Hey guys, I have a 400watt compression horn driver and I need to build something to drive it to a volume of about human voice. I was thinking it to be along the lines of input (for my guitar), volume, and output (for driver). Basically an amp with no speaker just an out put.
(I guess this would be called an amp head? Idk)
(I guess this would be called an amp head? Idk)
What is the senitvity of your intended speaker / horn?
To get to the level of a human voice does not take much power / watts.
For a normal sensitivity speaker ( ~ 88-90 dB SPL )
probably only 0.1 Watt or so.
A speaker with 90dB sensitivity puts out 90dB .. at 1 Watt ( 2.83Vrms output into 8 Ohm ).
And 90dB is LOOOUUUD!!!
Regards
To get to the level of a human voice does not take much power / watts.
For a normal sensitivity speaker ( ~ 88-90 dB SPL )
probably only 0.1 Watt or so.
A speaker with 90dB sensitivity puts out 90dB .. at 1 Watt ( 2.83Vrms output into 8 Ohm ).
And 90dB is LOOOUUUD!!!
Regards
lineup said:What is the senitvity of your intended speaker / horn?
To get to the level of a human voice does not take much power / watts.
For a normal sensitivity speaker ( ~ 88-90 dB SPL )
probably only 0.1 Watt or so.
A speaker with 90dB sensitivity puts out 90dB .. at 1 Watt ( 2.83Vrms output into 8 Ohm ).
And 90dB is LOOOUUUD!!!
Regards
Just buy a cheap amp off ebay or from an online store.
Anything below 50 watts would do the job fine with plenty of overhead.
You could get away with less watts but I find you lose some transient response with lower wattages.
a horn that efficient only needs 1 watt or less for the application you're describing. 50 watts would give you about 121db SPL. that's 104db + 17db (for 50 watts. i took 100watts=20db, subtract 3db (for cutting in half to 50 watts)=17db.
121db is just above the threshold of pain. if you're simulating a normal human speaking voice, go with a good 5 watt amp.
121db is just above the threshold of pain. if you're simulating a normal human speaking voice, go with a good 5 watt amp.
My line 6 spider III 30w amp can drive the horn driver alone at a pretty decent volume, however, since I'm using it in a talkbox and it has to run through about 10 ft of vinyl tubing by the time it reaches my mouth its so quiet I can barely hear it. 
But I found my dads old JVC JR-S300 Mark II stereo receiver and when I plug it up to that and turn on the radio it gets about the right volume.
I don't know what the output wattage is on the JVC but my dad seems to think its around 50W. I has some information on the back but I couldn't find a clearly marked output wattage.
But I found my dads old JVC JR-S300 Mark II stereo receiver and when I plug it up to that and turn on the radio it gets about the right volume.
I don't know what the output wattage is on the JVC but my dad seems to think its around 50W. I has some information on the back but I couldn't find a clearly marked output wattage. 
Sorry, this is a horn driver without a horn being employed in an unconventional fashion?
Normally a horn driver actually drives an exponential horn which provides an impedance match to the atmosphere.
Otherwise the apparent volume produced by the driver will be very small. I think you'll get a lot of distortion too, because of the failure to accoustically load the driver and the reflections at the mismatch.
Does the tube connect directly to the driver or is there a change in diameter?
Anyway, please clarify...
w
Normally a horn driver actually drives an exponential horn which provides an impedance match to the atmosphere.
Otherwise the apparent volume produced by the driver will be very small. I think you'll get a lot of distortion too, because of the failure to accoustically load the driver and the reflections at the mismatch.
Does the tube connect directly to the driver or is there a change in diameter?
Anyway, please clarify...
w
No. I have two plumbing parts connect to the open hole in my compression horn driver to the 10ft long 1/2" OD x 3/8" ID Vinyl tubing. Also I've been messing around with it and if my dad is right, and the output is around 50W (I'll know soon enough I've emailed JVC), than I may even want a little more wattage. Maybe something around 60-70 watts or an amp head with a peak of 100w and a volume control so I can get the desired volume.
If you can get enough volume simply by driving it hard, well and good.
I'd be tempted to keep the tube really as short possible as it's obviously pretty lossy, and sling the driver over your shoulder or somewhere with a long line to the amp. Like a bagpipe. At ten feet long the tube must have a lot of resonances at audio frequency, if you think about the length of a flute.
If you're putting 50 watts into it and not getting much sound out, then you have to wonder where enough energy to power a car headlight is going... does the tube get warm?
How 'bout taking a small regular driver and coupling it to the tube with a funnel? A true horn is ideal but a simple cone will give some matching. I've no idea how this might work out in practice, by the way, but it might end up lighter than the horn driver...
Some of it might be technique. The cavity of your mouth has to act like a mini-horn. You probably have to crowd the mike, which might mean no breathing. Dunno, I've never tried ...but the jaws harp is no picnic.
w
Maybe I'll make one of these for myself.
I'd be tempted to keep the tube really as short possible as it's obviously pretty lossy, and sling the driver over your shoulder or somewhere with a long line to the amp. Like a bagpipe. At ten feet long the tube must have a lot of resonances at audio frequency, if you think about the length of a flute.
If you're putting 50 watts into it and not getting much sound out, then you have to wonder where enough energy to power a car headlight is going... does the tube get warm?
How 'bout taking a small regular driver and coupling it to the tube with a funnel? A true horn is ideal but a simple cone will give some matching. I've no idea how this might work out in practice, by the way, but it might end up lighter than the horn driver...
Some of it might be technique. The cavity of your mouth has to act like a mini-horn. You probably have to crowd the mike, which might mean no breathing. Dunno, I've never tried ...but the jaws harp is no picnic.
w
Maybe I'll make one of these for myself.
The more I think about it the more I doubt that the headphones jack that I'm using as an out put is 50w. Because if it was according to http://myhometheater.homestead.com/splcalculator.html my speaker alone should be louder than a Jet flyover at 300 m. And I'd say it's just a tad louder than the human voice when talking.
So by finding out how many watts is being output I can probably estimate how many watts I need for the desired volume. Can anyone help me figure out how many watts an old JVC JR-S300 Mark II puts out of its headphone jack?
So by finding out how many watts is being output I can probably estimate how many watts I need for the desired volume. Can anyone help me figure out how many watts an old JVC JR-S300 Mark II puts out of its headphone jack?
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