Talk Box Filtering

[Bard Morons]

I know this has been discussed on some level before, but I still had a few questions.  I am using this compression driver

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=260-097

and a gentleman from Parts Express told me that to safely run it, I should filter off anything below 1kHz at 12dB per octave.  This sounds to me like a 2nd order Butterworth highpass filter would work for this, correct?  I'm using a Hot Rod Deluxe for this job, so what kind of wattage do I need for the parts?  It's a 40 watt tube amp, so do I need the cap and inductor to be rated at say, 50 watts?  I'm also assuming the filter should go between the speaker out on the amp and the driver, correct?  According to this calculator ( http://www.carstereo.com/help/Articles.cfm?id=9 ), I'm going to need a about a 1.5mH inductor and 12uF cap. 

Am I on the right track or am I off somewhere?  I just don't want to blow the driver, cheap as it is.  Thanks for the help guys.

[petemoore]

http://www.generalguitargadgets.com/index.php?option=content&task=view&id=109&Itemid=139
  Not sure what kind of filtering is needed.
  may sound strange but you could filter highs by putting say a pop filter or other damping in the tube, since you have an 80w driver...a little bit of damping probably won't have you missing much amplitude.
  You may want to experiment with that and/or a touch of shallow slope HF rolloff via simple filter, or adjust a 2 pole filter.
  Connecting it to 'the' guitar amp..?then what do you use for guitar amp without having to switch the speaker back and re-adjust lots of stuff...
  Putting a different amp on the voice box makes sense for a number of other reasons..
  You can have voice box with or without the regular amp sound.
  The signal going into the diaphram can be separately tweeked and left at a good sound setting, fixed bass cut can keep excess currents out of the driver.
  A dedicated diaphram amp can be chosen for wattage, to make the driver go but not blow [80w is morgan enough]. compressor/SS amp or tube amp...might be nice touch, they seem to work better with sustainey sound or fast picking, and distorted signal makes the vowel sounds 'thicker, like anything else [or moreso] takes some tweeking for best results.
  The chosen driver says it goes down to 600CPS, LF response is a good thing to have [be able to choose to have], I didn't read the specs real close...bass at volume blows diaphrams, you want to cut frequency at X point so that bass and the related high currents aren't flowing through the diaphram coil...said short sweet..80w is a better number than 30w in this respect. Bass into HF driver seriously not recommended...but you want ~full sound, this is where the sharp slope HP filter comes in handy.
  I don't know whether to believe the 'talk box can blow the fillings out of your teeth' bit, seemed like serious discussion when I read it, might want to investigate and keep that in mind w/80w driver.
  So...guitar, effects...splitter
  Guitar     amp
<                       
  Tweeked for Talk box amp [w/LP/HP pre-filters]
  ...or...
  Guitar, Splitter...
  Effects to guitar amp
<
  Effects tweeked to TB amp [maybe comp>dist>Lp/Hp filters>amp]
 

[Bard Morons]

Yeah, I was actually thinking that it'd probably be wise to just dedicate a SS amp I have (65w) for the talk box for the various reasons you mentioned.  I really don't plan to use this rig live, but still, it'd be a wise choice I believe.  One more quick question on the HP filter.  Does it matter at all if it's active or passive?  I was thinking of going the passive route but I got to wondering if active would be better for the driver.  As you said, I really don't want any frequency under about 1kHz getting to it.  Oh, and that is a nifty idea with the pop filter.  I may just give that a go and see how it works.  Thanks!

Oh, and another thought I had.  Assuming that I use the clean channel on the amp (i.e. all distortion and other effects come before the pre-amp) I could actually do all the filtering between the effects and the pre-amp as opposed to doing the filtering between the power amp and the speaker correct?  Or does a power amp add harmonic content that would need filtering before it reaches the driver (really only low frequency content would need filtering at that point)?

Thanks!  This has already given me a few more solid ideas.

[petemoore]

  Any one of the suggestions you mentioned will 'work', just a little differently, rolling off bass after the amp...that'd be like passive Xover...I think rolling it before or after pre-amp is a good point at which to do it, in general, rolling off bass early has certain advantages:
  The amplification isn't dealing with high currents associated with LF just to have them turned into heat later.
  either way will work, and 65w amp should have enough push left over after passive losses to work the driver.

[Jered]

  How many ohms is the speaker output you plan on connecting it to?
  Jered

[Jered]

  Just run the driver through your 8 or 16 ohm speaker connection on your guitar head and go. If you don't like how it sounds, then start tweaking it. I didn't do a thing to mine and it sounds great.
  As far as fillings coming loose, that's a load of BS. I've been using mine for years and have had no problems, and I've got plenty of fillings to rattle loose. Just plug it in and enjoy, its a very, very fun toy.
  Jered

[Paul Perry (Frostwave)]

I would just use a standard HiFi type crossover network.
For higher freq piezo horns, used to give small speaker boxes more presence, my friend just uses a cap.

[Jered]

  And for the connection from the driver to the tube, go to Home Depot. In the plumbing section they have brass fittings that will thread right on to the driver, and the tube will push onto the other end. Another tip, put a wrap or two of teflon tape (also in the plumbing section) on the threads of the driver before you screw on that brass fitting. It will keep it from coming loose from the vibration.
  Jered

[Bard Morons]

By the way, I finally got this thing together and it's awesome!  I ended up doing some pre-power amp filtering just for the safety of the horn-driver.  It's a simple little project (even though it took me weeks to find time to put it all together... haha).  Anyways, I'd advise anyone and everyone to try a talk box at some point because it's a great little gadget!  Frampton here we come... haha.