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How to increase sensitivity of speakers?


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I have some PA speakers that I refurbished and I am wondering how I can increase the efficiency.

 

From reading a little in the loudspeaker design cookbook it appears that the enclosure does not affect the efficiency of the speaker. so that leaves the driver efficiencies and the crossover.

 

If I were to increase the efficiency of the woofer from 97dB and the horn tweeter from 97dB to say 100dB. Would I truely be increasing the overall speaker system efficiency by 3 dB?

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Originally posted by Zeromus-X

Yes but how exactly do you plan on just "increasing the efficiency of the driver"? I mean, if it was easy to just bump the efficiency up a few notches, the manufacturers would be all over it already.

 

 

I guess I should have mentioned this. I plan on replacing the drivers. I am trying to see how much getting a HF and LF driver that is higher sensitivity will do to the entire system sensitivity.

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Most horn/driver combinations start at about 106dB/1W/1M, so generally that's not the issue (though the low frequency of the HF may in fact be a problem)

 

The low frequency driver has both average and peak efficiency numbers. So, often a driver that has a very flat response may in fact sound louder than a driver that's measured using peak efficiency.

 

The box can affect the apparent efficiency at the low end of the response curve, by placing a more useable bump in the LF response. Also, excessive internal damping materials can affect (positively and negatively) the midrange and mid-bass response.

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agedhorse, You are thinking way too high end. my horn has a sensitivity of 90dB and the LF driver has a sensitivity of 96. I am not sure if that is peak or average.

 

If I upgrade components to high sensitivities, how does that affect the overall sensitivity of the speaker system?

 

Thanks

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Originally posted by blackba

agedhorse, You are thinking way too high end. my horn has a sensitivity of 90dB and the LF driver has a sensitivity of 96. I am not sure if that is peak or average.


If I upgrade components to high sensitivities, how does that affect the overall sensitivity of the speaker system?


Thanks

Either your horn is a piezo or a hi-fi model. I'd try adding a decent horn/driver to that woofer. 96db isn't bad if it is pretty honest.

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Originally posted by tlbonehead

Either your horn is a piezo or a hi-fi model. I'd try adding a decent horn/driver to that woofer. 96db isn't bad if it is pretty honest.

 

 

If it is a piezo, don't forget you'll need a crossover if you go with a compression driver.

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Originally posted by blackba

agedhorse, You are thinking way too high end. my horn has a sensitivity of 90dB and the LF driver has a sensitivity of 96. I am not sure if that is peak or average.


If I upgrade components to high sensitivities, how does that affect the overall sensitivity of the speaker system?


Thanks

 

 

Agedhorse explained the overall effect that a cab can have on apparent efficiency. By replacing drivers the efficiency should increase to the extent that the driver efficiency has been raised. However, you still need to match the driver to the cab for decent overall sound. Just because it's more efficient and louder you can't assume that the sound is pleasing or effective.

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Originally posted by blackba

agedhorse, You are thinking way too high end. my horn has a sensitivity of 90dB and the LF driver has a sensitivity of 96. I am not sure if that is peak or average.


If I upgrade components to high sensitivities, how does that affect the overall sensitivity of the speaker system?


Thanks

 

 

A horn sensitivity of 90dB... wow that's scary no matter how it's measured. I have never seen a horn with efficiency that low. Maybe it's a typo?

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Originally posted by agedhorse



A horn sensitivity of 90dB... wow that's scary no matter how it's measured. I have never seen a horn with efficiency that low. Maybe it's a typo?

 

 

Its a cheap $10 piezo man.

 

Problem is that I can't find a lens size so I can upgrade to a compression driver. I totally understand that I would need to re do my crossover. I am not expecting much from these speakers in fact I probably won't use them onstage. I have just been using them for loud practices.

 

Thanks for the help.

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Actually, I did this exact upgrade a few years ago. Tried to turn a GLi Pro DJ speaker into something worth using. Bought new woofers, Selenium 1" compression driver, nice crossover and a horn attenuator to put the highs back a bit for practice. Worked OK and saved some money, but if I had to do it again I probably just would have purchased new cabinets. I was able to reuse the horn lens.

 

Biggest problem is that I bought awful "Pyle Pro" 90 dB efficiency woofers. I know, I didn't know what I was doing. Talk about killing a powered mixer. With the Yammie Club speakers worked great for practice, with the home made jobbies clip lights galore and a compressed crappy sound that wasn't loud enough. That's how I learned first hand about speaker efficiency. 6 dB's difference between what I made and the Yammie clubs.

