[Paul Spencer]
Plate amps: friend or foe?
Most diy subs use a plate amp and for good reason: they fit nicely into the same box as the sub, they are affordable and they include everything that you need ...
or do they?
Unfortunately, most plate amps have two very annoying shortcomings:
- inappropriate bass boost which nearly always should be removed (in some cases voiding your warranty)
- no rumble filter
It's not difficult to remove bass boost, and some plate amps are available without it. Some even have rumble filters. If you find such a plate amp at a good price, and you want to build it into the box, then it might be just what you want. But in this wiki, I'll present some alternatives.
Pro amps: the brute force bang for buck option
Often the most power for your money will be from a pro amp. Behringer Europower EP2500 is a good example. This is the amp I use. It can provide 2.4kw bridged into 4 ohms, or two channels with 750w into 4 ohms each. The downside to this and nearly all such pro amps is fan noise. This is really an option for those who have the means to either build a "muffler box" (huge hassle) or put the amp in another room and set it up to come on with the rest of the system.
You will have to add on all the necessary filters to integrate the sub properly. Some will see this as a disadvantage, but I see it as a bonus as you can actually choose a unit which will do the job right. In my view, many plate amps lack the flexibility to really integrate your sub properly. You can add on a diy kit, or purchase a pro unit. If you want high power, as an alternative to buying an expensive plate amp, consider a pro amp and put the money you save into a unit such as Behringer Ultradrive DCX.
| Quick review: I once heard a comparison between a high power PA amplifier and a plate amp powering a subwoofer. Playing the same music, the difference in bass authority was immediately obvious. When played at the same volume, there was far more punch when the pro amp was used. I don't know the reason for the difference. Perhaps power supply, perhaps just more power. Perhaps the plate amp was actually clipping. If you have the chance to compare, I suggest you try a comparison changing only the amplifier. You may be surprised at the difference. I leave it to you to decide what is a fair comparison - whether you should compare amps at the same price point, or amps with the same power rating. It really depends what you intend to find out. |
Hifi power amps
I urge caution with using hifi power amps for this application. It's a bit like using a luxury car where a 4WD would be more appropriate. The extra you have spent on its subtle qualities will not be appreciated. A better choice is likely a studio amp such as the Behringer A500 reference amplifier. At its very low price it is hard to beat. The power is generous for mains but perhaps a little modest for a high excursion subwoofer. It is perhaps more appropriate for bi-amped woofers.
Conclusion
There is no "one size fits all" solution. Most will prefer plate amps, but just because they are the only amp specifically designed for subwoofers does not mean they will always be the best choice. The higher power plate amps are often very expensive. For a dedicated room high power applications, the ultimate solution is a pro amp with a digital crossover system.
