Exceptional build quality, great punchy bass and extended highs that breathe! Mid Range is forward and crystal clear but does not upset the overal balance. These are better suited to Analouge amplifiers and I am using a Pioneer A 70 or my Pioneer A8. I love these things and they sound as good as I remember them to be when they were new. I paid $60.00 for these and it's by far the best $60.00 I have ever spent!!

No need to say how nice they are, but mine have a strange behaviour: the stereo image is better when I cross the cables !
I placed the speakers in the room calculating where they would have the less resonance, but when I move transversally in front of the speakers, there is a "hole".
I checked all the cables, including inside the speakers, but no doubt, the red cable is the red cable, but it sounds better when I connect the two speakers differently.
If someone has an explanation, I woulld be for sure interested to hear it.

very good spaker to listen rock and pop music at home even today. But it's not easy to find them as good conditions. my own hpm 100 is 35 years old and I'm very pleased from both of them.

These speakers are superior to many modern speakers costing hundreds of dollars (sometimes more than $1000)- The mid range rise in presence is to be expected and is present in all multi-driver speakers as a function of their properties in general. The crossover will "hide or reduce this" in some speakers- there are several modifications some quite simple that can be performed to give a flatter response but most ears will not perceive this. Remember sound quality is highly subjective good specs on paper will not necessarily mean good sound and vice-versa. Most people perceive these speakers as producing a very high quality sound stage only bested by the like of Klipsch La Scalsas or such.

This speaker, as setup by Pioneer, sounds really bad. It is harsh, really harsh. I was puzzled about all the positive reviews. Looked online and found very little information on modifications. It looks like the reviewers just like harsh sound.

I was on my own, I already bought this heavy oldies, so, I took them appart to see why it sounded so bad. To my complete surprise the problem is in the crossover. The mid-range capacitor of 4.4uF is wrong making a big void in the sound. I guess the harshness comes from a sort of spectral vacuum? The correct value is between 70 to 100uF. I did one speaker and did an A-B comparison to the other unmodified speaker. The result was dramatic the harshness is gone and the sound is a lot more detailed.

During all this, I tested the HPM super tweeter and found that it produces very little sound. It is hard to even get a measurement of its sound output using top of the line Neutric sound analyzing equipment. I guess it was a gimmick from pioneer just for marketing games. But, it does not matters because the cone tweeter works just fine and does not needs the HPM tweeter help.

I also tried changing the crossover components for newer ones and did not improved at all. Also removing the pots (level controls) do not improve on the sound.

Overall, a bad, harsh sounding speaker that can be transformed into a sweet sounding, full range speaker by just changing the 4.4uF cap to 75uF.

Carbon fiber, cast aluminum drivers. Absolutely rigid, dense enclosures. Extended bass response. Soaring highs. Bullet-proof longevity.

The stunned expressions on the faces of those to whom I demonstrate them.

Occasional harsh midrange...could be attributable to amp clipping.

I've owned these for over 20 years now. Back in the 70's I sold a pair (I was a dealer then) to a good friend who uses them still. Mine were purchased, sans woofers, for $40. I used a set of JBL woofers in them for 15 years until the internet allowed one to conveniently purchase vintage products. That said, I bid on at least 10 sets of OEM woofers before I won a pair at my price point ($67). Replacing the JBLs made a noticeable improvement in the sound. A previously great system became absolutely superb.

I often relate as to how, if I could have any speaker system for less than a thousand bucks...well, I already have them.

I'm a live sound engineer, ex hifi salesman; and I've never heard speakers I'd trade for these...unless maybe someone has a spare pair of Klipshorns or Magnepans laying around.

Anybody?

Mine are a bit beat up looking and could use some veneer repair; but they sound just like 1977.

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Pioneer had a good thing going with these. They should still support--maybe even reissue--them. Alas, spares only available from cannabilized originals. Every spare part sold equals another great system gone.

Original price was around $700/pair...something like $2500 in todays money. Hardly anyone spends that kind of money on this stuff anymore.

Sigh....

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Most of them. I own several sets of speakers.

