Can one connect 2 subwoofers to a receiver that only has a single sub output?

[Alexandre]

Hi there,

I currently have a JL Audio Fathom 110 connected to a Classé Sigma SSP preamp and I was wondering what my best option for adding a second sub would be. Generally should the 2 subs be identical? If I go with a second fathom, I can actually connect them together which is nice but what if I don't go with a Fathom. Could I potentially plug 2 subs, somehow, in the pre-amp?

Thanks!
Alex.

 

[j_garcia]

Yes, ideally the second one should be identical. To connect two all you need is a Y spliter, nothing more.

 

[Alexandre]

Yes, ideally the second one should be identical. To connect two all you need is a Y spliter, nothing more.

Cool, I sort of had assumed that'd be the case but was wondering if there would be some power issues splitting the signal (realizing that this is a line level signal, not a heavily amplified signal, but still).

A neat feature of the fathom is that they can actually serially drive up to something like 10 subs… if I find myself swimming in a pile of cash I'll report on how that works out.

 

[WaynePflughaupt]

Yes, you want matching subs. If not, overall performance will be “dumbed down” to that of the lesser sub. You can find a case study with graphs here.

Regards,
Wayne A. Pflughaupt

 

[Auditor55]

Yes, you want matching subs. If not, overall performance will be “dumbed down” to that of the lesser sub. You can find a case study with graphs here.

Regards,
Wayne A. Pflughaupt

I keep reading that, overall performance will be “dumbed down”. Please substantiate that claim.

 

[WaynePflughaupt]

Did you review the information and graphs linked in the post you quoted?

Regards,
Wayne A. Pflughaupt

 

[Auditor55]

Did you review the information and graphs linked in the post you quoted?

Regards,
Wayne A. Pflughaupt

I looked at the graphs. Having said that, my impression is that those are the result he was getting. Someone more skilled at what he was trying to do might get better results, do you agree?

 

[WaynePflughaupt]

Read the text, it explains the graphs. It’s audio physics, not skill, so I’d say no.

Regards,
Wayne A. Pflughaupt

 

[PENG]

I don't think it always get dumbed down. There are just too many variables for this to be universally true. Case in point, Audyssey XT32 and Sub EQ HT was able to integrate my PCU and PB13U very nicely. No dumb down in my set up.

 

[Auditor55]

Read the text, it explains the graphs. It’s audio physics, not skill, so I’d say no.

Regards,
Wayne A. Pflughaupt

Maybe I should have used the word "experienced" instead of skill in questioning the poster's ability to get his LF is his room more even through sub placement. I read some the text under the graph's, however it doesn't show why the lesser subs are dragging down the greater subs.

 

[PENG]

Again, it depends, my two different subs work very well together though I did not dial them in manually. Some people prefer to set their full range mains to large and select LFE+Main so they effectively have different subs, the other subs being the mains. They wouldn't being doing that if you felt their sub(s) got dumbed down by their mains.

 

[WaynePflughaupt]

It’s not so much an issue of different subs as it is mismatched subs. For instance, trying to integrate (as an extreme example) an 8-incher with a 75-watt amp only good down to ~40 Hz and a 500-watt, 15-incher that digs down to 16 Hz.

Regards,
Wayne A. Pflughaupt

 

[PENG]

It’s not so much an issue of different subs as it is mismatched subs. For instance, trying to integrate (as an extreme example) an 8-incher with a 75-watt amp only good down to ~40 Hz and a 500-watt, 15-incher that digs down to 16 Hz.

Regards,
Wayne A. Pflughaupt

Okay that's a little different, thanks for the clarification.

 

[WaynePflughaupt]

I read some the text under the graph's, however it doesn't show why the lesser subs are dragging down the greater subs.

Sure it does. Allow me to help: The OP to the thread had two subs that had extension to 20 Hz and two that had extension to 30 Hz. So...

So – what happens when we combine the two? The results are predictable: We have four subs operating 30 Hz and above, so the total system (all subs operating) has good extension down to only 30 Hz. Below that point response falls, since only two subs are operating below 30 Hz.

Then there’s the other issue:

The other issue with mismatched subs is that the “weaker” one will max-out and start distorting, bottom out, etc. before the more capable one does. Well, you can’t push the system any harder than the point where the weaker sub gives up, unless you want to destroy it. Thus, maximum system output (SPL) is also limited by the lesser sub; the more powerful sub never gets a chance to live up to its potential.

Make sense?

Regards,
Wayne A. Pflughaupt

 

[Auditor55]

Sure it does. Allow me to help: The OP to the thread had two subs that had extension to 20 Hz and two that had extension to 30 Hz. So...




Then there’s the other issue:



Make sense?

Regards,
Wayne A. Pflughaupt

The OP's 30 Hz capable subs blocked his 20 Hz capable subs from from extending to 20 Hz when played all together? In reading his post I kept trying to figure out what he was trying to do, was he trying to get his response flat down to 20 HZ.

 

[WaynePflughaupt]

No, nothing is "blocked" below 20 Hz. "Overwhelmed" might be a better way to put it. When you have four subs generating from say, 90 Hz to 30 Hz, but only two are generating below 30 Hz, it should be obvious that the latter pair can’t by themselves generate the same output below 30 Hz as all four were above 30 Hz. So obviously when you combine all four, response is good down to 30 Hz but then drops below that point (which is what the graphs show).

Perhaps a visual will help.

90 Hz---------------------------------------30 Hz
90 Hz---------------------------------------30 Hz
90 Hz-----------------------------------------------------------20 Hz
90 Hz-----------------------------------------------------------20 Hz

Make sense?

Regards,
Wayne A. Pflughaupt