10" fart out

reverendrally · #1 12-29-2010, 05:26 PM

Hi all, I have an ongoing issue with a 1x10 cab that I have. It's a sealed I bought the cab some years back with a blown EV guitar speaker in it. I swapped a 150watt eminance bass driver into it and have mostly used it on it's own for small gigs in a sealed configuration. All up it cost me like $170 at the time. However, I also bought it to run on top of a TL for the extra presence a 10" brings in the top end and that's where I've had dramas. I can't get anywhere near flat out on the amp (labsystems 250b) before the speaker starts to fart out below about B on the A string. I tried putting a 222uf cap in line to try and cancel out some of the lower freq and keep it happy, but at higher volumes not even that helps. I also tried porting the enclosure, that didn't help either. So, I'm running some compression to stop the initial fart-out on lower notes. Sounds ok, and it helps some, but there is still a clip. It's pretty frustrating.

Any ideas? Do I need a proper crossover? Is it just gonna be a tale of sadness? I rather not buy a 2x10/4x10. They weigh more, take up space and cash is pretty thin on the ground around here at the mo.

BurningSkies · #2 12-29-2010, 05:31 PM

You're just asking too much for a single little 10, especially when combining it with a larger speaker that can take more volume...

honestjohnny · #3 12-29-2010, 05:34 PM

You need a 2-way crossover. Send the highs to the 10 and the lows to the 15, set crossover to 500 Hz and adjust to taste

BurningSkies · #4 12-29-2010, 05:41 PM

Quote:

Originally Posted by honestjohnny

You need a 2-way crossover. Send the highs to the 10 and the lows to the 15, set crossover to 500 Hz and adjust to taste

Only if the 10 actually works as a mid speaker...depending upon the 10, you're just as likely to get a mess.

RickenBoogie · #5 12-29-2010, 06:06 PM

+1 to asking alot of a single 10, and also, if the box was originally designed as a guitar cab, it won't be near big enough for a 10" bass speaker anyway.

DukeLeJeune · #6 12-29-2010, 06:26 PM

Take a look at the recommended enclosure size on the spec sheet for whatever Eminence woofer you have. My guess is, your enclosure is larger than recommended for a sealed box, and as a result the driver is going into premature over-excursion. If no sealed box size is given, then that woofer is not recommended for use in a sealed box. The box you have may be too big even for a vented box; looks like about two cubic feet to me. As box size goes up, excursion-limited power handling goes down.

A series capacitor will only work as predicted into a resistive load. A speaker in a sealed box has a major impedance peak that cannot be addressed just by throwing more capacitace at it; a tailored multi-element high pass filter is required. A speaker in a vented box has two impedance peaks, making a protective passive high-pass filter even more complicated.

smoov · #7 12-29-2010, 07:29 PM

heres a little trick... get some regular old Elmers glue...thin it down a little with water....get a "acid" brush or something suitable and apply the glue to the cloth surround ONLY. this will help stiffen up the surround, smooth out the response and will help it take a little more power. I've use this on speakers up to 21"...works great.

honestjohnny · #8 12-29-2010, 08:13 PM

Quote:

Originally Posted by BurningSkies

Only if the 10 actually works as a mid speaker...depending upon the 10, you're just as likely to get a mess.

True, the OP's situation is less than ideal for a number of reasons. But trying the crossover will hurt less than the whole truth....

billfitzmaurice · #9 12-29-2010, 08:57 PM

Quote:

Originally Posted by smoov

heres a little trick... get some regular old Elmers glue...thin it down a little with water....get a "acid" brush or something suitable and apply the glue to the cloth surround ONLY. this will help stiffen up the surround, smooth out the response and will help it take a little more power. I've use this on speakers up to 21"...works great.

It also will raise Qes, Qms, Qts and fs and Vas, lowering sensitivity and resulting in less low end output, not more. Not a good idea.
OP, Duke's advise is the only way to go.

smoov · #10 12-30-2010, 07:00 AM

Quote:

Originally Posted by billfitzmaurice

It also will raise Qes, Qms, Qts and fs and Vas, lowering sensitivity and resulting in less low end output, not more. Not a good idea.
OP, Duke's advise is the only way to go.

at that point, what have you got to loose ? Bottom line, I have done it to many new and tired speakers. and it works.. Manufactures use it all the time, and trust me they dont use a measured amount on the surround. Ive to EV's recone class and they just glop it on. They even told us to add more if you hear any kind of surround "tick" or other weird tones. So I doubt it will the change the parameters that much..

reverendrally · #11 12-30-2010, 03:27 PM

I've had someone look at the speaker specs and the cab and believe it or not the cab is too SMALL. Anyhow. I think the root problem is that it's just not up to the task being a single 10 vs a MM stingray 5. So ebay maybe the answer, then I'll start saving I guess.

JimmyM · #12 12-30-2010, 05:02 PM

Quote:

Originally Posted by smoov

at that point, what have you got to loose ? Bottom line, I have done it to many new and tired speakers. and it works.. Manufactures use it all the time, and trust me they dont use a measured amount on the surround. Ive to EV's recone class and they just glop it on. They even told us to add more if you hear any kind of surround "tick" or other weird tones. So I doubt it will the change the parameters that much..

you also recently said you can underpower a speaker and blow it. bill is a longtime cab designer whose life's work has been designing high end speaker cabs and pro audio systems. you promote the long-disproven myth that you can blow a cab with too little power. i'd go with bill's advice, no offense.

