have some discrete gain settings.

Levi · « **Reply #3 on:** 16 Jul 2004, 04:05 pm »

I got the idea. I have implemented 2 subs with Bryston SP1.7. One using the single-ended and the other balanced. It never occured to me how much bass clarity I gained buy utilizing two subs. Cheers

If one has the system capability and space...I would suggest to give it a try.

ec · « **Reply #4 on:** 18 Jul 2004, 04:24 pm »

I am actually using three subs with the SP 1.7. You may have seen my old post asking for graphed freq responses of PMC speakers that started this journey. I used all balanced connections to the Bryston power amps except for channel 6 & 7 where I have no choice but to use unbalanced.

Balanced Sub output > Crown power amp powering a passive sub
Unbalanced Sub output > Def Tech SuperCube Active Sub
Front L&R unbalanced > Velodyne HGS 12 series II - this allows me to set my speakers to large and also enjoy full range audio when listening in two channel bypass.

And yes I do plan to get more subs (passive ones though)

Levi · « **Reply #5 on:** 18 Jul 2004, 11:56 pm »

Excellent sub setup! Two subs are better than one. Three subs must be awesome!

Quote from: ec

I am actually using three subs with the SP 1.7. You may have seen my old post asking for graphed freq responses of PMC speakers that started this journey. I used all balanced connections to the Bryston power amps except for channel 6 & 7 where I have no choice but to use unbalanced.

Balanced Sub output > Crown power amp powering a passive sub
Unbalanced Sub output > Def Tech SuperCube Active Sub
Front L&R unbalanced > Velodyne HGS 12 series II - this allows me to set my speakers to large and ...

Adz523 · « **Reply #6 on:** 30 Jul 2004, 12:22 am »

Any differences between eithe using the balanced output or a Y connector into the RCA input for hooking up that second subwoofer?

ec · « **Reply #7 on:** 30 Jul 2004, 12:37 am »

Quote from: Adz523

Any differences between eithe using the balanced output or a Y connector into the RCA input for hooking up that second subwoofer?

You will split the signal gain if using a Y connector whereas you won't using a balanced and unbalanced connection. The Y connector is also available for balanced connections All other rules still apply, ie you have to properly set the levels for the sub(s). Only a handful of active subs use a balanced connections though

Adz523 · « **Reply #8 on:** 30 Jul 2004, 12:40 am »

I am using Def Tech speakers with built-in subs. I do not think they can have a balanced interconnect. If that's the case, what are all my options?

ec · « **Reply #9 on:** 30 Jul 2004, 04:03 am »

If you have a power amp with balanced inputs which you do - use those. The power amp is connected using its (L & R) balanced inputs. The power amp then feeds the Def Techs via the normal speaker connections / terminals. Use the unbalanced outputs (L & R) from the Bryston SP 1.7 to feed the sub portion of the Deftechs. Make sure you set the speakers to large on the SP 1.7. You will be using both the balanced and unbalanced outputs from the SP 1.7 and only the balanced inputs on the 6B SST.

edited for clarity.

Adz523 · « **Reply #10 on:** 30 Jul 2004, 09:22 am »

Interesting...so run interconnect cables from the L&R balanced inputs on my 6b sst to the balanced outputs on my 1.7; and then run my subwoofer cables from the speakers into the left and right unbalanced outputs on the 1.7? Can the amp really use both balanced and unbalanced outputs at the same time? I'll also need two new interconnect cables.

ec · « **Reply #11 on:** 30 Jul 2004, 04:51 pm »

I have edited my previous post to make explain things more explicity.

jimmyp58 · « **Reply #12 on:** 30 Jul 2004, 10:33 pm »

Eric:

I have a question on your response to ADZ. I follow what you are saying but my pea-brain isn't comprehending something so I hope you can explain further. I get the part about the balanced cables...that's straightforward. I am confused about the next part. I am interpreting what you are saying in that ADZ should take the unbalalanced L&R outs from his SP 1.7 and send one to each of his Def Tech 7000's sub inputs. But wouldn't that be sending a full signal rather than a .1 (which the sub out on the 1.7 would do?

Please explain for me.

Thanks...

