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Just how bad are cheap aftermarket woofers?

H

HPMguy

Super Member
I got greedy and bought a pair of HPM 500 speakers off eBay without looking carefully enough, and they ended up having had the woofer replaced with some korean make stamped sheet metal bucket woofers. Glued in with silicone caulk, no less.

I re-suspended them (the foam was dead, and I didn't look much past that, if I'd paid more attention I'd probably have passed on them) and they don't actually sound too bad, especially after I plugged the screw holes that were open. Not quite the amazing deep bass of an HPM, but not different enough to ditch them.

Has anyone measured the difference between OEM proper woofers and generic replacements? I'm curious -- I'll replace them with real HPM woofers as soon as I locate a pair.

These are destined for a friend who is short on cash, so I'm not in a hurry, just curious if it's really worth the effort. Might use HPM 40/60 woofers, as they have cloth suspension and much less fragile cones.
 
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I didn't, the PO (or some other earlier owner) did.

They sound muddier than my "real" HPM-500s, or my "new" HPM-900s.

I was just curious to see if anyone had actually measured the differences. I don't have the tools or I'd do it myself.

The real difficulty at this point in time is finding some with intact cones. I can do the foam even if it's hard to find the proper ones, but so far all I see is busted ones.
 
For the fourth time, these ARRIVED with replacement woofers, I didn't put them in. I don't what them in there. SOMEONE ELSE put aftermarket woofers in them.

They do not sound like HPMs -- OK speakers, but nothing special, so I'll be digging up the correct woofers. Will take a while, I can get four or five with broken cones, but what's the point in that?

I hooked them up a/b with my OWN HPM-500s, which have the proper woofers, and the "new" ones with incorrect woofers lack that wonderful midrange and bass the "correct" ones have. Not terrible speakers, but just something you could pick up anywhere for cheap, not that full sound with amazing soundstage I hear with the HPMs.
 
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As a standalone product, I would suggest modern "cheap" woofers are actually well made and well engineered devices, surpassing the performance of many of the woofers of yesteryear. Dayton Audio, Pyle, Goldwood, etc all make excellent products at very reasonable prices.

They may not be the proper design for the HPM series speakers (you reference the midrange capabilities), but on their own, they're quite good.
 
HPMguy - SOME us are hearing you! ;)
Good luck with the hunt for original drivers for your speakers.
Said with no snark implied - don't know if they are unobtanium or not,
honestly, I wish you good luck making them whole.
The HPM speakers are said to be quite fine.
 
You can sit on them and wait until the proper woofers come up for sale.
It may be tomorrow or in years, you never know.

For rare units, it's a matter of principle to find the OEM units and fix them up. Otherwise, the only way to get something acceptable, if possible, is to have T/S measurements of the original woofers and then hunt down possible substitutes that must match both specs and physical dimensions. For circular face, 4/6 screw type common diameter woofers, a physical match isn't that hard. But matching the specs is a must to get adequate performance.
 
SaSi said:
....Otherwise, the only way to get something acceptable, if possible, is to have T/S measurements of the original woofers and then hunt down possible substitutes that must match both specs and physical dimensions.
Click to expand...

Unfortunately that takes care of the bass response but not the quality of the midrange reproduced by the woofer. I'm a-thinkin the OP's best bet, if unable to get original woofers, is to go with a JBL LE-10 woofer; it's noted for excellent midrange. They're not cheap but they're available. Proper integration of the JBL such as retuning the cabinet and crossover might give the OP an excellent speaker if not an original one.

Of course I might be totally off base with that notion, I'm just thinkin' out loud here.
 
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Since the 500 is a two way speaker with super-tweeter, the original woofers are very important. Also used in the 700's, so should turn up some time or other in repairable condition. Mounting is an issue, as the originals have a wide rim with four cut -- square with round corners -- and the screws are pretty far out. Hence the silicone caulk used to stick the cheap replacements in, only 1/8" or so overlap with the holes.

The ones in there are probably cheap (Korean manufacture) woofers with resin impregnated cones, pretty thick and hard. Probably roll off at pretty low frequency, so the midrange has a hole in it and the bottom end is gone. The HPMs are only down a few decibels at 10Hz. These are probably silent, magnet is too small.

I will search. As is, they sound like my dad's old Utah speakers with more top end. Not terrible, but my buddy is a professional musician and will definitely hear the difference! And having a woofer fall out would be a bad thing I suspect.....
 
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From hifiengine: Crossover Frequency: 2500, 8000Hz
Perhaps knowing how high the woofer has to reach, 2,500Hz, will help?
 
The poly/graphite cones of the original woofers are infamous for cracking. If the original baskets were available, they could be re-coned with paper cones, which, if done properly, sound quite good.
Since the originals are gone, a perusal of the Parts Express woofer selections is probably the way to go.
 
I've replaced the foam surround on a couple pairs of those woofers, they are scary thin at the edge and VERY easy to crack. They seem to hold up really well in actual use, but totally unprotected from any sort of impact. Scraping the dead foam off will almost always crack them, it's necessary to use solvent on a soft cloth, with great care.

I'll have replacements re-coned if I have to, would rather stick with the original if I can find them.
 
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