bi-amping doubts - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 3rd November 2011, 05:03 AM   #11
Francec is offline Francec  Australia
Banned
 
Join Date: Jul 2006
Location: Port Melbourne, Australia
You won't need 100W amps for bi-amping unless you want to use it as a PA for a small hall. Passive speakers need more power because they waste energy in the crossover.
I use LM3886 (50W max for 88dB drivers) chip amps for all three drivers in an active three way (but bridged for for the woofer).

Might I also suggest proper grammar, capitalisation (no "z", I'm Australian and use "proper" English ) and punctuation out of respect for your fellow forum members?

Frank
  Reply With Quote
Old 3rd November 2011, 09:07 AM   #12
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
Here are a couple links to a bi-amp project I have been working on.

BPA300 Round 2
BPA300 Round 2
BPA300 Round 2

The BPA-150s will be driving PExpress 8Ē 4ohm speakers in a tuned bass reflex cabinet. The MyRefs push the tweeters. My approach is more from the listenerís side than that of an amp designer. The active crossover Iím using has both low/mid and mid/high adjustments as well as a low-sum mode for a subwoofer. Both of these amps have a proven ability to produce excellent sound and itís my contention/hope the adjustments provided by the crossover will provide the correct SPL from the multiple drivers.

Iím suspecting I might have to switch to something like the Behringer DCX2496 to obtain the signal shaping for the correct balances. In addition to all the calculations for the amps as mentioned above, each driver has its own peculiarities to deal with
.
The setup I have now is working well in test mode with el-cheapo drivers. I fried a couple tweeter voice coils that I believe was the result of oscillation triggered by a grounding issue, but that appears to be corrected. There is still a bit of hum (completely masked by the music) in the BPA section that has to be tracked down.

More to comeÖÖ..
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."
  Reply With Quote
Old 3rd November 2011, 09:27 AM   #13
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by Francec View Post
You won't need 100W amps for bi-amping ......................... chip amps for all three drivers in an active three way (but bridged for for the woofer).
I can't agree with that generalised statement.

How would you achieve 110dB peak SPL at the listening position, using stereo, not surround sound in any of it's forms?

You are confirming that active speaker set up has higher efficiency.
Please explain how bi-amping can have better efficiency than a standard amp & passive crossover speaker when the twin amps are still driving the speakers via their crossovers.
__________________
regards Andrew T.
  Reply With Quote
Old 3rd November 2011, 01:00 PM   #14
diyAudio Member
 
Join Date: Jan 2011
hi all
i read (again and again) the bi-amping article in the following link
BiAmp (Bi-Amplification - Not Quite Magic, But Close) - Part 1

as per the explaination (as far as my understanding goes), if xover point for 2way is 3khz, then only 15% of power goes to tweeter. that means in case of biamping if i am using 100w for woofers/mids then only 15w is needed to driver tweeters.
  Reply With Quote
Old 3rd November 2011, 01:56 PM   #15
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: Near Vancouver
soundnovice, here is a real world example:

I have a number of amps available to me and I have always used a LF amp that is between 2X and 4X that of the HF amp. The XO's range from 650Hz to about 2.5KHz, all active, never an imbalance or an overdrive. And yes, the tweeter has always been more efficient the the LF driver. That's pretty standard with PA gear and rather the norm with HiFi stuff.
__________________
Next stop: Margaritaville
Some of Cal's stuff | Cal Weldon Consulting
  Reply With Quote
Old 3rd November 2011, 02:45 PM   #16
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by Cal Weldon View Post
I have always used a LF amp that is between 2X and 4X that of the HF amp. The XO's range from 650Hz to about 2.5KHz, all active, never an imbalance or an overdrive. And yes, the tweeter has always been more efficient the the LF driver. .
I absolutely agree.

Can I use this "real world example" to illustrate the point.

take a 90dB bass driver and a 96dB treble driver and cross them over to provide a full range speaker.

Add a four times power capable amp to the bass driver and a single power capable amp to the treble driver.
Result: the same peak SPL from both drivers.

Corollary:
take two or more drivers with the same impedance and the same sensitivity and supply them from equal power capability amplifiers and you get the same peak SPL, provided that both drivers can convert that electrical energy into useful sound energy.
__________________
regards Andrew T.
  Reply With Quote
Old 3rd November 2011, 05:18 PM   #17
diyAudio Member
 
Join Date: Nov 2011
Location: Santa Barbara, CA
Quote:
Originally Posted by AndrewT View Post

Add a four times power capable amp to the bass driver and a single power capable amp to the treble driver.
Result: the same peak SPL from both drivers.
This is true iff the drivers have the same impedance.
  Reply With Quote
Old 4th November 2011, 05:14 AM   #18
diyAudio Member
 
Join Date: Jan 2011
controlling SPL is not an issue if u see the active xover ckt given in Rod Elliot's project page Linkwitz-Riley Electronic Crossover

copyright question: if i plan to design my own PCBs for personal use do I have to take permission from Rod Elliott?
  Reply With Quote
Old 4th November 2011, 06:27 AM   #19
cbdb is offline cbdb  Canada
diyAudio Member
 
Join Date: Oct 2008
Location: Vancouver
Quote:
take a 90dB bass driver and a 96dB treble driver and cross them over to provide a full range speaker.

Add a four times power capable amp to the bass driver and a single power capable amp to the treble driver.
Result: the same peak SPL from both drivers.
Even if the drivers are the same efficiencies, you would need more power in the woofer. Most music has most of its power in the low end. (Fletcher-Munsen)
  Reply With Quote
Old 4th November 2011, 07:06 AM   #20
diyAudio Member
 
Join Date: Dec 2005
Location: Kuala Lumpur
Music may have more average power at low frequencies, but my own measurements show that many over compressed CDs have digital full scale swing when high passed at 2kHz with 3rd order cutoff. To avoid clipping the HF amplifier needs as much headroom as the LF although the peak to average ratio will be fairly high

It can be argued that clipping the active speaker HF amplifier does not sound too bad and clearly does not have the side effect of increasing HF power that a clipped full range amplifier can
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Bi-amping diyman Multi-Way 14 31st August 2012 12:24 AM
New to bi-amping sonicman Solid State 11 2nd October 2008 12:24 PM
Bi-amping keyser Multi-Way 2 10th February 2005 11:57 AM
bi amping felipe_diy Chip Amps 6 24th September 2003 02:05 AM
Bi amping help. CryingDragon Parts 2 25th September 2002 08:17 PM


New To Site? Need Help?

All times are GMT. The time now is 07:48 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2