Pioneer HPM-100 successful crossover mod!
- Thread starter mattsd
- Start date
Note i am NOT affiliated with Audio Lab....thanks to this forum, i have rebuilt an sx-1050 and got it working great....found a real nice pair of HPM-100Bs to run with it (considered others but wanted to match the late 70s look), and played it with original CXs...it hurt my ears after 10 minutes and vocals were not good....bought a second set of CXs so as not to alter the originals....updated that with new components original cap and resistor specs....also replaced the mids from an HPM 60...still couldn't listen to it for long.....long story short, i took the gamble and read pognoots referenced Audio Lab article and decided to go for it...made a board CX...the super and tweet i managed to fit where the original CX was located, the mid and woof in a board at the bottom of the cab....for ME, these speakers now sound balanced and great now...no more listener fatigue...vocals are clear, and much improved spacial separation....yea i paid a little north of $300 to buy the components for the boards but i was worth the effort as a learning experience and making my speakers "listenable"
xXColdShotXx
Active Member
Is there an alternative for 667-ECW-F2154JAQ? They are out of stock at mouser and have a 43 week lead time.
Pageplayer
Active Member
I went with an electrolytic.. 647-UKL2AR15KDD
I figured this would be fine, since you cant hear the Super Tweeter anyway.
Just sayin.
mattsd
Super Member
You can use a 667-ECW-FD2W154J4.
I picked up a set of HPM 100's on the cheap. That could be the problem. I have yet to find a drawing showing actual speaker Impedance. ie 4 ohm - 8 ohm. Before I put the money into building new crossovers I questioned readings. I measure 4.8 ohms at both rear input connection terminals on both speakers. Is this due to crossover or are the speakers shot? Measured individually speakers 4.6 to 6 Ohms.
RxDx
Speaker collector
You're seeing the difference in DCR (DC resistance, that you measured), vs
impedance (AC resistance), which changes based on the frequency of the
signal to the driver. DCR is typically that much lower than impedance.
Your drivers sound like they're fine. Your measurements can't predict distortion,
but at least they aren't shorted out (or open)
impedance (AC resistance), which changes based on the frequency of the
signal to the driver. DCR is typically that much lower than impedance.
Your drivers sound like they're fine. Your measurements can't predict distortion,
but at least they aren't shorted out (or open)
Just wanted to add my endorsement to @mattsd ’s crossover mod here. I tried to like my HPM-100s for a few years, but couldn’t get them to image or sound all that great. After several weeks of hemming and hawing (and toying with another, much more expensive complete overhaul), I modified them according to this post about 9 months ago, and have absolutely loved them since. What a soundstage now! The speakers disappear. If you’re on the fence, do it!
Joth
Member
I've done this mod a few months ago but... still not where I'd like them to be. The upper mids are so strong I am dialing the mid knob almost all the way off, and of course feel I am wondering thats spoiling the mids lower output.
My question to the OP or anyone else in the know, what can be done to tune the mid circuit itself, can an inductor or capacitor be added to create a bandpass for the midrange instead of just the capacitor highpass.
What would an appropriate upper mid freq cutoff be to suit and not overlap the tweeter?
My question to the OP or anyone else in the know, what can be done to tune the mid circuit itself, can an inductor or capacitor be added to create a bandpass for the midrange instead of just the capacitor highpass.
What would an appropriate upper mid freq cutoff be to suit and not overlap the tweeter?
Hi Joth, I don’t have an answer for you, but I can confirm that I also have both mids and high dialed way down. Mid at -5.5 and highs at -3. That bothered me at first, but they’ve sat there for months now and I’m still loving them. I’m interested to hear any suggestions from others.
Joth
Member
Well here is what I'm doing in the meantime-
I had done the crossover mod listening to each step, and observed the following: when I changed the mid cap from to 4.4uf to 10uf, this was the worst thing ive ever heard in my life, there was a huge volume jump in high mids, not an even-volume extension of lower mid content from the midrange as I expected.
Adding in the 0.9 inductor somehow calmed this down and the bass and low mids returned to a reasonable balance, and this the state of my previous post, just too much treble and upper mid blare, I will say that CDs behaved alot better than the phono, where some pressings are fine and some just unlistenable.
