Taming loud mid horns

[hexa]

I replaced all drivers in a cheap pair of loudspeakers because half of them were blown.
So I purchased new woofers, mid horns, tweeters and crossovers. All drivers are probably the cheapest you can get except the crossovers which are relatively decent (visaton 3/80 NG, 1.6kH - 6KHz). Of course I don't have any great expectations, but the horns are very loud compared to the other drivers. Is there any way to reduce their loudness?

 

[mhardy6647]

Add an L-pad (fixed or variable) between the crossover & the driver.
You'll need to know the nominal impedance of the midrange driver on the horn.

Variable L-pads:
https://www.parts-express.com/cat/speaker-l-pads/306

Fixed L-pad calculator:
http://www.sengpielaudio.com/calculator-Lpad.htm

 

[savatage1973]

+1 on the variable L-pads (resistors) to tame the mids and highs--many speakers have implemented them in the past, and continue to do so.

 

[hexa]

Add an L-pad (fixed or variable) between the crossover & the driver.
You'll need to know the nominal impedance of the midrange driver on the horn.

Variable L-pads:
https://www.parts-express.com/cat/speaker-l-pads/306

Fixed L-pad calculator:
http://www.sengpielaudio.com/calculator-Lpad.htm

Thank you hardy! I think I'll get the variable one.

 

[mhardy6647]

Thank you hardy! I think I'll get the variable one.

15 watt is probably fine; if you have any concerns, go for 50 watt.
Are your drivers 8 ohm? Be sure to get the right impedance (4, 8 and 16 ohm should all be available).
The L-pad provides level attenuation without changing impedance. That way, there is not alteration of the crossover properties (frequency response) as the level is adjusted. The L-pad should be nothing other than a volume control for the midrange driver.

+1 on the variable L-pads (resistors) to tame the mids and highs--many speakers have implemented them in the past, and continue to do so.

yup

DSC_7289 (3) by Mark Hardy, on Flickr

 

[hexa]

Yes, they are all 8Ω and in the 100W range while the amp is 20W, does this mean that I should get higher wattage L-pad? I 'm trying to find it locally but no luck yet. I only find an Eminence which is expensive.

 

[mhardy6647]

There won't be much power getting to the midrange; 50 watts is plenty unless you're running PL700B amps or suchlike
If you're in the US, get 'em from PartsExpress or Madisound. Ex-US... you'll have to shop around.
(or try eBAY)

 

[hexa]

I have to shop around. Even internet is useless in this case since most search results I get are about i-pads. Speakers for i-pads.

 

[mhardy6647]

https://www.google.com/search?safe=.....2.15.1408.0..0j0i131k1j0i10k1.0.b33Pc05xdK4
I get L-pads; there's always amazon, too, you know? Or alibaba if you live... elsewhere.
https://www.amazon.com/s/ref=nb_sb_...ttenuator&rh=i:aps,k:speaker+l-pad+attenuator

 

[hexa]

Is this calculator correct if I want to DIY it?

http://www.sengpielaudio.com/calculator-Lpad.htm

 

[slimecity]

Is this calculator correct if I want to DIY it?

Yep I use it all the time.

You just need to have in mind the reduction in dB that you are after. 3db is a noticeable decrease, and 6db is even better. If your horns are waaay too loud, you could aim for say, 9dB reduction. You really need to try a couple of combinations to see what sounds best.

 

[hexa]

I was thinking starting out with 3 to 6 db and when I checked the prices of the resistances @ 50W I turned down the plan immediately. Then I thought buying resistances about 7W which are a lot cheaper and just connect them in parallel to split the power across the multiple resistances. Does it work this way, is the power distributed in a parallel resistance circuit?

 

[slimecity]

Most of the power is used by the woofer. Dont quote me on this but using a couple of 7W resistors in an L-pad for the mid, so long as you arent driving them too hard, should be fine. You can only set it up and then monitor how warm they are getting.

Someone else may chime in with some calculations confirming the minimum wattage you will need for these resistors

 

[hexa]

Now I'm thinking it again, you're right, maybe 50W L-pad is too much for an 20W/channel amp.
3.9 and 8.2Ω @15W would cost 3euros all 4 resistors which give about 6dB. I'll get these and monitor their temperature as you said. Even If I have to try with different resistors to achieve the desired dB the cost will be low anyway

 

[mhardy6647]

Most of the power is used by the woofer. Dont quote me on this but using a couple of 7W resistors in an L-pad for the mid, so long as you arent driving them too hard, should be fine. You can only set it up and then monitor how warm they are getting.

Someone else may chime in with some calculations confirming the minimum wattage you will need for these resistors

Absolutely; the amount of power that is actually delivered in the midrange and treble is much less than that delivered in the low frequencies (for almost all kinds of music) by the amplifier.