Pioneer HPM-100 successful crossover mod!

mattsd

Super Member
I think I have finally figured out the sweet spot for modding the crossovers on these things! I had really been wanting to take the harshness out of the HPM's for a long time and a week ago I decided to do something about it. The current crossover points were about 1600Hz, down 6dB at 3200Hz for the woofer and a staggering 5300Hz, down 6dB at 2650Hz for the midrange with the new 4.3uF poly cap I had in there (I had previously recapped them following the HPM-100 recap thread on here).

I started calculating about what the crossover points would need to be and came up with 2400Hz for the midrange and 1200Hz for the woofer, which would put the midrange down 6dB at 1200Hz and the woofer down 6dB at 2400Hz so one would pick up where the other left off. Of course, that is on paper figures and not real world, using paper figures and figuring 7 ohms to be the impedance of the drivers (which it was, I checked) it would ne667-ECW-F2154JAQed a 9.47uF cap for the midrange and a .92mH inductor for the woofer, nether of which is made. So, I went with a 10uF cap, this one here: Dayton DMPC-10 for the midrange, this one can also be used: Dayton PMPC-10 and a .90mH inductor, this one here: Jantzen 0.90mH 18 AWG Air Core Inductor for the woofer.

After waiting in suspense for them to get here, they arrived and I almost instantly got the crossovers out, but only redid one as I wanted to compare the two. Put the redone one in my left speaker and the right stayed original. Hooked them up to my recapped SX-1980 and put on a song that I had always noticed a lot of harshness with. Press play and listened to it through the right speaker, then switched to the left. No way, am I hearing what I think I am?! The harshness is all but gone, listening to the right speaker there is a blare and harshness, the left is sweet and unbelievably clear compared to the right, the treble and midrange in the left sounds tenfold better in clarity and definition compared to the right. The honk and blare of the woofer is all but gone as well. I am in shock, I never expected this much of a improvement. I going to be trying more songs to see how they sound, stay tuned!

Edit 9/25/17: The replacement I used for the .15uF cap come from Mouser, part number is 667-ECW-F2154JAQ.
 
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I have been listening to them ever since the last post, both now having the modded crossovers in and there is absolutely no doubt, they are a 100 times better. Vocals compared to before are near life like, the midrange and treble has a definition I never heard or came close to with the original crossovers, it's almost like listening to new speakers. They are still quite bright, I have both the tweeter and midrange dialed back to -2 and further dialing back would not be out of the question. But, the harshness and blare is gone. I am quite pleased with mod and would recommend it to anyone looking to tame the harshness of there speakers.
 
The current crossover points were about 1600Hz, down 6dB at 3200Hz for the woofer and a staggering 5300Hz, down 6dB at 2650Hz for the midrange

That part is confusing to me, can you reword it?

Congrats on making an improvement in an iconic speaker! You may have found what it takes for those to be 'loved'.

I never fiddled with my HPM40 crossovers, I just EWaved em to eliminate that tweeter, which I thought was the problem. Maybe it wasn't, huh?


I have a pair of 100s in storage, maybe I should do this....
 
What I meant is that it starts to crossover at 5300Hz for the midrange and 1600Hz for the woofer and the "down 6dB at 3200Hz" is the next octave, 3200Hz being the next octave up from 1600Hz and 2350Hz being the next one down from 5300Hz. Since it's a -6dB/octave crossover design for both the woofer and midrange, I was stating that the output was reduced by 6dB at that frequency since that was the next octave. Does that help?
 
Hey Matt, this will be an interesting thread for me to follow. After reading about everything I could relative to modifying HPM-100s, I decided to recap mine with the original values and put a graphic EQ in the chain. I've been satisfied with the results.

Did you by chance see this discussion? Lot's of interesting information and measurements from some of AK's best.

http://www.audiokarma.org/forums/showthread.php?t=211542
 
This is great news! I have some HPM-100's coming my way soon! Thanks for the info, don't be surprised if you get a pm from me asking a question or two :)

Cheers
 
Hey Matt, this will be an interesting thread for me to follow. After reading about everything I could relative to modifying HPM-100s, I decided to recap mine with the original values and put a graphic EQ in the chain. I've been satisfied with the results.

Did you by chance see this discussion? Lot's of interesting information and measurements from some of AK's best.

http://www.audiokarma.org/forums/showthread.php?t=211542
Being an owner, 100w versions, I'm interested as well. I can't say that mine are harsh, but my listening tastes may be different or the equipment I'm using may not bring that aspect out. Choosing between my AR3a and HPM-100, overall I prefer the HPM, but that is not a clear victory, just an overall impression.
 
pognoot said:
Did you by chance see this discussion? Lot's of interesting information and measurements from some of AK's best.

http://www.audiokarma.org/forums/sho...d.php?t=211542

No, I did not see that, thank you for pointing it out!

I have been more and more impressed by the mods I did. :yes::thmbsp: I just tried out some songs with female vocals (something that these speakers were never very good at before) and it was so changed that I thought for a second that the singer was in the room! I forgot to mention that the imaging also benefited greatly from the mods. Overall, if you want improve your HPM-100's, I would highly recommend trying this out, the difference it wrought in mine is astounding. It's easily accomplished and just as easy to rollback in case you do not like the change, though I cannot see why anyone wouldn't.
 