My recent trial was to return the mids cap to 4.4uf, while leaving the 0.9 inductor in place. So far this is the setup I am happiest with, there is a reduction in volume across the entire mid band, the upper mids stay within a reasonable volume threshold, there is more 'space' and clarity between instruments, and I'm certain that the channel separation and soundstage is far improved and dimensional. The CD player now is more consistent with the phono preamps. I tried this again with upping the mid cap to 7uf, but the result was too close to the 10uf behavior and i returned to the 4.4uf.
So unless I find further bandpass type mods, this is the setup I will keep.
info- room is 14x14ft, probably the smallest space these speakers should be in
all listening comparisons with the mid+trb levels set at 0
setup is EAR834 copy, refreshed dynaco PAS3X, dynaco curcio mk3s, various old shure, ADC qlm, AT cartridges
I had done the crossover mod listening to each step, and observed the following: when I changed the mid cap from to 4.4uf to 10uf, this was the worst thing ive ever heard in my life, there was a huge volume jump in high mids, not an even-volume extension of lower mid content from the midrange as I expected.
Adding in the 0.9 inductor somehow calmed this down and the bass and low mids returned to a reasonable balance, and this the state of my previous post, just too much treble and upper mid blare, I will say that CDs behaved alot better than the phono, where some pressings are fine and some just unlistenable.
My recent trial was to return the mids cap to 4.4uf, while leaving the 0.9 inductor in place. So far this is the setup I am happiest with, there is a reduction in volume across the entire mid band, the upper mids stay within a reasonable volume threshold, there is more 'space' and clarity between instruments, and I'm certain that the channel separation and soundstage is far improved and dimensional. The CD player now is more consistent with the phono preamps. I tried this again with upping the mid cap to 7uf, but the result was too close to the 10uf behavior and i returned to the 4.4uf.
So unless I find further bandpass type mods, this is the setup I will keep.
info- room is 14x14ft, probably the smallest space these speakers should be in
all listening comparisons with the mid+trb levels set at 0
setup is EAR834 copy, refreshed dynaco PAS3X, dynaco curcio mk3s, various old shure, ADC qlm, AT cartridges
A friend has original everything in his HPM100's and they sound quite good. Only one electrolytic in the whole shebang, and it's on the supertweeter which doesn't matter anyway. I've recapped a pair, and looking back I'd say, leave em be. Pioneer did a pretty good job. There is a reason that so many of these speakers sold.
z-adamson
Addicted Member
Yes, because of how they compared in store during auditions. The bright highs, foreword mids and boomy bass made them stand out.
Nothing to do with a stellar cross over design from the get go.
Maybe but I haven't heard any mods beat the original yet.
z-adamson
Addicted Member
I
the mv audio labs one is pretty good. Huge step up if you prefer a flat response
dingo1670
New Member
I’m doing this too my pair right now. What happens to the Super Tweeter?? I know most can’t hear it, but I actually can (easier to hear with all other speakers off). Is it not used just as the Potentiometers? Thanks!
dingo1670
New Member
Not even the MV Audio Labs?? Quite few Happy Listeners from that one!
arcorob
Addicted Member
I have followed this thread for several years and I am a bit confused on the listening experience which seems to differ from mine. I love my HPM-100's 200watt version and I never found the mid's or highs too forward...Only the somewhat boomy bass. In fact, I felt I needed more High and Mid;s ..something was missing..I even bought all the parts to redo the crossovers (modify not build new) but have not been able to get myself to dare it (and hey, I restore amps so this should be cake, right?) . So what did I do.
STACK. I have the HPM 100's on the floor and on top of each, a JBL stage 530 and run all 4....The sound is amazing. It delivers what I felt was missing. Now most of you will say I am crazy. I prefer to think maybe my hearing is skewed (lol) but others have heard it also. I will let them listen then turn off remote, vice versa, turn off main. Individual pairs, okay. But the 4 ? ANyway, if anyone builds pop in crossovers so I dont destroy mine, happy to try them ..my garage rig
