Suitable horn driver for talk box...

[NaBo]

The ratio between "projects i've started" and "projects i've finished" just keeps getting bigger.

I was perusing the talk box section of GGG and decided it'd actually be pretty easy to cook one up, and what effect could possibly be any more fun?

Only problem I have is deciding on a suitable/affordable horn driver...  the one from parts express that Tony Guy used is apparently discontinued, but with a bit of poking around I found this one which seems like it would work... http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=260-097

Pretty darn cheap too.  What say you?

[coma57]

I build a talk box wich is very good to my ears! I choosed the Eminence PSD2002 for it! It'not the less expensive, I'm sure you can find other horn driver wich sound teh same for a lower cost, but it suit very well for this application!
take care to the filter cap, or your hron driver will soon be broken!

[NaBo]

Hmm... filter cap you say?

This is one of those newbie questions that is far-reaching and probably has a ton of info out there on the net to read up on... but...   :oops:

When do you need a filter cap between the output of an amp and a speaker/horn driver/whatever?  I assume it's different from an output cap... Is this accross the + and - wires of the speaker?  How do you figure out the value?

*lopes off with tail between legs* (oh the things I should know but don't)

[PurpleTheory]

I bought that exact one at parts express to make a talk box and it works great. still haven't figured out a very good way to attach the tube to the driver though. i used duct tape  :wink:

[NaBo]

Ahh, good to know!!!  I'll go ahead and place the order tomorrow then!  I figured the specs were pretty much the same as any other that people suggest, but wasn't sure about the "quality" factor.  At a third of the price, "works great" sounds excellent to me  :wink:

About the tube-attachment... I don't know if im actually going to try it, but the thought of using plasticine did pop into my head at some point...  I wonder?

[coma57]

for the filter cap, you've got to calculate it, but I don't have it in mind, but for mine I used 2 8.2µF MKT in parallele!
for the tube, I used some garden equipments, and it works well, all you've got to do is keep it hermetic, airsafe!

[stompbox steve]

I use an old microphone, from a Emerson stereo.  about 10 years ago I plugged it into the output of a boom box by mistake and found out that the music came out.  I then took a black Kodak film case and ducted taped it on over the head of the mic.  The tube goes into the film case.  Works great!  Over the years I have moved it from a old box (arion distorion spray painted black) to a plastic enclosure with a input 1/4 jack and a jack for the tube.  I will post some pics.

Steve

[Rodgre]

I built one with this: http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=260-097 and it worked...

I learned the hard way that you NEED that filter cap, and the person I spoke with when I ordered it calculated it for me so I ordered the two together. I think that driver doesn't want to see anything below 600hz.

Anyway, I fashioned a connection for the hose with a few different doo-dads I found at Home Depot. First, I found a PVC coupling which the tube fit into (I also bought the tube at HD too) which splayed out a bit, small at the tube end, and the same size as the collar on the driver at the other end. How to fasten it though?

Well I found a small piece of rubber hose coupling and used two hose clamps on the hose, tight on the driver's collar, and then tight on the PVC coupling.

To keep the tube tight in the PVC, I just used a strip of duct tape wrapped around the tube, and pushed it in.

It worked well, but I ended up blowing up two drivers with a 15 watt amp. Kind of a bummer. There must be some part of the equation that I'm still missing.

I put the whole thing into a small homemade wooden shoebox with a hole on top for the hose and a jack on the side.

Roger

[Nasse]

Many months ago I got a crazy idea, which I want to share. I have a mobile phone with FM radio and MP3 player and it has quite loud speaker versus size. Sometimes you can find similar speakers as spare parts or at surplus market, dropped off assembly line or on non functioning phone or other device. I just thought if this kind of speaker is loud enough to use it near your mouth and vocal mic, no need of long tubes... Maybe I should try it some day...

Talking about horn drivers, I believe some drivers made for paging/alarm or megaphone might have more low end response, perhaps 300 Hz and up. Medium power PA top drivers  usually are crossed over at 2000 Hz or thereabouts.

And I wonder if you could make a diy driver from some good quality small, like 4", full range speaker in closed box, some kind of small "pressure chamber" in front and take your tube there

[MR COFFEE]

If you are blowing drivers, you need a steeper rolloff 12-18db/oct or higher cutoff frequency.

Amps tend to like it better if you run the lows into a resistor, too. FWIW

[coma57]

for mine, I calculate the filter for 900Hz cut-off at 6dB/oct, that's the same as heil talk-box!

I like the idea with the mic, I'll test it one day!

[petemoore]

Doesn't what goes into it from the amp have a bearing on how much mids the horn is forced to produce or try to produce?
 For horns, my Exp has been 'just make sure the horn is able to do what is 'forced' to do', a little overkill is certainly better than a slight underrating.
 By limiting the amount of lower frequencies the horn 'sees' [~ mids...]by reducing the cap farad value, the horn that's 'on the edge' will be 'inside the safe zone'...bigger horns will produce lower freq's/higher amplitude without blowing.