Quality of construction and components, sound stage an tone, Can play at high leverls.

Heavy, mid and treble can be considered "bright" ( correctable with crossover mod )

As most people know, the Pioneer company produced the HPM-100's in the late 70's to directly compete with the JBL L-100's.Whether or not they succeeded is debatable but, most people agree that the HPM-100's were well built and could produce ear-bleeding playback levels. Some complained that their sound was too "bright" and that they were fatiguing to listen to for any length of time. WELL.. I PARTIALLY AGREE BUT THERE'S A SOLUTION TO THAT (READ ON).

As to build quality, I can tell you that these speakers and their cabinets are top notch in construction and materials. The cabinets are very heavy and this is due to the thickness of the particle board used. Additional cabinet weight comes from the use of internal braces to keep the cabinet rigid. A separate chamber for the midrange is provided as well as lots of acoustical damping material. The woofer is a monstrous 12" unit with a massive and heavy magnet, and a CAST aluminum spider housing. This woofer is held in place by thick machine screws and nuts, not just self-tapping screws. Furthermore, there will be no woofer surround rot like the JBL-L-100's foam one, BECAUSE THERE IS NO FOAM SURROUND ON THE HPM-100's WOOFER!!. Instead, the 100's use a cloth surround impregnated with an oil based preservative that is flexible but does not rot.

The woofer cone is a graphite type material and is very rigid, making it impossible to flex during vigorous woofer excursions. In summarizing the woofer construction ….the analogy of a "built like a Sherman tank" comes to mind.

Not to be forgotten is the midrange, tweeter, and super tweeter. In the case of the midrange, it's almost like a "mini-woofer" in terms of having a heavy magnet and a flexible surround, in a rigid frame assembly. Did I mention that it's isolated from any woofer pressure waves, by being enclosed in its own isolation chamber?

The tweeter is pretty much a standard tweeter (not a dome or exotic shape), but once again its build quality is superb.

The super tweeter represents Pioneers attempt to counter high frequencies being directional by having a curved radiating surface. The crossover frequency for the super tweeter was supposedly 10K and therefore the super tweeter for the most part is not heard until the sizzle of Cymbals and other instruments capable of this range are played. Most listeners over 30 are not going to be able to hear these higher frequencies that well, but the mere fact that they're being produced adds a "presence" to that frequency range. I personally think that this design works well and gives the 100's a very good sound stage.

So what do I think of the sound of the HPM-100’s?

I’ve got mine placed flat on the ground eight feet apart with the end of a sofa almost (not quite) blocking the tweeter. Not the best placement or positioning.

For 30+ year old instruments of sound, and using late 1970's sound shaping EQ and crossovers , they sound very good, albeit a bit "bright" ( OK, there....I've said the "B" word ). The midrange is a bit overemphasized , but this was the norm in the late 1970’s ( and still is today ) as far as factory EQ design ) At high levels ( not normal ) they can be fatiguing , in my opinion, BUT ONLY AT HIGH LEVELS, due to this "brightness " in mid an treble ranges. The bass is strong, non-boomy, deep, and fairly accurate, with decent mid-bass reproduction. Despite my poor placement, I was initially dumb-struck by how “real “the sound stage was presented by the HPM-100’s. NO! they do not have the sound stage ( and the incredible price either! ) of B&W, Celestion’s, and other high end speakers, but let me tell you…, for 30+ year old speakers, they present a pleasing placement of musical instruments.

Now with the above said and done…,if.. one replaces the capacitors used in the crossover with new AUDIO GRADE capacitors, they become totally different speakers. No “brightness”, a sweeter, charming mid and treble, cleaner bass (which was NEVER that bad to start with) and just a noticeable overall improvement. Here is the parts list provided by poster dbFreak from AUDIOKARMA.org

Parts List - from Parts Express (for one pair of HPM-100's or two crossovers)

Qty Part Number Product
2 005-10 Mills 10 Ohm 12W Non-Inductive Resistor
2 027-419 Dayton DMPC-4.3 4.3uF 250V Polypr Cap
2 027-220 Dayton PMPC-3.0 3.0uF 250V Precis Cap
2 027-462 Jantzen 0.15uF 1200V Z-Superior Cap

An electric screwdriver helps in removing hold down screws

You access the crossover from the back (it’s where the. wire connects –screw out the entire unit) Once partially out, write down how the wires are connected.. Make sure you memorize how everything is mounted. ( hey! Take a picture beforehand with a digital camera). You’ll need to de-solder two sets of wires, the others pull off. After removing the entire crossover try to remove ( or cut) the binding contact glue that PIONEER used to anchor the original capacitors to the circuit board, then de-solder off originals and re-solder replacements.

