Looking for specific advice regarding amplification in a 15 or 18" bass reflex subwoofer box. DSP is not necessary. I've been looking at this module: Sure Electronics' webstore 1 x 2500 Watt Class D Amplifier Board - IRS2092
What would I need as far as powering the module? I know I could order Speedwell supplies, but I also know with my hifimediy amp I got another board to use as power supply. What are the differences in these two types of supplies, and which would be better for a prosound application. I could use 4 or 8 ohm driver.
What would I need as far as powering the module? I know I could order Speedwell supplies, but I also know with my hifimediy amp I got another board to use as power supply. What are the differences in these two types of supplies, and which would be better for a prosound application. I could use 4 or 8 ohm driver.
2500 watts is quite specialist.
Maybe a couple of transformers and a bought in rectifier and smoothing caps pcb.
Alternatively a couple of SMPS.
Maybe a couple of transformers and a bought in rectifier and smoothing caps pcb.
Alternatively a couple of SMPS.
and overkill
once you go past 300W it'll be mostly heat and distortion that you are producing, if however you want to produce a lot of bass you're better off using a horn or better a horde of horns.
once you go past 300W it'll be mostly heat and distortion that you are producing, if however you want to produce a lot of bass you're better off using a horn or better a horde of horns.
Excellent advice! I do have a couple of BFM Tuba 36 horns. I was looking to build a single 18 reflex active sub for smaller gigs. Any advice on an off the shelf module/power supply for the reflex cab.?
There are many different 15-18" drivers. Depending on their capabilities and your needs the required power varies much.
That amp is single ended, can produce 2000 W at 2 ohms load, so unless you build the box with 2 pcs of 4 ohm driver paralleled, you wont get the full power.
For such high power I would recommend a full bridge design, because it can deal with the higher load impedance, and doesn't suffer from supply pumping, and safer in case of unintended short circuit, and more symmetrical. There are more possible benefits using bridge, but they depend on the realisation. Further efficiency improvement and more effective storage capacitor arrangement can be achieved if done properly.
This Bridge Tie Loaded amp may fits better the requirements (however lacks the additional benefits I mentioned):
Sure Electronics' webstore 1 x 3000 Watt Class D Audio Amplifier Board -IRS2092
If you want to use the full continuous maximal power, then you need a stabilized and overscaled SMPS as power supply. But I don't think designing for continuous maximal power was a good idea. Both capability of drivers and nature of music dictate that for short time the amplifier should reach a very high power, while sustained high power must be limited (to protect the speaker). In this aspect the traditional power supplies (transformer+diodes+capacitors) are good, just heavy.
I can't recommend any particular PSU or amp module available from global stores, every one I know (not too much) has some drawbacks. Abletec ALP0400 PSU is good and very cheap, but too weak for what you need. Others are much more expensive.
I can recommend only a guide:
2 speakers, 8 ohm, 800 W RMS, 1600 W music power each, paralleled.
1600 W music => rail voltage is more than +/-80V for a bridged amp
This is the calculation: Vrail-rail>Vpeak_out=sqrt(2*P*R)=sqrt(2*1600*8)= 160V. I usually set +/-84...90 V. Rail voltage during continuous load can (and should) drop to 70% = 59...63V.
PSU should be "Resonant", "LLC" or "soft switching" converter. Overload protection must be a "soft" or "current limiting" type, not "switch off", "hiccup", "restart" or "latching". Stabilisation is not neccessary, but ability to drive high storage capacitor is, since additional 10...16 pcs of 1000uF 200V capacitor bank is needed to provide the excess music peak power over the nominal 1600 W.
I guess you mean Meanwell, that is a general manufacturer of Switch Mode Power Supplies. The "another board" I assume mean also an SMPS, for example like this: SMPS2000R +-84V 230V Power supply
The later is specifically designed for power amplifiers, so it would be better, and considering the power its price is quite reasonable, however I wouldn't really recommend it either, because with its high overload limit (2600W) it can fry your voice coils in case of an overdrive. In many other aspect it seems well, soft switching, current limiting type protection, I see soft-start and EMI filter on the PCB. Unfortunately the capability to start-up with additional output capacitor is not defined, and the transformer seems to be strongly coupled, which increases conducted EMI (may cause interference in an other device in the system).
Conducted EMI is treated better in their smaller SMPSs:
http://hifimediy.com/connexelectronic/SMPS500R--45-230V
I've designed and built quite a lot of SMPS and CléassD amplifiers in the past, and I'm going to start it again, If you want, and you can wait for about 6...8 weeks I can modify my current design to fit also your project, and can sell an SMPS+Amp that are designed to work perfectly together, and while producing very high music power, wont harm your drivers.
BTW: a horn loaded driver is not only louder, but generally also safer than a ported desing, because it operates with an acoustic load matched, coil movements are more controlled. A bass-reflex box at (near) the port tuning frequency overdamps the diaphragm, it becomes almost static, and a high current is flowing while there is barely any movement cooling the voice coil. This can fry the driver quite easily, and this is why I recommend lower power limit. The other problem occures at a lower freq, where there is almost no damping, and with a small current you can reach and exceed Xmax, voice coil may hit the magnet back pole, or the suspension may break after a while. Therefore a tuned, steep subsonic filter is recommended for ported boxes if you need high power and reliability at once.
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