Jim

ec · « **Reply #13 on:** 31 Jul 2004, 02:56 am »

Jim,

Correct, a full range signal will be sent to the sub on the Def Techs. I trust there is a crossover (adjustable) on the sub portion of the Def tech that will filter out everything above say 80 Hz. I am not familiar with these specific speakers but I do own a Def Tech SuperCube II sub which definitely has adjustable gain and cross over points. At one time I did feed a full range signal to the SuperCube II and adjusted the cross over on this sub accordingly. The SuperCube II has been relegated to be an expensive bass shaker (long story) and has been replaced by a Velodyne HGS 12 II running the same configuration (unbalanced outputs from the Bryston SP 1.7 to to the "full range" L & R inputs on the Velodyne).

So there are two scenarios that are possible:

1. Using the Def Techs with the built in subs only (no seperate dedicated sub)

In this first scenario, I would set ths SP 1.7 like so:
L&R = large
Centre =small
Surrounds = small
Rears = small
Sub = NO

The .1 info will be sent to the L & R speakers. Others may recommend sending the sub output to the integrated subs and setting the L&R to small and sub=yes. I personally would not do this because when listening in two channel bypass mode, you will not get a full range sound from the L&R speakers. Just a personal preference.

2. Using the Def Techs with the built in subs with a seperated dedicated sub(s)

In the second scenario, I would set ths SP 1.7 like so:
L&R = large
Centre =small
Surrounds = small
Rears = small
Sub = Yes

I have three seperate subs and from my experimentation the above setup (scenario 2) works best for my listening preferences. The only difference is that my PMC speakers do not have an integrated sub but the Velodyne HGS 12 is acting like an integrated sub.

jimmyp58 · « **Reply #14 on:** 31 Jul 2004, 03:08 am »

Thanks for clearing this up Eric. I had it right but forgot about the crossover! I told you I had a pea brain!!!

Jim

James Tanner · « **Reply #15 on:** 1 Aug 2004, 04:24 pm »

Just a quick point - the Balanced (XLR) and the Unbalanced (RCA) outputs on the SP1.7 are the same gain to avoid issues when using combinations of both.

james

James Tanner · « **Reply #16 on:** 1 Aug 2004, 04:29 pm »

Another point - all rooms react differently but be careful when utilizing multiple subs.
See my newsletter -

http://www.bryston.ca/newsletters/57_files/vol5is7.html

james

jimmyp58 · « **Reply #17 on:** 1 Aug 2004, 09:03 pm »

I know what you mean James r.e. using two subs and how the sound can differ regarding their placement. It took me considerable time to find the best spot(s) with my Rotel RSP-1098. But once I found it, it produced a very desireable response. Who knows, with my 1.7 I may have to do more tinkering around and perhaps may only need one sub versus two.

The reason I went with two is that my HT is relatively long (~34 feet). It seemed that I was bass heavy in the front no matter where I placed the sub (some locations were boomier than others). So, I picked up a second sub and took great care calibrating both and now I have a deep, lush, quick, and dispersed bass response throughout my room.

Jim

James Tanner · « **Reply #18 on:** 2 Aug 2004, 11:50 am »

Hi Jim,

Great - sounds like you did it correctly. The point to remember here is that in the recording studio the .1 channel is just that - a .1 EFFECTS channel (120 Hz and down). In the home enviroment the .1 many times becomes the SUB channel (because the mains and surrounds are not full range) and placement of the sub then becomes much more critical than if it is just being used as the effects channel.

james

Adz523 · « **Reply #19 on:** 5 Aug 2004, 12:41 am »

I am being adivsed by Def Tech not to send a full range signal to my
BP7000sc's built-in subwoofers - as they'll try to play a full range signal which won't sound very good. So, instead it appears that what I am going to do is use a Y connector to run the unbalanced subwoofer signal out to the left and right LFE on the BP7000scs'. Then I am going to buy a passive subwoofer for the back of the room which will be connected with a single speaker cable to the unused amp channel in my 3 channel/5 channel Bryston set-up which will be connected through its balanced connection into the balanced subwoofer connection on the 1.7. All other audio connections will be made through the unbalanced inputs/outputs on the 1.7/amp(s).

Thoughts, comments, etc?