I cut 10 pieces of white masonite to build crossovers. Here is my draft layout for one channel. Suggestions (and double check) would be more than welcome.
An externally hosted image should be here but it was not working when we last tested it.
I did some testing of Gorilla glue on film coated ply today and a T joint was surprisingly strong. All I did for prep was wet the exposed wood with water, scuff the film and wipe it down with IPA. I am very confident that it will be fine for the dado joints in my build.
Did you resolve the cause of the 10mm gap?
Yes, after chipping all the chemical metal off and sanding back the epoxy there was a 3mm gap when dry fit. I think I used way to much chemical metal which set before I clamped it and I also think the rubber baffle on the driver didn't compress as much as I thought it might.
I've routed out behind the magnets and glued with pl premium. I'm away until Wednesday so hopefully I'll come back to a good bond.
The piece of wood you see is 110 x 70 mm. I could get it down to 100x50 with a PCB. The biggest issues at this point are lead time and cost. I am quite sure these will work fine.
@Duffy. Just that it looks more professional and is easier to use. Performance wise it won't matter much indeed.
@Steve. That's with the piezo tweeters. Wirewound resistors have quite a bit of parasitic inductance, which acts as a lowpass filter. Not something you want when you use it as a highpass filter on your piezos. For this application it's fine.
@Steve. That's with the piezo tweeters. Wirewound resistors have quite a bit of parasitic inductance, which acts as a lowpass filter. Not something you want when you use it as a highpass filter on your piezos. For this application it's fine.
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Saturnus specified Carbon film for piezo tweeters. In this application (PHT-407 tweeters) I don't thin a few uH will matter but let's do the math.
The inductance is between 10 and 20uH (I could not measure directly so I could be off a bit). If we assume I am off by a factor of 2 (40uH) the -3dB point is in the 80kHz region. I don't think that is meaningful in the scheme of things.
Saturnus specified Carbon film for piezo tweeters. In this application (PHT-407 tweeters) I don't thin a few uH will matter but let's do the math.
The inductance is between 10 and 20uH (I could not measure directly so I could be off a bit). If we assume I am off by a factor of 2 (40uH) the -3dB point is in the 80kHz region. I don't think that is meaningful in the scheme of things.
Actually. It's carbon composition or metal film but not carbon film or wire wound with piezos.
Anyway, I normally recommend metal film with the PHT407Ns there's really not going to be much difference if it's wire wound, carbon film or metal film with the PHT407Ns. I wouldn't recommend carbon composition with those though.
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Also, special winding approaches can be used to reduce inductance. I don't know if these appraches are employed or not.
Wirewound resistor » Resistor Guide
Wirewound resistor » Resistor Guide
but digikey has 2 ohm in 3W. So, I figured I would just put two of them in series and get 4ohm with the required power handling.
Actually, I bought several different values (2ohm,4.3 ohm, 6.2 ohm, 8.2 ohm) and was going to hook them up with a dip switch so I could dial in the attenuation--Saturnus had mentioned that some experimentation here would dial in the tweeter in for the type of music you liked.
They were $0.61/each at digikey.
Actually, I bought several different values (2ohm,4.3 ohm, 6.2 ohm, 8.2 ohm) and was going to hook them up with a dip switch so I could dial in the attenuation--Saturnus had mentioned that some experimentation here would dial in the tweeter in for the type of music you liked.
They were $0.61/each at digikey.
Yeah, then I'd want a PCB to make the soldering easier.
In all seriousness, in this application the Dayton Audio resistors will be just fine.
I did some measurements and these resistors are 0.003 to 0.004 mH. That is a factor of 10 smaller than I used in my calculations below. Fc moves to 1 MHz
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