AVS Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
84 Posts
Discussion Starter · #1 ·
Hi.

I haven't found any definitive answers.

Is the 7125 bridgeable? I'd like to use two channels to power one speaker.
 

·
Registered
Joined
·
7,480 Posts

Quote:
Originally Posted by Ckindt  /t/1521813/outlaw-7125-bridgeable#post_24461432


Hi.

I haven't found any definitive answers.

Is the 7125 bridgeable? I'd like to use two channels to power one speaker.

Why? Are you aware that bridging causes the amp to see 1/2 the impedance of the speaker? What is the voltage swing and how much do you need?
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #4 ·

Quote:
Originally Posted by FMW  /t/1521813/outlaw-7125-bridgeable#post_24462679



Why? Are you aware that bridging causes the amp to see 1/2 the impedance of the speaker? What is the voltage swing and how much do you need?
 

I acquired a set of RTIA9s to replace my monitor 60s (front left and right) and I was considering existing options to provide the 9s with more headroom. 

 

Between my onkyo 929 and the outlaw I have plenty of channels to spare in my 11.1 setup so I can sacrifice 4 channels on the outlaw for two 9s.

 

I read a thread on the outlaw site that passively bi-amping is a possibility by splitting the rca input to the amp across two channels and connecting the two equal amp outputs to the speaker posts. In this case more available current should equal more headroom.? 

 

I'm not certain I'll necessarily need the headroom, but you never know.  I don't want to miss out on the 9s potential without buying another amp.

 

90% movies at -10db typical max volume
 

·
Registered
Joined
·
7,480 Posts

Quote:
I acquired a set of RTIA9s to replace my monitor 60s (front left and right) and I was considering existing options to provide the 9s with more headroom. 

It will simply make your 8 ohm speaker look like a 4 ohm speaker. While it will increase voltage swing it won't have much effect on power. So headroom would not be a reason to do it.
Quote:
Between my onkyo 929 and the outlaw I have plenty of channels to spare in my 11.1 setup so I can sacrifice 4 channels on the outlaw for two 9s[/quote}


If you don't need the amps, don't use them. I'm not aware of any AVR that provides for bridging. Bridging is something pro audio people use. It doesn't have much application in home audio.
Quote:
I read a thread on the outlaw site that passively bi-amping is a possibility by splitting the rca input to the amp across two channels and connecting the two equal amp outputs to the speaker posts. In this case more available current should equal more headroom.? 

Not really. It would simply split up the drivers and send full power to each rather than sending what each can dissipate. It accomplishes nothing. Proper biamplification is done by putting the crossover at line level in front of the amplifer, not in the speaker cabinets.
Quote:
I'm not certain I'll necessarily need the headroom, but you never know.  I don't want to miss out on the 9s potential without buying another amp.


90% movies at -10db typical max volume

I'm pretty sure you won't. Based on what you are saying I would doubt that you dissipate any more than 20 or 25 watts per channel on peaks. Any AVR that I know of will handle that without difficulty. Amplifier power, strangely, is one of the least important aspects of home audio.
 

·
Registered
Joined
·
12,990 Posts
Bridging an amplifier theoretically doubles the voltage, if the amp can still supply the current, and thus quadruples the power to the speaker (power goes as voltage squared). It does make the speaker "look like" half the impedance to the amplifier, which is why most amplifiers that do allow bridging, do not allow speakers as low in impedance as in their non-bridged mode. That is, a two-channel amp that will drive 4-ohm speakers as-is, will likely only rate the amp for 8-ohm loads when bridged. There are other issues with bridging amps, such as higher noise and stability.


I tend to agree with the rest of above, i.e. it is very unlikely you actually need to bridge the amp, even if you could.
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #7 ·

Thanks for the valuable insight.

 

I'll just leave everything as is and will likely be pleased.

 

This post in the outlaw saloon is misleading me.

They talk about leaving the jumper bars on the speakers and running two amp channels with the same signal split from the receiver.  Wouldn't this allow for more available current?
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #8 ·

Quote:
Originally Posted by FMW  /t/1521813/outlaw-7125-bridgeable#post_24463058


If you don't need the amps, don't use them..
I need at least two channels of the 7125, but use them all.  The 929 only has 9 amps and requires 2 external amps for the 11 channel output via pre-outs.

Currently I only run the FL,FR,BL and BR off the 929 so it can focus its power on the fronts mostly.
 

