Looking for advice on building a horn amplifier for a speaker.

I'm looking to build a backpack or box that will have an MP3 player, speaker and phonograph horn.  I want it to look steampunk/victorian style.  I'm planning on just building a good box, and I'm sure I can find a good speaker out there, but I'm not sure how to attach the horn to the speaker and the audio engineering aspects of that.  I'm considering incorporating a tube amp into the mix, and any advice would be appreciated.

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gmoon7 years ago
You're looking for a crossover filter. These are common components in any speaker system that separates audio frequencies for different drivers--woofers, horns, tweeters, etc.

Horns and tweeters need to be protected from the low freq component; either to prevent damage, or to prevent "muddying up" the output.

Passive crossovers are simple, and use only a few components. You can buy em cheap, or build one yourself. You can also go to a thrift shop (like Goodwill) and purchase "beater" speakers and salvage the crossovers (that's a "crap shoot," though--cheap speakers might not even have one.)

Have fun with the tube amp--I've built a couple, and repaired a few. Lots of information on the web. Definitely look to "HiFi" designs over guitar amps--they have too much harmonic distortion for quality audio fidelity...
benjaminmbaker (author)  gmoon7 years ago
Clarification: Looking to build a horn/ tube to amplify/direct a speaker.  Like the ones used on old phonographs.  The speaker building will be incorporated, but its more that I want to make it appear as a box emitting sound through a horn, not just a speaker set up.
If I get a chance, I'll try to post photos of an old horn-type speaker I've got. Maybe that will be helpful.

Re: tubes--they were common in car radios for a couple decades. And guitar amps--they shake and vibrate like mad; and gigging musicians (and roadies) toss them around daily. So they aren't as fragile as you think...
Whilst you certainly used to be able to get shock-proofed tubes/valves I doubt you can anymore, and the power requirements over a modern class D amplifier means I don't think its a terribly good idea to try for a tube amp in a highly portable application.

On making horn speakers, try this link www3.ocn.ne.jp/~hanbei/eng-links.html
benjaminmbaker (author)  steveastrouk7 years ago
Thanks for the link!  Its very useful for the basics.  This will most likely be run from an external battery.  Probably a deep cell or something of the like, more portable in the sense that I can take it with me and use it away from home, or incorporate it into the bike cab I will be riding for some extra pizzaz and better tips over the summer.
Believe it or not most tube are already shock proof enough to use for this application.  During WWII American radio equipment in airplanes and land vehicles were normal off the shelf tube and shock proof equipment didin't come into common use until well into the Korean Police Action.  Can you imagine the vibration thru the airframe of a B-17 in action.

The only accommodation for shock was to use tube retainers to keep them inserted into their sockets.

benjaminmbaker (author)  Re-design7 years ago
Thank you for this information!  It is very much appreciated.  I have seen the rubber vibration dampers, but I have not seen the tube retainers, I will look into this.  I'm wanting to build a stereo system I can incorporate into my summer bike cabbing job to add a little feel, and then something fun for picnics and special events afterwards.