Hi guys, trying to make a pipe boombox using a pair of Monacor DT-90 tweeters and a pair of Viston w-130s 130mm woofers and a pair of 4 inch passive radiators either end along with an old 2 way crossover from a broken up pair of TEAC speakers which according to the calculator should give roughly the right cross over frequency and it is all driven by a TPA 3116D2 and 20v PSU, I have also tried another similar amplifier board with the same result - virtually no bass response.
Just ordered a 32v psu and TDA7498 amp board to see if it makes a difference but concerned it is also going to flop!
Any ideas or suggestions??
Just ordered a 32v psu and TDA7498 amp board to see if it makes a difference but concerned it is also going to flop!
Any ideas or suggestions??
i know it's an amp forum but the OP should verify polarity of the two bass drivers and without a picture of this he could be losing bass because he has two drivers on opposite ends of an approximately 2 foot long pipe...with a passive radiator?? volume of the pipe without increasing length or tuning of the passive radiators is questionable but assuming increasing a supply is going to fix it is also not a good idea.
Lozjek's advice about opening a thread in a loudspeaker forum is what i'd do before messing with the electronics.
Lozjek's advice about opening a thread in a loudspeaker forum is what i'd do before messing with the electronics.
Thanks guys will ask in the speaker section then. Will double check polarity but pretty sure that is OK. With the drivers out of the enclosure there is not a great deal of movement so don't think it is the woofers working against each other, the lack of movement was why I asked in the amp section. Re. Enclosure volume, think you misread, it is about 25 litres.
I did wonder if impedance would cause my issue?
I did wonder if impedance would cause my issue?
to get that volume in a 6 inch pipe it would have to be closer to 4 feet in length.... you reported a length as 58 cm (which is 22 12/16 th give or take)
and yeah "c.25 liters" to me read like a 1/4 liter either way we know enclosure tuning is "off"
and my likely bad math tells my that a pipe 16 cm in diameter 58cm long works out to 11.6 liters...
and yeah "c.25 liters" to me read like a 1/4 liter either way we know enclosure tuning is "off"
and my likely bad math tells my that a pipe 16 cm in diameter 58cm long works out to 11.6 liters...
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Fair shout, obviously put something into the calculator wrong because as point of reference no way this has the volume of my 25 litre fish tank. Either way, accept this is not the next b&w nautilus, just meant to be a boom box which is currently misfiring and I know it is an electrical issue rather than enclosure, just need to find what that is. Will go with suggestions and see what comes of it
depending on design if you turned the amp on without a load connected you could be looking at circuit problems! here have a read TPA3116D2 Amp
Pictures uploaded, think that I may have found a contributing issue, When switching on both woofers move and static comes through both, HOWEVER I only get sound from one channel, wiring for both is fine so think my input cable is causing me issues. Going to get another cable and check shortly.
Attachments
ok that helps
so only one crossover (which by the way looks like it has a funky solder joint on what seems to be the input side)
and if both drivers are sharing the same volume with no partition that's another issue (along with the volume reduced by the half cutaway)
number of wires to and from the x-over does not seem to jive (but if returns are separate then it's me that's in error)
no shame for a work in progress.
so only one crossover (which by the way looks like it has a funky solder joint on what seems to be the input side)
and if both drivers are sharing the same volume with no partition that's another issue (along with the volume reduced by the half cutaway)
number of wires to and from the x-over does not seem to jive (but if returns are separate then it's me that's in error)
no shame for a work in progress.
Sorry that is one of the crossovers - I am using 2
I did however break the PCB of the other so have the components out using but running in parallel with the cap in series for the tweeter and the inductors in series for the woofer will picture if helps, but I have tested with no crossover at all and the woofer is getting no music from that channel which leads me to think it is the input cable
Like turk 182 said, your enclosure is too small. An unknown passive crossover also could be a cause, as it might not suppress the rising midrange response of the woofers.
Assuming an internal diameter of 15 cm and length of 54 cm, the internal volume is 9.54 L which is 4.77 L per driver. Assuming a tuning frequency of 60 Hz, the response starts at 85 Hz -3 dB. That is no real bass though it should have some kick bass.
Commercial bluetooth speakers rely on EQ to get useful bass. They also have woofers with stronger motors, which work better in undersized enclosures. You could add a DSP to add EQ?
Assuming an internal diameter of 15 cm and length of 54 cm, the internal volume is 9.54 L which is 4.77 L per driver. Assuming a tuning frequency of 60 Hz, the response starts at 85 Hz -3 dB. That is no real bass though it should have some kick bass.
Commercial bluetooth speakers rely on EQ to get useful bass. They also have woofers with stronger motors, which work better in undersized enclosures. You could add a DSP to add EQ?
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removal of "conformal" coating is something that threw me for a loop in my noobie servicing days, and after 30 years i still come across all manner of oxidization and contaminants that can cause problems with soldering...probably why i expound on the importance of visual inspection with a magnifying glass...it's scary what a close up look reveals and once you know what to look for it can sometimes make the difference between non functional and HEY it works! all because of one bad solder joint!
with troubleshooting don't fall into making assumptions always look for a quick method of verifying your assumption, simple things like swapping loads or signal lines around to confirm operation (i don't recommend hot swapping signal lines but have done so under controlled conditions) or a "disturbance" test.
too much typing...time for scotch...
with troubleshooting don't fall into making assumptions always look for a quick method of verifying your assumption, simple things like swapping loads or signal lines around to confirm operation (i don't recommend hot swapping signal lines but have done so under controlled conditions) or a "disturbance" test.
too much typing...time for scotch...
Not going to lie, may have green seduced by the "bigger means more" bug and went for the biggest woofers with the lowest frequency response I could fit. So no real science and used a you tube video on how to make pipe boombox. Also the fact I love the sound profile of my psyc Monic bluetooth speaker, which ss you rightly point out will have a dsp. Trying to make a jbl xtreme 2 on the cheap!
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