I would also suggest that you reheat ALL solder joints, before putting crossover back into speaker cabinets. Degree of difficulty? 5 if you’ve got even the most basic of techno-geek skills, 7 if you think rosin is the name of a girl. OK…, that’s a techie joke.. LOOK IT UP ON GOOGLE!.

In closing , let me state that the HPM-100’s are to me the absolute best “bang for the buck” when you consider that they can be had for as little as $50.00 to as high as $300+ ( still cheap ) at garage sales, Craigslist ( where I got mine for $50.00 ) or eBay. Make EBay your LAST choice. Make sure that ALL the drivers (woofer, mid, tweeter, etc) are working and that the woofer has no rattling or pops when played semi to really loud. A HPM-100 that is working properly will just keep getting louder as you increase volume, if its good and you use a clean amplifier to test ( if this is possible ).

I kid you not, these speakers are gems. BUY THEM!

Very loud and impressive bas voices. Acustic control potans on the front.

None.

It's perfect and valuable speaker made by Pioneer. it's nearly imposibble to find an alternative speaker even today. You may very lucky If you have HPM 100 pairs. I have been using my own HPM 100's since 1978. By the time I compared several times My HPM 100 with JBL L 100, B&W DM series and JBL LX series ,
sony SS G 3 and G 5 but none of them satisfied me enough except HPM 100. I've 2 pairs of HPM 100 and 2 pairs of HPM 60 , SA-9800, SA-8800 Pionner amp. and SX-850 receiver.

The A-BOMB of Speakers. Or in modern terms the MOTHER OF ALL BOMBS. Period. No further discussion needed.

If you have to haul them around. I dropped one on my Pergo floor. The speaker sustained no damage. I can't say the same for my floor.

After buying a pair of HPM 100's and listening to them for a few weeks I figured out it might be a good idea to buy another pair to compliment what I already had. Man was I a genius!!! I bought these speakers back in 1977 and still have them today in 2008.From all the reviews I have read I can only add that if you are into hearing pure warm sound then these are the speakers to get. It seems that most of what we hear in our modern age sounds cold and plastic. Oh but of course because most of it is made of plastic. Go back in time to hear the epitomy of what music should sound like with what was and still is the very best sound of the time. The HPM 100'S will put you where you belong if you are an Audiophile. I have never had to replace a single piece on any one of these speakers. When cranking 200+ watts through them it becomes mind boggling. There is no distortion only loud pure music which as others have said can peel the paint off of walls.. The only complaint I get is from my wife who says the coffee table and floor vibrates too much upstairs. Such is life with high end components. If you own these speakers you know what I'm talking about. If you don't own them, then go out and buy a pair or more on EBAY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

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Never had them seviced in 31 years. I guess they were made to last.

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JBL L-100'S. Not even Close.

Lifetime of enjoyment
Great quality
Classic good looks

Weight and size. You'll need room for them, but they are so worth it!

I owned a pair of HPM-60's in high scholl (late seventies) and ran them with an SX-750. It was a great set up but I had always coveted the top of the line. Thanks to ebay I was able to realize my wish.

I have 4 HPM 100's and I am driving them with a SX-1250 receiver/amp. Pure heaven. These speakers and receiver are nearly 30 years old, and sound fantastic. Put the dial to 50% and I can almost peel the paint off the walls. Bowie and Pink Floyd are back. The woofers are have the coated edges so they will never rot. Super clean bass and excellent mids and highs. You would have to spend $5000.00 today to get equiptment this good.