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Multi-Way Conventional loudspeakers with crossovers

Taking a cheap commercial spk apart
Taking a cheap commercial spk apart
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Old 18th April 2004, 07:26 PM   #11
tpenguin is offline tpenguin  United States
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Funny you should post this. I was groing impatient with how long it was taking me to complete my own speaker project, so I recently opened up my cheap ($200-$300 per pair) pioneer tower speakers and was relatively shocked by what I found. These are S-H453F-K's if you want to look them up at www.pioneerelectronics.com . Firstly, the cabinet, which virtually rings when you knock on it, is made of the crappiest, low-density particle board I've ever seen. There was no bracing and absolutely no damping material inside. The woofer was at the very top, the passive radiator at the bottom, and the tweeter and dummy midrange in between. The "midrange" is a two-inch polymer cone with no surround (relying only on the flexibility of the diaphram to move, and measured a shocking DCR of 27Ohms! So I'm guessing it's about a 32-ohm speaker with what could barely pass as a refridgerator magnet on the back. playing it by itself (with the .22uF series capacitor attached to it) revealed that it did indeed make sound, but requiring full volume on my gainclone, and the sound that did escape was quite objectionable noise, which I attribute partially to the harshness of the overall sound.

The rest of the crossover consisted of a 4uF NPE cap in series with the tweeter, no low-pass filter (which is ok in theory, but I can't measure the response to say for certain), and the most puzzing part, a 1.3uF ceramic cap in series with the whole thing. I'm certainly no electrical engineer, but from various tables and such, I think that with an 8-ohm load, that should make something around a 15k+ high pass filter, which seems to be a paradox since I did actually hear sound from the speakers. Anyway, on to the free modifications I made...

The only damping material I could line the cabinet walls with was polyfil (which I actually scavenged from an old pillow, lol). This actually turned out to be more of a stuffing than a lining, though. I completely disconnected the midrange, and removed the 1.3uF mystery cap altogether and replaced the 22ga(!!!) wire connecting the woofer with 14-ga monster cable soldered on both ends. I also moved the midwoofer to the bottom, and put the PR on the top. The result was quite surprising. The bass is much more controlled, and goes much deeper. I think I actually turned it into a transmission line of sorts by adding the stuffing and moving the driver and passive radiator. The harshness is gone, and vocals, pianos, etc. sound much more real. I plan to add an active baffle step compensator in front of my gainclone to make up for the lack of it in the speaker. But, from my experience with these crappy speakers, it seems possible to make significant improvements to cheap commercial speakers without spending any money at all.
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Old 19th April 2004, 02:54 AM   #12
thomas997 is offline thomas997  Canada
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wow my cheap no name speakers sound better built than that..

Guess you cant trust brand names.

They were a surround setup I bought at A&B a while ago (5.0).

Actually the towers are made nicely, the surrounds and center are crap. Center has a very small volume, and cant go deep at all. Electrolytics on the tweeters thats it..

Towers are braced very well. Fair bit of stuffing in the top and bottom sections. Crossover is a 3 way with some okay parts, but not designed very well (inductor is too low of a rating).. But no idea if the speakers are any good, a fabric dome, some mids, and a sub..

I can take some pictures if you want of the crossover or speakers. Planning to sell them and build new ones though.

brand is "SEL"

I like your modifications though, basically get better sound for free
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Old 3rd May 2005, 10:18 PM   #13
lopan is offline lopan  United States
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Mirage uses iron core incuctors and wire wound resistors and cheap caps in the M1 design. So before I concerned myself with crossovers upgrades I would do bracing improvements. Then maybe cahnge caps on the tweeters.
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Old 3rd May 2005, 11:04 PM   #14
pinkmouse is offline pinkmouse  Europe
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Taking a cheap commercial spk apart
A general rule for assessing commercial speakers- 10% of the shop price is for materials...
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
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