Home Theater Forum and Systems banner

1 - 20 of 23 Posts

·
Registered
Joined
·
58 Posts
Discussion Starter #1 (Edited)
Dual mono subs => splitting and design questions

I'll be making two seperate subs.

They will be connected:

Receiver (sub out) -> behringer dsp1124 -> stereo PA amp -> subwoofers

now is my question, where and how do I split the channel?

My thoughts were RCA (receiver) -> 2x XLR (thus using the two channels of the behringer, but probably linked) and from that point on using xlr-xlr.

Is that the best way, or should I split after the behringer?

Thanks for the advice.

Wouter
 

·
Premium Member
Joined
·
1,941 Posts
My thoughts were RCA (receiver) -> 2x XLR (thus using the two channels of the behringer, but probably linked) and from that point on using xlr-xlr.
I think that'sthe best way. I split the signal at the output of the receiver using RCA to dual 1/4" mono jack fed to the FBQ 2496
Is that the best way, or should I split after the behringer?
After the behringer will not allow for induvidual control of your subs, which is may not be acceptable depending on your setup.
 

·
Registered
Joined
·
56 Posts
daxie, those separate subs you're configuring aren't stereo, they're dual-mono.

I have 2 SWs...



...that are both stereo and dual-mono. I feed the (mono, of course) LFE signal (the blue cable) to one input of an inexpensive Behringer mixer...



...and the stereo-bass outputs of a 3-way crossover, a dbx DriveRackPA, into a different stereo input pair of the mixer. The mixer allows me to change the relative and absolute levels of the 2 inputs quite easily.

Splitting your mono signal as has been recommended makes sense to me.
 

·
Registered
Joined
·
241 Posts
What amp are you useing? Some new amps have three modes, stereo/bridged/and Parallel. If your amp has parallel mode then the amp splits the #1 input to both chanels, so you still have independant level control of each chanel, but saves having a splitter and running two cables from the reciever all the way to the amp. If it dosn't then it dosn't realy matter were you spit the signal, after or before the behringer shouldn't make any difference, do whatever is easiest for getting and running cables.
 

·
Premium Member
Joined
·
1,941 Posts
If it dosn't then it dosn't realy matter were you spit the signal, after or before the behringer shouldn't make any difference
How do you eq. each sub if you split after BFD?
 

·
Registered
Joined
·
241 Posts
Is there a reason to eq each sub differently? besides he said he would run the behringer with the chanels linked anyway.
 

·
Premium Member
Joined
·
1,941 Posts
Is there a reason to eq each sub differently? besides he said he would run the behringer with the chanels linked anyway.
Sure! If the room is not shoe box shaped and if subs are not symmetrical in room vis-à-vis of listening position, it might even become a must to equalize them differently.

He mentioned he would probably link the chanels ... that I strongly vote against since it is hard to require more than 12 or 20 filters/chanel (depending on model) unless he would be doing something wrong, not to mention loss of individual control over the subs (if needed for any reason).

Anyway I was answering his question and giving ideas about plausible result of each connection method. Choice is up to him now :)
 

·
Registered
Joined
·
58 Posts
Discussion Starter #8
maybe some info about the room.

It's a 6x4 (metres) attic room, under the roof.

This means it is not a shoe box, but it is a perfect symmetrical thing. Subs will be place left and right next to the listening position. So in fact I expect to need the equalising only mildly (I rather go with some unevenness in the respons than using a lot of equalising). Since the positioning is symmetrical, I also expect to just use same eq on both subs. However, I do not consider that a requisite, I know that linking might not be the best option.

amp will probably be a single ta-2400 to start with. And maybe add a second later when needed.
 

·
Premium Member
Joined
·
1,941 Posts
Daxie,

Sounds good! The TA amp is a good amp (slightly better that the EP 2500). What subs do you have?
 

·
Registered
Joined
·
58 Posts
Discussion Starter #10
Daxie,

Sounds good! The TA amp is a good amp (slightly better that the EP 2500). What subs do you have?
as in the other topic (where you responded, lol), I'll be building two subs on a CSS-SDX 15. Either sealed or LLT.

Being a small room, I'll probably go for a sealed design. IS there any way to know what room gain I would get?
 

