Considering swapping the Civil Defense horn in my Peavey cabinet (Mr. Fitzmaurice?)

[Stinsok]

I refurbed this old Peavey 2 x 15 and it's pretty cool. I would like to sweeten the high end a bit though. I am thinking about covering the hole for the old horn and installing piezos. I know some of you will say don't use piezos, but Bill Fitzmaurice seems to have great success with them. If I did go that route, how many would I need?

[CL400Peavey]

Originally Posted by Stinsok

I refurbed this old Peavey 2 x 15 and it's pretty cool. I would like to sweeten the high end a bit though. I am thinking about covering the hole for the old horn and installing piezos. I know some of you will say don't use piezos, but Bill Fitzmaurice seems to have great success with them. If I did go that route, how many would I need?

If you want a response from Bill you need to go over to his forums as he no longer frequents this site.

[Stinsok]

Who pissed him off? Thanks for the tip though!

[nashvillebill]

That's likely a PA cab actually. Still OK for bass-only use.

I don't think BFM hangs out here any more, too many ignorant know-it-alls came in and tried to argue with him.

Nevertheless, since you've already GOT a horn, personally I'd just leave it in there rather than retrofitting the cab to piezo tweeters. Given the age of that cab, perhaps I'd investigate the crossover going to that horn. If that crossover used a non-polarized electrolytic capacitor, and it likely does, that cap probably could stand replacement. Old electrolytic caps in crossovers tend to dry out and they don't function like they should, meaning they won't pass any mids and highs to your horn like they should.

[CL400Peavey]

Originally Posted by Stinsok

Who pissed him off? Thanks for the tip though!

It was a while ago, some flat earther drama.

[Stinsok]

I bought the cab and matching Musician head from a TB'er. It doesn't have a crossover, just two capacitors between the 15's and the horn.

[T-Bird]

Hi.

Originally Posted by CL400Peavey

If you want a response from Bill you need to go over to his forums as he no longer frequents this site.

^This.

He unfortunately but very understandably quit TB a while back.
He can be still reached through his site, so fortunately the loss is for just the quality of the conversation here, not for the knowledge.

Originally Posted by Stinsok

I know some of you will say don't use piezos

I'd be one of those people who hate piezos with a passion, and I'd advice everyone against using them.

Originally Posted by Stinsok

but Bill Fitzmaurice seems to have great success with them.

If he (or the users of his designs) wanted to acchieve the same controlled directivity with conventional hi-freq drivers and horns he does with his piezo array(s) the cost would be absolutely astronomical.

Originally Posted by Stinsok

If I did go that route, how many would I need?

As many as there is in the BFM arrays.
+ the required cross-over obviously.
IMHO anyway.

Regards
Sam

[Stinsok]

I am not that knowledgeable on the subject, but wouldn't the existing horn be a big o'l piezo? My thought was to remove it and put newer (2 or 4) piezo's in there and be done.

[nashvillebill]

There are some piezo horns, but conventional horns are not piezo, and most folks think they are smoother than piezos.

You can actually keep the horn itself and put in a different driver, look at Parts Express for pro horn drivers.

Those two caps are the simplist forms of a "crossover". They are a high-pass filter, meaning they only let higher frequencies through to the horn. If they are old and aged, they aren't going to pas the higher frequencies like they should. Start by changing them, you can get the exact same value non-polarized electrolytic caps from Parts Express, they aren't expensive.

[RS66LB]

-if you have enough room on the front baffle perhaps you could use a high frequency waveguide type horn -they're actually very inexpensive and work well, connected to a nice extended range 'mid' driver you'd have a noticable increase in articulation without the clicky high frequency artifacts many of the tweeter like drivers exhibit...anyway here's the driver http://www.parts-express.com/pe/show...number=264-204 and here's the waveguides http://www.parts-express.com/pe/show...number=270-308 or http://www.parts-express.com/pe/show...number=270-316

[nashvillebill]

Yep, if the Peavey horn is 1-3/8", then that Selenium driver could possible be a great upgrade over the stock Peavey, even using the stock Peavey horn.

I'd still replace those high-pass caps!

[RS66LB]

Originally Posted by nashvillebill

Yep, if the Peavey horn is 1-3/8", then that Selenium driver could possible be a great upgrade over the stock Peavey, even using the stock Peavey horn.

I'd still replace those high-pass caps!

Great idea -sounds like you'd have a stock looking cab that's actually geared towards bass guitar

[seamonkey]

I'd be curious what Bill has to say.
He might say to measure the cab and see where the frequency response is lacking, and then design in appropriate driver solutions. i.e. adding a midrange may suddenly open up the sound. More than you could do with just EQ.

Some horns, like for good quality FOH cabs have good reach into the midrange. How they work with your cabinet would be a matter of measurement and design.

[christw]

Why not get the model number off the speakers, email Peavey for T/S data, and model the cab? You could use that data to find a horn and crossover that matches the sensitivity of the stock speakers and fills in the frequency gaps.

[AstroSonic]

I would be another person who would recommend against using piezo tweeters.

Piezo tweeters can be used without a crossover because their impedance rises rapidly below 3-4kHz depending on the model. Unfortunately they almost always sound awful when used that way. OTOH, they can sound smooth and well extended with a crossover tailored to their needs. That assumes that you can find good quality piezos. Motorolo stopped making them years ago, and the QC of recent production (by other companies) has been 'inconsistent'.

Those caps you saw in the cab are the crossover.

With crossover caps in the cab, you most likely have a horn loaded compression driver. Most of them have replaceable diaphragms (includes the voice coil). Many cost in the range of $10 - $30 (some a lot more though). You might be able to get a replacement from Peavey at reasonably low cost. Otherwise there are vendors online who carry replacement diaphragms for the more common MI/PA drivers.

The Selenium D250-X is excellent for bass guitar use, provided that you prefer a smooth, high definition sound without 'zing' (thanks in part to its phenolic diaphragm). Check if your cabs compression driver is a 1 3/8" - 18 tpi screw on type (almost certain if its a screw on with about a 3/4-1 inch opening). Could be a 'plug-n-play' solution.

Regardless of what you get for a replacement, you may need to add an L-pad to adjust the tweeter level.

A step at a a time.

Pull the horn and get a brand & model number off the driver. Call Peavey for a replacement diaphragm and/or check online for one. If that's a dead end, consider the Selenium driver mentioned above.

Good luck!

[fdeck]

My only issue with the piezo's is that the pics at Bill's site show them in vertical arrays, for which there isn't space in the OP's cab.

[Stinsok]

Thanks for the input everyone!