|Speaker System Building Tips. Frugal Low Cost
While reading up on speaker system building I noticed a lack of frugal tips. Many sites are concerned with high-performance high cost do it yourself DIY speakers system kits.
You won't see me mention WalMart or RadioShack due to the very low quality parts they provide.
Things to know:
Four speaker systems can sound much better than two. Setup your front speakers with left channel speaker on the left and right on the right. Place the rear speaker left channel on the right and the right on the left.now as you move in the room and face different directions you still get stereo.
Speaker Power can be very misleading and little no indication of speaker quality. If you see a speaker pair listed at 200Watts. This often means PEAK power per pair. In reality the effective power (RMS) for each speaker would be: 200/2=100W Peak divided by 4 = 25 Watts RMS
dB. Decibels, is a measurement of sound pressure, hence loudness of a speaker. An 88dB speaker is 1/2 the loudness of a 91dB speaker. Your stereo has tone controls for bass and treble (and very good if you have midrange). These tone controls may show +10dB. 10dB mean 100 times the power. This means your 20 Watt stereo at half power (10watts) with the bass turned to +10 can produce 200 Watts of bass power!
Woofer considerations. By physical limitations woofers produce irregular sound waves that leave holes in music or boost some sounds too loud. There are complex ways to correct woofer errors, but the frugal way is to limit the woofer's frequency response to below 400Hz. Most 2-way speaker systems force the woofer to play sounds until the tweeter kicks in at the higher ranges. A bad choice. See off-axis links
Midranges are what sadly lacks in most speaker system you can buy, especially in car speakers.
Tweeters tend to be very loud. see dB. 96dB is common in cone tweeters. I love low cost cone tweeters over domes because they give a clean bell / cymbals sound and they disperse the sound in a wider area.
Phase is very important in sound waves, for when sound waves of opposite phase collide they (nearly) cancel each other. Test the phase of your speakers by setting your tone controls to -10 bass and -10 treble, dial in an AM radio station. Place speakers 1m apart and listen to them by placing your head 1m away between them. Now move your body slightly to either side. If the sound sounds like it is first coming from the centre and slowly moves with your movement you are ok. If the sound jumps way to one side then you are out of phase and you should reverse the + - wires on one speaker.
Tone Generator Software. A free demo package for M$ windows (there are others for linux that I haven't tried yet) exists called NCH. Plug your sound card output into your stereo's TAPE IN (1/8" stereo cord to RCA needed). Set your stereo to flat bass and treble. Volume level 25% to test speakers.
|3 -way speaker system. Front System
Specs: 32" high, 8.5" wide, 10" deep
Response: 60Hs or lower -15k
Power RMS: 20 watts
Parts: I like Parts Express
The tweeters will be installed in pairs and in series. One 10 ohm resistor across the + - tweeter contacts on the crossover will tame the very loud tweeters. A simple solution. One tweeter is mounted high in the enclosure and the other is placed high in the side of the box. This gives outstanding imaging and stereo separation.
|2-way speaker system. Rear
to be designed
created: 2004-04-21 (long overdue!)