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Originally posted by blackba



Its a cheap $10 piezo man.


Problem is that I can't find a lens size so I can upgrade to a compression driver. I totally understand that I would need to re do my crossover. I am not expecting much from these speakers in fact I probably won't use them onstage. I have just been using them for loud practices.


Thanks for the help.

Measure the piezo and maybe I can suggest something.

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Originally posted by abzurd

Actually, I did this exact upgrade a few years ago. Tried to turn a GLi Pro DJ speaker into something worth using. Bought new woofers, Selenium 1" compression driver, nice crossover and a horn attenuator to put the highs back a bit for practice. Worked OK and saved some money, but if I had to do it again I probably just would have purchased new cabinets. I was able to reuse the horn lens.


Biggest problem is that I bought awful "Pyle Pro" 90 dB efficiency woofers. I know, I didn't know what I was doing. Talk about killing a powered mixer. With the Yammie Club speakers worked great for practice, with the home made jobbies clip lights galore and a compressed crappy sound that wasn't loud enough. That's how I learned first hand about speaker efficiency. 6 dB's difference between what I made and the Yammie clubs.

 

 

The reason I started this thread was to get an idea how the individual components affect the sensitivity of the speaker. The loudspeaker design cookbook I am reading didn't supply a good explaination.

 

Anyway I did the same thing. I have yamaha clubs series and they just about drown these out right now. When I 1st got them the woofer was blown and so I replaced it with a carvin P12B. Later I added a crude 1st order cross over.

 

This is my 3rd and final attempt, I am just doing this for fun and experience. I plan to build some home speakers later and so these are my learners.

 

These are actually 3 ways, but I tried to simplify in my example to get my general question answered.

 

7 1/4" by 3 1/10" piezo tweeter. Hole is 5.5 by 2.25, can expand quite a bit.

 

midrange is 5 1/4", current one is 90dB sensitivity. I can't find one over 92dB and so I am worried that that will be a problem. I am half temped to just disconnect it since the tweeters I am looking at are going to be at 98-100dB.

 

Woofer is 12" carvin P12B. I have done some calculations and I need to retune the port.

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Originally posted by blackba



The reason I started this thread was to get an idea how the individual components affect the sensitivity of the speaker. The loudspeaker design cookbook I am reading didn't supply a good explaination.


Anyway I did the same thing. I have yamaha clubs series and they just about drown these out right now. When I 1st got them the woofer was blown and so I replaced it with a carvin P12B. Later I added a crude 1st order cross over.


This is my 3rd and final attempt, I am just doing this for fun and experience. I plan to build some home speakers later and so these are my learners.


These are actually 3 ways, but I tried to simplify in my example to get my general question answered.


7 1/4" by 3 1/10" piezo tweeter. Hole is 5.5 by 2.25, can expand quite a bit.


midrange is 5 1/4", current one is 90dB sensitivity. I can't find one over 92dB and so I am worried that that will be a problem. I am half temped to just disconnect it since the tweeters I am looking at are going to be at 98-100dB.


Woofer is 12" carvin P12B. I have done some calculations and I need to retune the port.

Have you checked Parts Express? They have a number of models that would work without too much modding. Check these numbers,among others(290-534,260-082,260-083) As for the mid,I would probably scrap it and use a larger horn. If not,is there room for a 6 1/2" mid,like the Eminence Alpha 6"?

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Originally posted by tlbonehead

Have you checked Parts Express? They have a number of models that would work without too much modding. Check these numbers,among others(290-534,260-082,260-083) As for the mid,I would probably scrap it and use a larger horn. If not,is there room for a 6 1/2" mid,like the Eminence Alpha 6"?

 

 

Thanks for looking. I do alot of business with parts express and so far that is the only place I looked.

 

I don't think the alpha 6 will fit with a compression tweeter.

 

That eminence looks very nice. I will have to change the woofer's crossover point, but that would simplify the crossover design if I left the midrange disconnected.

 

I probably should do a 2nd order network rather than a 1st order too. Although I though the cheaper pa speakers just used a 1st order. I have a zobel network on the woofer, so I have my impedance rise under control.

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Originally posted by blackba



Thanks for looking. I do alot of business with parts express and so far that is the only place I looked.


I don't think the alpha 6 will fit with a compression tweeter.


That eminence looks very nice. I will have to change the woofer's crossover point, but that would simplify the crossover design if I left the midrange disconnected.


