Speakers and Sub Off Same Amp Terminals? - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 14 Old 06-03-2012, 02:44 PM - Thread Starter
AVS Special Member
 
John Robert's Avatar
 
Join Date: Sep 2003
Location: Las Vegas
Posts: 3,526
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I've got these 4 ohm Adam speakers in my 2-channel set up:

http://www.adam-audio.com/en/install...77/description

Powered by this Anthem amp:

http://www.anthemav.com/products/ant...integrated-225

I want to add a sub but the amp has only one set of speaker terminals and no sub or preamp out. Can I use spades and bananas to run speaker level connection to both my Velodyne sub and the speakers off the one set of speaker terminals? My obvious concern would be the load presented to the amp. Thanks in advance...

John

"What happens in Vegas..."
John Robert is offline  
Sponsored Links
Advertisement
 
post #2 of 14 Old 06-04-2012, 04:25 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,279
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 674 Post(s)
Liked: 1142
Quote:
Originally Posted by John Robert View Post

I've got these 4 ohm Adam speakers in my 2-channel set up:

http://www.adam-audio.com/en/install...77/description

Powered by this Anthem amp:

http://www.anthemav.com/products/ant...integrated-225

I want to add a sub but the amp has only one set of speaker terminals and no sub or preamp out. Can I use spades and bananas to run speaker level connection to both my Velodyne sub and the speakers off the one set of speaker terminals? My obvious concern would be the load presented to the amp. Thanks in advance...

You didn't say which Velodyne subwoofer you want to use, so I picked one fror you. Here's its manual:

http://velodyne.com/pdf/cht/cht-q_manual_revc.pdf

Turn to Figure 5 on page 11. Basically they want you to hook speaker wires from your amplifier to the speaker input terminals on the subwoofer, and connect your existing pair of speakers to the speaker output terminals on the subwoofer.

This is done for both your convenience and also for performance reasons. The convenience is that you now have places to attach all of your gozintas and comezoutas. ;-)

The technical reason is described on page 17. The subwoofer has a built-in crossover that protects your existing speakers from loud bass signals that are now being handled by your subwoofer. Routing the speaker wiring through your subwoofer accomplishes that for you.
arnyk is offline  
post #3 of 14 Old 06-04-2012, 08:22 AM
AVS Addicted Member
 
cel4145's Avatar
 
Join Date: Mar 2009
Location: Grand Rapids, MI
Posts: 11,645
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 212 Post(s)
Liked: 746
That sub would not be my choice for your speakers in a 2 channel setup. Your Adam GTC77s have large 7" woofers with a frequency response down to 38hz. That Velodyne sub has a single high pass crossover frequency of 120hz, which means you'll be passing off almost all the midbass range to the sub when you don't need to. Moreover, crossing over the sub at that high a frequency may cause it to be localizable, as well as losing some of the stereo midbass effects you may be getting with some music.

Besides, if you live in the US, you probably won't be able to find that sub under that model # anyway; it's a non-US market designation, and I think the US market model is the DEQ.

Assuming your room isn't very large (room size affects sub performance), I'd look at the SVS PB12-NSD which has a high pass filter at 80hz. The SVS subs are considered excellent values at their price point (better than most Velodynes). Although an even lower crossover could be better; it's just hard to find a sub with that capability at a good price.

Your questions are answered: Speaker FAQ
HT: Energy RC-50, RC-LCR, Veritas VS Surrounds | Dual CHT SS 18.1s | Denon AVR-888 | modified Dayton SA1000 | Antimode 8033C
Desktop: CBM-170 SE | SVS SB-1000 | Audio-GD NFB-11 | HK 3390
Headphone & Portable HE-400 | K612 Pro | HP150 | DX50 | E12
cel4145 is offline  
post #4 of 14 Old 06-04-2012, 08:55 AM
Senior Member
 
Theonetruegreg's Avatar
 
Join Date: Mar 2010
Location: Westminster, CO
Posts: 215
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 35
Should be able to use a second pair of speaker cables running off to sub's line level inputs, and setting the LPF on the sub to >40hz


TV's ain't theaters buddy.

My junk collection.

Theonetruegreg is offline  
post #5 of 14 Old 06-04-2012, 09:25 AM - Thread Starter
AVS Special Member
 
John Robert's Avatar
 
Join Date: Sep 2003
Location: Las Vegas
Posts: 3,526
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by arnyk View Post

You didn't say which Velodyne subwoofer you want to use, so I picked one fror you. Here's its manual:

http://velodyne.com/pdf/cht/cht-q_manual_revc.pdf

Turn to Figure 5 on page 11. Basically they want you to hook speaker wires from your amplifier to the speaker input terminals on the subwoofer, and connect your existing pair of speakers to the speaker output terminals on the subwoofer.

This is done for both your convenience and also for performance reasons. The convenience is that you now have places to attach all of your gozintas and comezoutas. ;-)

The technical reason is described on page 17. The subwoofer has a built-in crossover that protects your existing speakers from loud bass signals that are now being handled by your subwoofer. Routing the speaker wiring through your subwoofer accomplishes that for you.

Sorry, should have been more specific on the sub. It's an older DD12 (not 12+) and has speaker input terminals but not output terminals, picture attached...

John
LL

"What happens in Vegas..."
John Robert is offline  
post #6 of 14 Old 06-04-2012, 09:28 AM - Thread Starter
AVS Special Member
 
John Robert's Avatar
 
Join Date: Sep 2003
Location: Las Vegas
Posts: 3,526
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by cel4145 View Post

That sub would not be my choice for your speakers in a 2 channel setup. Your Adam GTC77s have large 7" woofers with a frequency response down to 38hz. That Velodyne sub has a single high pass crossover frequency of 120hz, which means you'll be passing off almost all the midbass range to the sub when you don't need to. Moreover, crossing over the sub at that high a frequency may cause it to be localizable, as well as losing some of the stereo midbass effects you may be getting with some music.