I dont see what the deal is here in changing the x-overs. Mine sound phenomenal as is !
I would like to think Mr. Bart Locanthi got it right from the beginning.

Im leaving mine stock.
 
Ok so I'm gonna ignore the slopes and 6 db down points cause there is nothing to change the slope in this first order crossover. It's a given and I get that.

Let me reiterate and correct me if i'm wrong, please.
The stock low pass of the woofer was at 1600 hz, and you moved it to 1200 hz by changing the .8 mH inductor to a .9 mH.

The stock high pass of the midrange was 5300 Hz and you moved it to 2400 Hz by changing the 4.7 uF cap to a 10 uF.

Correct?

Are you not worried about impacting the power handling of the midrange by lowering the crossover point almost an octave?

I am sure there are improvements that can be made to these crossovers. I would gladly mod mine. It's a good speaker but mostly due to a solid cabinet and drivers that are not junk. The crossover is very basic.

I've always preferred the 40/60 woofer except in the deep bass. And I've always believed that there was a fantastic speaker locked up in the HPM-100 waiting to get out.

Thanks for your thinking, testing and reporting!
 
Almost, the stock inductor is a .6mH and the stock cap is a 4.4uF, changed to a 4.3uF cap when I recapped them the first time as they do not make a 4.4uF cap. But other then those two things, you are correct sir. And no, I am not worried about the power handling, the cone has no more movement then before and if there is I cannot feel it. But, I would not go more then a 10uF cap, I figured that to be the max before it started playing frequencies that caused excessive cone movement, because the next size available is 12uF, and that would give a crossover point starting about 1900Hz, down 6dB at 950Hz, which is a little low considering how unmoving the cone is.
 
In reviewing schematics the HPM-60 u2 has a 6 uF cap to the midrange. Same midrange driver, smaller woofer (the 40 and 60 10" woofer).

Odd that Pioneer would have the mid go lower in that speaker vs the HPM-100. You would think that they would've crossed the mid over at a higher freq in the smaller woofer design, letting the woofer handle more of the midrange, not in the larger woofer design.

Lends credence to your findings!
 
Well, for the first time in my life my laziness has paid off big time!

I've been meaning to send matt my crossovers to work on , , , they
are still sitting here in the box and have never made it to the post office.

Now, I shall get them off and he can do the same mod on mine!!!

Hooray for lazy people!:banana:
 
In reviewing schematics the HPM-60 u2 has a 6 uF cap to the midrange. Same midrange driver, smaller woofer (the 40 and 60 10" woofer).

Odd that Pioneer would have the mid go lower in that speaker vs the HPM-100. You would think that they would've crossed the mid over at a higher freq in the smaller woofer design, letting the woofer handle more of the midrange, not in the larger woofer design.

Lends credence to your findings!
Just a guess, but possibly Locanthi felt that, in the case of the 60 (rated at 60w), that allowing the mid to take some of the higher frequencies off the woofer would permit the woofer to better perform in the lower registries. But as you stated, it does make for a good argument that the mid is capable of handling the lower frequencies at the rated 100w (again the 60 is only rated 60w), although the same may not be true where it relates to the 200w HPM-100. The 200w does have a different mid (part number), but no evidence to suggest that it's entirely a different mid.
 
:scratch2: Or... you modified the 100 crossover closer to the HPM-150 (which no one I'm aware of's ever complained about harshness) mid-tweeter crossover point (new=2400, 150=2600 Hz) , and lowered the mid to woofer lower, closer in the 150 crossover point too. The HPM-150 15.75" woofer to mid crosses at 750 Hz which makes sense, mid to tweeter 2600. From that I doubt you have to worry about power handling. 150s do just fine with those lower crossover points. If I was into it, 'd be tempted to lower the crossover to the super-tweeter too, make it a little more audible.
 
I am trying to find the thread where AK member Tripqzon reworked the xover to lower the woofer. I would be interested in comparing what he did to what Matt is suggesting. If I can find it I will post.
 
:scratch2: Or... you modified the 100 crossover closer to the HPM-150 (which no one I'm aware of's ever complained about harshness) mid-tweeter crossover point (new=2400, 150=2600 Hz) , and lowered the mid to woofer lower, closer in the 150 crossover point too. The HPM-150 15.75" woofer to mid crosses at 750 Hz which makes sense, mid to tweeter 2600. From that I doubt you have to worry about power handling. 150s do just fine with those lower crossover points. If I was into it, 'd be tempted to lower the crossover to the super-tweeter too, make it a little more audible.
If only we had specs for the various drivers. There are so many flavors for the HPM speakers it isn't funny.
 
I sold the mids and tweets out of my HPM-150s. Quickly.
For the same 'sound' reasons that I EconoWaved my HPM-40s.
I put small Heils in my HPM-150s and am very happy with them.
And yet, they are gonna be EconoWave'd soon, too.

The best thing about HPMs is the woofers and the cabinets.
 
If only we had specs for the various drivers. There are so many flavors for the HPM speakers it isn't funny.
Differences in mid and tweeter drivers between 100 and 150 is cosmetic. HPM-100 10-721A mid and 40-711A tweeter flat gray finish, HPM-150 10-723A mid and 40-713A bright brushed finish. The varitions of the part number A, B, C etc were reliability and cost changes.
 
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