I probably should do a 2nd order network rather than a 1st order too. Although I though the cheaper pa speakers just used a 1st order. I have a zobel network on the woofer, so I have my impedance rise under control.

Actually,the other two that I mentioned sound better than the Eminence,IMO. They are pretty smooth sounding when crossed over at about 3k. And they have a driver only model if you want to use a different lens.

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Originally posted by tlbonehead

Actually,the other two that I mentioned sound better than the Eminence,IMO. They are pretty smooth sounding when crossed over at about 3k. And they have a driver only model if you want to use a different lens.

 

 

I just thought I would post an update, I went with the parts express horn tweeter and it has worked out great. Its like I took a blanket off the speaker, in fact i may need to add some sort of resistor to limit the response a bit. I did a 2nd order network and hooked up the tweeter with the same polarity as the woofer, it was unclear from the loud speaker design cookbook whether to hook the tweeter up with the same or reverse polarity.

 

Anyway thanks for the help, I am pleased with the results. Altough if I had it to do over again I probably would have just purchased a set of speakers, but it was nice rebuilding it.

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Originally posted by blackba



I just thought I would post an update, I went with the parts express horn tweeter and it has worked out great. Its like I took a blanket off the speaker, in fact i may need to add some sort of resistor to limit the response a bit. I did a 2nd order network and hooked up the tweeter with the same polarity as the woofer, it was unclear from the loud speaker design cookbook whether to hook the tweeter up with the same or reverse polarity.


Anyway thanks for the help, I am pleased with the results. Altough if I had it to do over again I probably would have just purchased a set of speakers, but it was nice rebuilding it.

Which model did you go with for your horn tweeter? And about what crossover frequency.

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Originally posted by tlbonehead

Which model did you go with for your horn tweeter? And about what crossover frequency.

 

 

I went with the 5X6" horn, 260-082

 

The crossover was about 3-3.1kHz. I had to comprimise since I couldn't crossover at 1 octave below the woofer's upper limit and 1 octave above the tweeter's lower limit. That's the main reason I went with the 2nd order, since I thought the faster rolloff would be better.

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Originally posted by blackba



I went with the 5X6" horn, 260-082


The crossover was about 3-3.1kHz. I had to comprimise since I couldn't crossover at 1 octave below the woofer's upper limit and 1 octave above the tweeter's lower limit. That's the main reason I went with the 2nd order, since I thought the faster rolloff would be better.

Yes,I was pretty impressed with that model too,as long as you don't need it to do anything below 3K. I'm sure compared to a typical piezo,that it really opened up the sound of your cab.

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Originally posted by Thundercranium
Try to expose the speaker to new age music, and enroll it in some form of discussion group where speakers get together and discuss their feelings.

 

 

You beat me to it man!

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blackba,

 

to answer your question, to increase the efficiency of a driver you'd have to shorten the voice coil. Find someone who recones speakers and ask them to get you an equivalent diameter, but shorter voice coil.

 

Between the magnet and voice coil determines the power rating of a speaker. Drivers are designed with the stiffness of cone, power or magnet, and size of the voice coil to work well together, so shortening the voice coil will only get you so far, maybe up to %50 percent. From my limited understanding is that there is only so much energy that can be in the gap.

 

If you do shorten the voice coil, your speaker might sound a little brighter since the voice coil can now move a little faster. And....you'll get alot more immediacy.

 

The Celestion Alnico Blue is the most efficient guitar speaker I'm aware of. Very, very loud, but only able to handle 15W.

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Originally posted by garageman

blackba,


to answer your question, to increase the efficiency of a driver you'd have to shorten the voice coil. Find someone who recones speakers and ask them to get you an equivalent diameter, but shorter voice coil.


Between the magnet and voice coil determines the power rating of a speaker. Drivers are designed with the stiffness of cone, power or magnet, and size of the voice coil to work well together, so shortening the voice coil will only get you so far, maybe up to %50 percent. From my limited understanding is that there is only so much energy that can be in the gap.


If you do shorten the voice coil, your speaker might sound a little brighter since the voice coil can now move a little faster. And....you'll get alot more immediacy.


The Celestion Alnico Blue is the most efficient guitar speaker I'm aware of. Very, very loud, but only able to handle 15W.

 

 

Thanks for the info man. For some reason in Vance Dickenson's loudspeaker design cookbook, they don't really talk about what determines sensitivity, at least not that I have found.

 

I have a celestion alinco blue in my vox AC15 and you are right it is very efficient. Those speakers are a ridiculous price now.

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