·
Banned
Joined
·
5,866 Posts
If your speakers are bi-ampable, you could use Y cable unless that causes a problem with shorting inputs or something like that. I used a two channel poweramp to bi-amp my center.
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #10 ·

Quote:
Originally Posted by fatbottom  /t/1521813/outlaw-7125-bridgeable#post_24465073


If your speakers are bi-ampable, you could use Y cable unless that causes a problem with shorting inputs or something like that. I used a two channel poweramp to bi-amp my center.
hmm..
  

This is not recommended for real results.  My speakers are bi-ampable, but this still leaves the internal crossovers in tact and you are supplying a full range signal to each post set.

 

I was inquiring about running two full range signals from two separate amp channels with the same source signal to both speaker input posts and leave the jumper bar jumped. 
 

·
Banned
Joined
·
5,866 Posts
If you use a av amp, then pre-outs are filtered are they not (set them to small 80hz for example) I don't know if you can use one of these- contact Outlaw

http://topzoneonline.com/rca-y-cable-1-rca-plug-to-2-rca-plugs-3-inch.html


My poweramps a have in/out type connection

http://att.jdbbs.com/forum/day_070304/20070304_d2c0580ec2ca40ec3afaFCiDjkqG1lZp.jpg


Take short cable from load left, to input right. Input left is the RCA cable from the pre-amp
Quote:
They talk about leaving the jumper bars on the speakers and running two amp channels with the same signal split from the receiver. Wouldn't this allow for more available current?

ummmm. No? BANG
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #12 ·

Quote:
Originally Posted by fatbottom  /t/1521813/outlaw-7125-bridgeable#post_24465207


If you use a av amp, then pre-outs are filtered are they not (set them to small 80hz for example) I don't know if you can use one of these- contact Outlaw

http://topzoneonline.com/rca-y-cable-1-rca-plug-to-2-rca-plugs-3-inch.html


My poweramps a have in/out type connection

http://att.jdbbs.com/forum/day_070304/20070304_d2c0580ec2ca40ec3afaFCiDjkqG1lZp.jpg


Take short cable from load left, to input right. Input left is the RCA cable from the pre-amp

ummmm. No? BANG
i don't understand your recommendation on the wiring.

 

I don't think the amp would go bang since there is no short circuit. With the jumpers left the load should be the same to both amp channels, but is there any benefit?
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #14 ·

·
Registered
Joined
·
3,297 Posts
You can bi-amp, but not bridge your amp. Big difference. Some car amps and some pro amps can bridge channels.

Very few home theater amps can bridge 2 channels into one. And going from 125 watts per channel to 200 isn't

going to change the performance of your speakers anyway.
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #16 ·

Quote:
Originally Posted by kikkenit2  /t/1521813/outlaw-7125-bridgeable#post_24465670


 And going from 125 watts per channel to 200 isn't

going to change the performance of your speakers anyway.
Yeah, i'm at that conclusion, but am just trying to sort out this bi-amping thing. Why so common if so useless?

 

Thanks everyone for being patient with my ignorance.
 

·
Registered
Joined
·
3,297 Posts

Quote:
Originally Posted by Ckindt  /t/1521813/outlaw-7125-bridgeable#post_24465717


Yeah, i'm at that conclusion, but am just trying to sort out this bi-amping thing. Why so common if so useless?
It is called marketing. Once one brand offered it and sales boomed, everybody else copied it so they wouldn't be left behind. Same thing with speakers. We see people all the time want speaker brand a instead of speaker brand b just because of dual binding posts with metal jumpers. A $5 part made some people rich. Polk even puts them on their cheap bookshelf speakers. Just don't let your jumpers come loose.
 

·
Registered
Joined
·
7,480 Posts

Quote:
Originally Posted by Ckindt  /t/1521813/outlaw-7125-bridgeable#post_24465717


Yeah, i'm at that conclusion, but am just trying to sort out this bi-amping thing. Why so common if so useless?


Thanks everyone for being patient with my ignorance.

The industry is good at catering to beliefs.
 

·
Registered
Joined
·
145 Posts
I have been Bi-Amping my front L&R Polk RT8 speakers for a few years now using an Onyko 805, 7.1 receiver. The 805's additional 2 channels can be used to Bi-Amp the Polks, as I use a 5.1 setup, and the resulting sound is noticeably more accurate & stable. It seems Bi-Amping can minimize or eliminate Intermodulation Distortion, (IM), between the crossovers in the speaker by providing power directly to the Bass/Midrange & Tweeters independently. It just sounds cleaner and maybe a bit sharper than not Bi-Amping. By the way Bi-Wiring is totally useless and produces no advantage in your audio system.
 
1 - 20 of 21 Posts
Top