Besides, if you live in the US, you probably won't be able to find that sub under that model # anyway; it's a non-US market designation, and I think the US market model is the DEQ.

Assuming your room isn't very large (room size affects sub performance), I'd look at the SVS PB12-NSD which has a high pass filter at 80hz. The SVS subs are considered excellent values at their price point (better than most Velodynes). Although an even lower crossover could be better; it's just hard to find a sub with that capability at a good price.

Thanks. I already have a sub, hoping to figure a work around to use it. Just bought the speakers so no new sub in my immediate future ...

John

"What happens in Vegas..."
John Robert is offline  
post #7 of 14 Old 06-04-2012, 09:32 AM - Thread Starter
AVS Special Member
 
John Robert's Avatar
 
Join Date: Sep 2003
Location: Las Vegas
Posts: 3,526
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Theonetruegreg View Post

Should be able to use a second pair of speaker cables running off to sub's line level inputs, and setting the LPF on the sub to >40hz


That's what I was proposing to do - with 4 ohm speakers that's not too demanding a load for the amp? I guess I could try it and see if any protection circuits trip. Thanks to all for their feedback...

John

"What happens in Vegas..."
John Robert is offline  
post #8 of 14 Old 06-04-2012, 09:50 AM
AVS Special Member
 
SAM64's Avatar
 
Join Date: Apr 2011
Posts: 1,580
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 69
Quote:


with 4 ohm speakers that's not too demanding a load for the amp?

The sub has a power amp in it, the 'speaker' inputs present a high impedance load.
Nothing to worry about.
SAM64 is offline  
post #9 of 14 Old 06-04-2012, 10:08 AM - Thread Starter
AVS Special Member
 
John Robert's Avatar
 
Join Date: Sep 2003
Location: Las Vegas
Posts: 3,526
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by SAM64 View Post

The sub has a power amp in it, the 'speaker' inputs present a high impedance load.
Nothing to worry about.

Thanks for the clarification. I had figured as much but nice to have the confirmation...

John

"What happens in Vegas..."
John Robert is offline  
post #10 of 14 Old 06-08-2012, 04:48 PM
AVS Special Member
 
4DHD's Avatar
 
Join Date: Aug 2004
Location: sierra ecuadoriana
Posts: 5,811
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 62
Long before MC/HT, all subs were connected via speaker outputs from the amp. And as mentioned, the impedance load to the sub is nothing to worry about.
You either run parallel wires off the amp, one to speaker, one to sub. Or run wire to speaker, then onto the sub. Third; run wires to sub, then onto speakers.
4DHD is offline  
post #11 of 14 Old 06-11-2013, 05:27 PM
Senior Member
 
nx211's Avatar
 
Join Date: Aug 2004
Location: New York
Posts: 297
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 17
Quote:
Originally Posted by 4DHD View Post

Long before MC/HT, all subs were connected via speaker outputs from the amp. And as mentioned, the impedance load to the sub is nothing to worry about.
You either run parallel wires off the amp, one to speaker, one to sub. Or run wire to speaker, then onto the sub. Third; run wires to sub, then onto speakers.

Sure, the sub amp is fine, but what about the load placed on the main channel amps with each channel now bi-wired? (Parallel example). Main channel amp impedance is a sensitive thing you know. Also, you loose the ability to off-load some/most of the bass frequencies from the main speakers into the sub with every option except option 3. (Presuming that the sub has variable crossover ability).


nx211
nx211 is offline  
post #12 of 14 Old 06-12-2013, 05:44 AM
AVS Special Member
 
4DHD's Avatar
 
Join Date: Aug 2004
Location: sierra ecuadoriana
Posts: 5,811
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 62
The original sat/sub back in the mid '70s connected just like that, parallel from the amp or the sub connected from the L/R speakers binding posts. But the result was the same, still parallel wiring.
4DHD is offline  
post #13 of 14 Old 06-12-2013, 07:43 AM
Member
 
Wayne Highwood's Avatar
 
Join Date: Jun 2012
Posts: 165
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 35
Quote:
Originally Posted by nx211 View Post

Sure, the sub amp is fine, but what about the load placed on the main channel amps with each channel now bi-wired? (Parallel example). Main channel amp impedance is a sensitive thing you know. Also, you loose the ability to off-load some/most of the bass frequencies from the main speakers into the sub with every option except option 3. (Presuming that the sub has variable crossover ability).


nx211

Your main amp will be fine. The sub's high input impedance makes it almost invisible to your main amp. And you're correct, without a high pass for the mains you do forego a bit of dynamic range, and get a bit more modulation type distortion, but not much if you listen at sane levels. Consider proper bass management if you want to blast it.

[edit...it's like I don't even read...Sam and 4D already covered this, so sorry for the retread. But reflecting on your rig and it's similarities to one of mine, I think your Adams will do well enough full range for you not to have issues, unless you listen at triple digit spls regularly, in which case you would benefit from upstream bass management. Enjoy the music.]
Wayne Highwood is offline  
post #14 of 14 Old 06-12-2013, 09:42 AM
AVS Special Member
 
Will2007's Avatar
 
Join Date: Sep 2007
Posts: 1,925
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 140
Good question, OP. Thanks for asking it. Also, mucho thanks for those who responded. Your information is greatly appreciated not only by the OP, but also by at least this lurker of the thread (who de-lurked to respond).
Will2007 is offline  
Reply 2 Channel Audio

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off