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jwilliam
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Amp Power to Speaker Needs

Can anyone provide an explanation on how to go about pairing an integrated amp and speakers so that the speakers will die before the amp (ie. - the volume can be continually increased WITHOUT meaningful distortion resulting, before the speakers fail)? This would probably involve the study of the "Measurements" portion of a Stereophile review, but what would be the important criteria to look for? I know there has to be more to it than just simply comparing the amp's watts-per-channel, the speakers' impedance, or the speaker manufacturer's maximum recommended watts to the speaker. I would also prefer to not buy any more watts/power than is needed to efficiently and cleanly drive the speakers to their limits. Any guidelines or suggestions you are aware of to accomplish this would be appreciated.

Jan Vigne
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Re: Amp Power to Speaker Needs


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Can anyone provide an explanation on how to go about pairing an integrated amp and speakers so that the speakers will die before the amp (ie. - the volume can be continually increased WITHOUT meaningful distortion resulting, before the speakers fail)?

Go to Radio Shack and buy some cheap headphones. Rip them apart and use the drivers as your main speakers by connecting them to the speaker outputs of your amplifier. If you have tone controls, turn the bass up to full and engage the loudness contour. Sit across the room and turn the volume on the amplifier up until the sound stops. The amplifier will probably have already started to clip. Clipping distortion is what kills most speakers.

Why do you wish to have your speakers die?

Elk
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Re: Amp Power to Speaker Needs

While too much power injudiciously applied can kill a speaker, the bigger problem is not having enough power to properly drive a power hungry speaker. Driving an amp too hard leads to clipping that can damage speakers, especially tweeters.

I'm with Jan, what exactly are you going for and why?

jwilliam
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Re: Amp Power to Speaker Needs

Sorry for my poor description of my information needs. I am chomping at the bit to buy a new system (integrated amp, player, and speakers) from scratch. I have narrowed down my choices for each, but am having a hard time deciding what amp to purchase, especially since they are rated quite differently in power (61 WPS at the low end, 150 at the high). Since all three have their pros/cons, I am trying to take into account the power they have available to drive the speakers, and to do so at high levels at times without resulting in your described result of distortion, strain to the amp, etc. So I would rather the amp have plenty of power to drive the speakers to higher levels without clipping/distortion, and only have to be concerned with blowing fuses on the speakers (I really don't want the speakers to die, just me using too strong of a descriptor). The components I am choosing between are listed on the "Please Cast Your Votes" thread on the Entry Level forum. If I can elaborate any better, please let me know what additional input would be helpful to you. Thanks for your responses, and your patience with a neophyte.

Elk
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Re: Amp Power to Speaker Needs

Got it!

At a minimum of 61 watts per channel you will have enough to play any reasonably efficient speakers quite loud in an average room. I don't recall the speakers you are looking at in your other thread, but I bet you will be fine with any of them.

The only caveat is that you will not get realistic rock concert levels without more power and large speakers, but I doubt you were expecting this anyway.

Elk
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Re: Amp Power to Speaker Needs

I just went to look at your other thread. I second the recommendation for the Revel Concerta F12 speakers. I really like Revel speakers overall and the F12's are amazing for the money. At 90dB efficiency they will get *loud* with 60 watts.

Great choices on all of your equipment lists, by the way. I can see being happy for a long time with any of them. Nice job!

Jan Vigne
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Re: Amp Power to Speaker Needs

.

Working into an 8 Ohm load resistor the voltage difference between a 60 and a 150 watt amplifier won't be what determines whether the amplifier will drive the speaker adequately at higher levels. I would be far more concerend with the ability of the amplifier to drive whichever speaker you choose at reasonable volume levels. After you've chosen the speaker decide which amplifier you'll need to adequately supply the actual power the speaker requires. Depending on the speaker this may require more current than another speaker choice might. Even then, you don't have enough information to really decide which amplifier to buy just by looking at on paper numbers.

If you are after high volume levels, you will find it easier to start with the most sensitive and highest efficiency speaker. The higher those two specs go, the less wattage you'll need. By choosing a speaker with 3-4dB higher sensitivity the 60 watt amplifier will likely play noticeably louder than the 150 watt amplifier with a less efficient speaker.

If you're not sure how to correlate specs, I would hope you are working with a good dealer who can translate your wishes into a decent system the first time out.

jwilliam
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Re: Amp Power to Speaker Needs

Much thanks, Elk and Jan. I will have to figure out how to audition the Revels, since the nearest dealer for them is 3 to 4 hours away (Houston, Dallas). Jan, your first paragraph expresses very well (compared to my fumbling attempts) the reason why I spun this thread - to ask how does one correctly match amp power/wattage with the expected speaker load. It doesn't appear to be an easy process, so if I don't make the long road trip, I might call the dealer and ask for suggestions/recommendations for amps/power requirements/etc. for the F12s. Thank you both very much for assisting me in my pursuit of a system that I will enjoy, and not have buyer's remorse for down the road. Good listen' to you both.

Jan Vigne
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Re: Amp Power to Speaker Needs

This topic has been covered in several threads. If you'll look through some of the recent archives, you'll find more information.

For now; http://www.symphonysound.com/articles/tubefriendly.html

For more place "tube friendly speakers" in a search engine. If a speaker is "tube friendly", it will be amplifier friendly. If you don't understand what you're reading here, I would once again encourage you to find a good dealer.

cyclebrain
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Re: Amp Power to Speaker Needs


Quote:
While too much power injudiciously applied can kill a speaker, the bigger problem is not having enough power to properly drive a power hungry speaker. Driving an amp too hard leads to clipping that can damage speakers, especially tweeters.


A bit off topic, but despite our universal belief about the damage to HF drivers caused by HF harmonics cuased by clipping is this really true? As the frequency to the speaker increases so does the impedance value of the crossover and the HF driver voice coil. This increase in impedance at higher frequencies cuases a decrease in current to the HF driver. Does one offset the other?

Jan Vigne
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Re: Amp Power to Speaker Needs

Nope! 'twas heat that killed the beast.

cyclebrain
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Re: Amp Power to Speaker Needs


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Nope! 'twas heat that killed the beast.

Damn, not another global warming fanatic.

Ergonaut
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Re: Amp Power to Speaker Needs

Another fine shot straight at the target...excellent

Boy have we done a massive amount of work in this area in the world of Power PA.

Jan holed in one here -- when an amplifier is clipping the PD across the coil holds a lot of DC content - Under this condition the coil heats up and cannot cool down until the clipping has ceased.

This is how underpowered amplifiers can destroy higher value Bass drivers in a PA stack. I use Large Concert PA as an example because I dont know of many instances when a Hi-fi enthusiast would run his amplifiers continuously to the limit as they do in open air concert.

This is something we used to simulate under bench conditions often to see how Eminence - JBL - Peavey - Martin - Electrovoice and other big Concert names coped with a thorough and comprehensive thrashing.

This was back in the early 80's when the first vented airgaps- flat-wound coils and aluminuim formers were coming to the fore to get a lot more from the product.

It was fun burning speakers out on purpose

In the case of passive cross-overs it is the higher harmonic that tends to kill off tweeters as DC cannot pass through a capacitor (the feed to the treble unit)

If it is an active crossover in circuit, (before the amplifier) the output from the amplifier is raw and connects straight to the tweeter. Instant BBQ - or 2 Pico seconds of red hot sunshine as the coil turns from copper to carbon.

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