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Does impedance of a speaker change when one bi-amps?

I'm fairly new to the audiophile arena and i have seen this question asked before, but not answered.
rickytickytwo
bdp24's avatar
bdp24
9,445 posts
 

The most interesting loudspeaker product I am aware of is Roger’s new Music Reference ESL loudspeaker/dedicated direct-drive OTL amplifier combination (a great idea, though audiophiles don’t like to have their amp dictated to them ;-). ESL transparency, speed, lack of coloration (unsurpassed vocal and instrumental timbre, texture, etc.), and all the other ESL attributes (okay, I love ESL’s!), and no input (step up) transformer. And driven by a dedicated, direct-drive OTL amp (no output transformer, the tubes connected right to the ESL panels). What could be more pure?! A powered sub is included, and since not a single other power amp or other electronic component is required or necessary, you just feed the system the signal of your choice. The combined price is less than that of the multi-driver/complex-crossover monstrosities reviewed in Stereophile every month. I’m saving up for my pair ;-) .

There are companies making powered monitor loudspeakers for the pro sector (Westlake Audio, for one), but if you have heard any of them you know they aren’t exactly audiophile products, made for listening to music in the home. Sensitive and dynamic yes, but too colored, shouty, and coarse for me.

steve59's avatar
steve59
1,645 posts
 
WOW, you guys complicated that conversation.

My Integrated amp rated at 250/8-425/4 shut down driving my power hungry speakers that have 2 pair of binding posts on back they’re 4 way 6 ohm rated and manufacturer recommends 500 watts. My question for the experts assuming I can get the amps output levels matched is, Would my integrated be less likely to overheat at the same spl if I added a 2nd amp, removing the strap to horizontally bi amp the speakers? also if I got output levels matched would amps of identical power be necessary or could I wire a pair of 350 mono's to the bass of each speaker and use the int to drive the top end?
erik_squires
15,703 posts
 
Would my integrated be less likely to overheat at the same spl if I added a 2nd amp, removing the strap to horizontally bi amp the speakers?


Yes. Passive bi-amping would limit the current for the bass to only one of the two amps, therefore reducing the actual power drawn during the same musical performance as before.

also if I got output levels matched would amps of identical power be necessary


No

or could I wire a pair of 350 mono’s to the bass of each speaker and use the int to drive the top end?


Sure. An added advantage of this method is the ability to add EQ to the bass section alone, often a good improvement.

Best,
E

erik_squires
15,703 posts
 
If you are going to go with active crossovers, you seriously should just make your own speaker. DIY  your own speaker pair is something I think every audiophile should do at least once.

Build it from the ground up and learn what you need to do along the way, instead of this half baked approach.

For the record, almost all passive crossovers also include some form of EQ. If you plan to remove and replace a passive crossover you need to be prepared to do both.
And now I leave you guys to hack and play around.

Best,
E
ramtubes's avatar
ramtubes
460 posts
 
@steve59 

WOW, you guys complicated that conversation.

My Integrated amp rated at 250/8-425/4 shut down driving my power hungry speakers that have 2 pair of binding posts on back they’re 4 way 6 ohm rated and manufacturer recommends 500 watts. My question for the experts assuming I can get the amps output levels matched is, Would my integrated be less likely to overheat at the same spl if I added a 2nd amp, removing the strap to horizontally bi amp the speakers? also if I got output levels matched would amps of identical power be necessary or could I wire a pair of 350 mono's to the bass of each speaker and use the int to drive the top end?


Sometimes getting technical gets to the answer far better than a stack of nontechnical thought.

 When I tried to run my  ESLs off a high quality integrated I learned a lot. For instance the rated power is only deliverable into a resistive load. Anything reactive shut the amp down and a message came up  "check for shorted speaker wires"  That speaks volumes. The amp thinks anything below X ohms is a short. 

After reading the manual carefully I found that we could selectd 4 or 8 ohms but that did not affect the output power at all, only where the protection cut in. Selecting 4 was worse than 8 and shut downn sooner. This is not the behavior of a good solid amplifier.

Integrateds are not rough and ready power amps in general. 250/425 watts is power amp land and I mean big power amp land. How much does your amp weigh? Would you care to tell us its model? 
Sounds like a simple case of amplifier does not like speaker. A second amp will help indeed. Let the current integrated take the lighter load. 

Have you found an impedace curve for the speaker. Usually you can just google its name + impedance curve using images.


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