·
Premium Member
Joined
·
1,941 Posts
Sorry Daxie,

I am so heavily loaded at work, as well as participating in so many threads I am glad I still remember my name :whew:

How big is your room? I hope I haven't already asked that question :dumbcrazy:
 

·
Registered
Joined
·
58 Posts
Discussion Starter #12 (Edited)
Sorry Daxie,

I am so heavily loaded at work, as well as participating in so many threads I am glad I still remember my name :whew:

How big is your room? I hope I haven't already asked that question :dumbcrazy:
you can find it 3 replies above yours :heehee:

6x4metres under the roof. the straight part of the walls is about 1 metre.
 

·
Premium Member
Joined
·
1,941 Posts
Yeah Daxie! That's what I was thinking. I was under the impression I saw it somewhere :nerd:

OK...Back to topic. It really depends on your listening habbits, but it seems that we are quite different. I have dual 18" LLT in a 3.8 * 5 m room, so I wouldn't do dual sealed subs in your room (but that's just me).
 

·
Registered
Joined
·
58 Posts
Discussion Starter #14
Yeah Daxie! That's what I was thinking. I was under the impression I saw it somewhere :nerd:

OK...Back to topic. It really depends on your listening habbits, but it seems that we are quite different. I have dual 18" LLT in a 3.8 * 5 m room, so I wouldn't do dual sealed subs in your room (but that's just me).
how much do you have to equalise? cause in my 4x3.8 room with my pb12+ I already have to do a -12dB at the lowest frequencies.

I just like to have a decent response without the need to equalise too much.

No use to have it extend further if you have to equalise it anyways afterwards, is there?
 

·
Premium Member
Joined
·
1,941 Posts
how much do you have to equalise? cause in my 4x3.8 room with my pb12+ I already have to do a -12dB at the lowest frequencies.
I am afraid you're talking about room mode. What freq. is it?
 

·
Registered
Joined
·
58 Posts
Discussion Starter #16 (Edited)
I am afraid you're talking about room mode. What freq. is it?
between 16-22Hz I have a large bump. But that's my current room.

I would have to know what to do in my new room :dumbcrazy:
Either go with two times LLT tuned to 13-15Hz or go sealed.

With sealed I don't know if I'll have the extension I want (maybe put in a linkwitz to extend it a bit?), and with LLT I don't know if it won't be too much room gain
 

·
Premium Member
Joined
·
1,941 Posts
between 16-22Hz I have a large bump. But that's my current room.

I would have to know what to do in my new room :dumbcrazy:
Either go with two times LLT tuned to 13-15Hz or go sealed.

With sealed I don't know if I'll have the extension I want (maybe put in a linkwitz to extend it a bit?), and with LLT I don't know if it won't be too much room gain
IMO Room gain is generally welcome below 25 Hz. I could never complain of a bump in the 16-22 Hz region :R as far as I watch movies !! :hsd:. Anyway, this is still reachable by a BFD (do you have one?).

A linkwitz transform will work at the expense of headroom (I don't like that much) as opposed to a bigger, more efficient box!

You are having a 6 * 4 meter room and 2 15" subs. If you're afraid of room gain :)heehee:) tune low.
Look at my equalized FR (my room is smaller, and subs are even bigger!). Just would like to point out no eq. is done below room mode (35 Hz) :)
 

Attachments

·
Registered
Joined
·
58 Posts
Discussion Starter #18 (Edited)
yep, I have one...

It appears I might go for llt after all. Same group delay as closed up until 30Hz, reaching 17ms at 20HZ is acceptable from an sq point of view.

Now see how big I can go... Bigger is better, right :p What would the minimum mounting depth of the css-sdx15 be?

It's depth from baffle to end of magnet is 224mm
 

·
Premium Member
Joined
·
1,941 Posts
Again...I don't mind Group delay at very LF 20 hz and lower... It gives the impression of a huge scary thing :1eye:

Are you that much limited with depth? 22.5 cm isn't that deep! Check how deep you can do and tell.
 

·
Registered
Joined
·
58 Posts
Discussion Starter #20
The driver is 22,5 deep. In-cabinet I have 37,5 depth...

(cabinet of 2x27mm plywood with a 21mm baffle, amounting to 45cm).

Best place to put dual subs is left and right from the listening position I have been told, thus this is my startof point.

the room is 4m wide. A bench of about 2,25 meters. Leaves me 1,75m.
Two subs of 45cm depth is 90 cm. Leaves me 0,85m or 40cm at both sides to walk by.

That's why I'm limited in depth.
 
1 - 20 of 23 Posts
Top