Hi!
I found two old speakers with fullrange chassis. My idea is to build a bluetooth-corner-frankenspeaker out of them. While I don't think they would be exactly HiFi, I thought the typically warm sound with good point-sourcey understandabillity can be achieved. Subjectively they have a certain quality to them and go quite loud, as proven by feedback. Ooops!
I meassured them in their old enclosures and they seem to have some problems:
There is a huge phaseshift when the small cone starts to load at 1kHz, unpleasant harshness caused by the bump around 2,4kHz (?) and uneven hights, which could be caused by my quick meassurement setup.
Good part: despite the issue around 1kHz, phase response is really nice and it seems to me like they only need an EQ around 2,4Hz (-6dB/Q=1 maybe) to get that pleasant warm sound for a kitchen radio.
Next up would be finally soldering my measuring cable for T/S params, designing a BR enclosure out of scrap parts and buying a china bluetooth-dsp-amp board.
One question: is the phaseshift immanent to that kind of speakers?
All the Best! robo-klaus
I found two old speakers with fullrange chassis. My idea is to build a bluetooth-corner-frankenspeaker out of them. While I don't think they would be exactly HiFi, I thought the typically warm sound with good point-sourcey understandabillity can be achieved. Subjectively they have a certain quality to them and go quite loud, as proven by feedback. Ooops!
I meassured them in their old enclosures and they seem to have some problems:
There is a huge phaseshift when the small cone starts to load at 1kHz, unpleasant harshness caused by the bump around 2,4kHz (?) and uneven hights, which could be caused by my quick meassurement setup.
Good part: despite the issue around 1kHz, phase response is really nice and it seems to me like they only need an EQ around 2,4Hz (-6dB/Q=1 maybe) to get that pleasant warm sound for a kitchen radio.
Next up would be finally soldering my measuring cable for T/S params, designing a BR enclosure out of scrap parts and buying a china bluetooth-dsp-amp board.
One question: is the phaseshift immanent to that kind of speakers?
All the Best! robo-klaus
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Quick thought: wouldn't it be possible to eliminate the resonance completely with a notch filter? Think I'll try that!
And the specific amp board is this one:
https://aliexpress.com/item/1005006891658934.html
And the specific amp board is this one:
https://aliexpress.com/item/1005006891658934.html
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additional messurements, driver out of the box. directly up laying on a carpet and diagonally up on the same spot. Meassured various distances, with very similar curves.
Does my interpretation hold? (Whizzercone sets in at 1kHz and unpleasant bump at 2,4kHz)
Well I think the problem may be the cone transitioning to the small whizzer, causing broad cone resonance from midrange to low treble. Test placing a rubberband ring on the cone (driver facing up). Perhaps a coat of dampener or aluminum foil layer (search the fullrange forum). The small whizzer acts higher in frequency.
Or notch twice, 480-900 and 2500-5000. (4ohm-nominal rising impedance) 1.5mH||44uF and 0.3mH||8uF||R-to-flatten.
Or notch twice, 480-900 and 2500-5000. (4ohm-nominal rising impedance) 1.5mH||44uF and 0.3mH||8uF||R-to-flatten.
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if you want to keep the warm sound of a paper cone just try to linearize with a crossover or eq the response.
Aluminium foil trick would transform the driver into a direction of a more modern driver completely.
If you don't mind for this a one layer alu foil on the cone could remedy the resonance of the cone. Use silicone sealant and household glue.
Aluminium foil trick would transform the driver into a direction of a more modern driver completely.
If you don't mind for this a one layer alu foil on the cone could remedy the resonance of the cone. Use silicone sealant and household glue.
if not the wondom internal eq is necessary I use Zk mt 21 from whuzi audio or zk 502 mt they have bass treble and sound perfect with 24v supply can be a smps with at least 150watt
Looks like you are really experienced with that foil trick!if you want to keep the warm sound of a paper cone just try to linearize with a crossover or eq the response.
Aluminium foil trick would transform the driver into a direction of a more modern driver completely.
If you don't mind for this a one layer alu foil on the cone could remedy the resonance of the cone. Use silicone sealant and household glue.
Thank you for the detailed answer!
I'll try out the rubber band trick and fixing it with the internal eq from the Wondom first, which also arrived now. No idea if it is any good, we'll see. I hope I can do some measurements these days and report back 🙂
Best wishes!
Yeah thanks a lot for affirming that! I'll try to notch it away, but will do it active, as the dsp is dirt cheap and I always go fully active 🙂