GrowlerBox · #13 12-30-2010, 05:16 PM

Quote:

Originally Posted by JimmyM

you also recently said you can underpower a speaker and blow it. bill is a longtime cab designer whose life's work has been designing high end speaker cabs and pro audio systems. you promote the long-disproven myth that you can blow a cab with too little power. i'd go with bill's advice, no offense.

Dude, way to call it! You can run, but you can't hide, smoov!

JimmyM · #14 12-30-2010, 05:21 PM

lol! hey, not trying to embarrass anyone here or anything, but seriously...

smoov · #15 12-30-2010, 08:56 PM

no embarassment here....and yes you CAN blow a speaker with too little power...if your clipping the amp constantly causing the amp to go DC...it will burn out. See it all the time. I know Bill has been around a long time and you dont know me but...I've been reconing speakers and repairing electronics for approx 17 years so I have seen close to every type of speaker failure.
btw jimmy, what did my statement of putting dampening compound on a speaker have to do with your comment?

billfitzmaurice · #16 12-30-2010, 09:07 PM

Quote:

Originally Posted by smoov

..and yes you CAN blow a speaker with too little power...if your clipping the amp constantly causing the amp to go DC...

No amp ever goes to DC, unless it's by blowing the output transistors, sending the rail voltage direct to the output. No speaker ever sees a flat topped square wave either; the voice coil inductance makes that impossible.
As for the glue thing, doing what you propose with a white woodworking glue will totally muck up the works, as it sets too hard. The only valid use for white glue with speakers is as a cone coating when thinned.

smoov · #17 12-31-2010, 05:01 AM

Bill, I have seen on a ocilliscope amps squareing off at the top and bottom of the wave, while this may not be true DC it is a period of time when the voltage is flat lined and at that moment the speaker stops its travel....the harder it clips the longer it stops and cooks....mimicks dc to me. When you see your cilp light come on....guess what..its a flat top squarewave. And I wasnt talking nor did I ever say "woodworking" glue...regular white school glue dose not get hard.

billfitzmaurice · #18 12-31-2010, 08:02 AM

Quote:

Originally Posted by smoov

Bill, I have seen on a ocilliscope amps squareing off at the top and bottom of the wave.

An oscilloscope trace is the only place those waveforms are ever seen. Do you know what inductive reactance is and how the inductance of a voice coil affects driver response? I think not. Read this:
http://billfitzmaurice.info/forum/vi...hp?f=10&t=1886

Jerrold Tiers · #19 12-31-2010, 09:47 AM

The concern over impedance peaks vs a crossover is , I believe, misplaced here.......*

A good crossover frequency for a 10" is going to be well above any credible box tuning or speaker resonance. Your main problem may not be with box or resonance peaks, but rather with the normal increase of impedance with frequency, due to voice coil inductance.

That may not be a 'real" problem if your demands are not very extreme.... if you want the 10 to add some high end to a larger LF cab, figure to cross over above 250 hz, maybe higher. In that range, you are well away from resonances in most any case, and you CAN use a simple capacitor.

For an 8 ohm 10", 300Hz crossover will be about 60 microfarads..... your 222 uF probably was more like 90 Hz, which is still low for your usage. That's particularly true since the 6 dB/octave rolloff really does not cut a lot even at 40 hz.

Your other problem will be adding a second speaker, and possibly going below the amp's minimum impedance.... because the4 second speaker, above crossover, is basically paralleled, unless a second element 'disconnectes" the LF. at 300-500Hz, the speakers typically have not increased in impedance much, so you are better off with a 2 element crossover if you want a 'quality engineered" system. That may not be a big concern if you just want a 'working" system and your amp can handle it as-is.

Blowing speakers at low power.....

Well, you CAN blow a speaker with an amp well under the power the speaker nominally handles....... in a ported box..... but it isn't what the other guy said.

Just drive it at well under the box frequency...... the speaker will get its suspension stretched, AND while the coil is sticking out of the gap, it can fry..... depending on top plate, coil length, etc, etc. A speaker of a couple hundred watts nominal may be destroyed by a 40 watt amp that way.

*... aside from Ampeg, I have also spent a number of years designing commercial PA speakers, a lot of that is carefully matching crossovers and speakers, impedances, power handling etc.....

JimmyM · #20 12-31-2010, 10:49 AM

Quote:

Originally Posted by smoov

no embarassment here....and yes you CAN blow a speaker with too little power...if your clipping the amp constantly causing the amp to go DC...it will burn out. See it all the time. I know Bill has been around a long time and you dont know me but...I've been reconing speakers and repairing electronics for approx 17 years so I have seen close to every type of speaker failure.
btw jimmy, what did my statement of putting dampening compound on a speaker have to do with your comment?

just the fact that bill has been pretty infallable with his advice and knows his stuff probably better than anyone i've ever seen and can back it up with hard info that proves what he says. it only makes sense that you're going to reduce parameters if you add glue to a speaker.