HPM-900 mids and tweeters in HPM-100/150

Hardy172cup

New Member
I recently purchased a set of mids and tweeters for a pair of HPM-900's to try as an upgrade I'm my HPM-100's but realised that the tweeter holes do not line up :( but fortunately the mids do.

I have just swapped the mids over wich to my ears is a notable improvement due to the carbon graphite cone meterial instead of paper.

Has anybody else had any experience with this upgrade? I'm thinking perhaps I could drill new holes in the cabs to make the tweeters fit but I'm still in two minds about this.

I also have a pair of HPM-150 speakers and the mids and tweeters match up better cosmetically with the 150's but HPM-150's are so rare here in the uk perhaps I should just keep them original, I don't want to devalue my speakers incase I ever get round to selling them. I will try the mids in the 150's next to see how they sound and If they are an improvement then they will probly stay there but its just a shame to have the tweeters sitting around not being used
 
I'm not familiar with the differences in size between the two tweeters, but it might be possible to fabricate and adapter ring which would screw to the original opening using flat head screws, and that also would then be made with the correct size and screw pattern for the new tweeters. Maybe 1/4" thick would probably do it. Painted the same or a contrasting color to the cabinet, they might look pretty good. They could be made from wood, aluminum or plastic, depending on your tools, and skills.
 
I saw it in a thread somewhere, some says mids and tweets from 900 makes an improvement for HPM-100, so why not for 150? Try it, and tell what u think!
I am using KEF B-110 as midrange in my 150s with good result. I also recapped them, replaced the L-pads with fixed resistors and added new terminals.
So good, am planning the same cure for my 1100s.
All reversible, in case I ever want to sell them.
 
Thanks, that's a great idea! One of my friends does woodwork so I could ask him to fabricate me an adapter for them, I could also get him to fabricate an adapter of the same thicknes for the mid range to so it sits at the same level as the tweeter, otherwise the tweeter would stick out further than the mid-range and that could have a negative effect on the sound.

Thank you for your suggestion.
 
The kef b-110's are an interesting suggestion, I have a couple of those driver lying around, I will have to experiment with the different driver combinations to see wich I think produces the better sound.
 
I have just swapped the mids over wich to my ears is a notable improvement due to the carbon graphite cone meterial instead of paper.
Been using HPM-900 poly-graphite mids in my HPM-150s for 30+ years. This made the overall midrange sound notably smoother to me and anyone else that heard them before and after.
 
I recently purchased a set of mids and tweeters for a pair of HPM-900's to try as an upgrade I'm my HPM-100's but realised that the tweeter holes do not line up :( but fortunately the mids do.
Odd that they don't match up. I have HPM-100 tweeters in my HPM-900s and the holes matched up exactly. (Also HPM-100 woofers in the '900s.)

attachment.php
 
Last edited:
Odd that they don't match up. I have HPM-100 tweeters in my HPM-900s and the holes matched up exactly. (Also HPM-100 woofers in the '900s.)

attachment.php

Wow that's is strange! I always thought the tweeters did match up but after I purchased the I read on a post on this site that the tweeters did not match up so I waited for them to arrive and attempted to install them to find that the holes holes did not match up and the diameter of the 900 tweeters ware a little smaller, there is about half an inch difference.

I know pioneer changed the part numbers on there drivers as time whent by such as the A, C and C veriants in the HPM 100 drivers, maybe they changed the 900 tweeters at some point?

My tweeter have the part number 45-717A.

Ps I have two sets of HPM-100's and 150's and the tweeters do not fit in any of them.
 
Wow that's is strange! I always thought the tweeters did match up but after I purchased the I read on a post on this site that the tweeters did not match up so I waited for them to arrive and attempted to install them to find that the holes holes did not match up and the diameter of the 900 tweeters ware a little smaller, there is about half an inch difference.

I know pioneer changed the part numbers on there drivers as time whent by such as the A, C and C veriants in the HPM 100 drivers, maybe they changed the 900 tweeters at some point?

My tweeter have the part number 45-717A.

Ps I have two sets of HPM-100's and 150's and the tweeters do not fit in any of them.
The A, B, C etc. were production changes for improvements or reliability. The size and mounting dimensions always maintained backwards compatibility. So I am not sure what you have!
 
Hmm this is odd? Can anyone confirm the part number of the tweeters from HPM-900's?

My tweeters and midrange speakers came from Germany so perhaps there are differences between the European and US versions?

The guy selling them was a collector of vintage hifi, he also had the super tweeters crossovers and HPM-900 badges for sale so I just assumed he had parted out a pair of HPM-900's

They are defiantly the carbon graphite type cones used in the later HPM series? I will have to research further to see if my tweeters are actually from HPM-900's or some other pioneer speaker that uses similar tweeters? :confused:
 
Hmm this is odd? Can anyone confirm the part number of the tweeters from HPM-900's?

My tweeters and midrange speakers came from Germany so perhaps there are differences between the European and US versions?

I have one here in my hand.. 45-717A-1, btw according to the date code "8036"manufactured the 36th week of 1980.
 
(Going to have to stop relying so much on memory...)

Apparently I did modify the screw holes way back then to put 100 tweets in my 900s.They ARE different flange and hole spacing. Sorry about the misleading info.


attachment.php
 

Attachments

  • Piohpm-150-900tweetrs.jpg
    Piohpm-150-900tweetrs.jpg
    39.6 KB · Views: 320
I have one here in my hand.. 45-717A-1, btw according to the date code "8036"manufactured the 36th week of 1980.

The numbers under the part number on my tweeter are as follows

7 8052

I'm assuming that places my tweeters manufacture in the 52nd week of 1980?

I notice your part number has a 1 at the end so they are obviously a different part, I wonder what speakers they are from if not HPM-900's?

I cannot imagine there being differences between european and US models but I'm not sure as I have never owned a pair of 900's.
 
Ahh! that explains everything. I thought for a moment i had the wrong tweeters.

Thank you for your information anyway, Looks like will have to make some modifications to get them to fit the cabs of the 100's and 150's.
 
I also use the mids from the HPM-900 in my 100's and agree they are a notable improvement.

The only upgrade replacement tweeter I have found that is a drop-in replacement is the Beryllium ribbon tweeters from the Pioneer S-710. And they do sound MUCH better than the stock tweeters. They are very hard to find though. But given my experience I'd say it would be worth the trouble to retrofit the 900 tweeters in there.

Drilling into the HPM-100 isn't so scary because they are not so horribly expensive. I did drill new holes in HPM-1100 to replace the tweeter in those with a different Pioneer beryllium ribbon, and while that scared me at first, it was WELL worth it. Those HPM paper cone tweeters just aren't that great and the later ribbon tweeters that Pioneer used are terrific.
 
I have spotted some s-710's on "that auction site" hear in England but they are a distance away, about an 8 hour round trip and the seller will not post so I may have to pass on those, they are currently at £10 with 1 bid and not long left before the end of the auction, if they sell for the current bid of £10 I will be kicking myself but I'm currently suffering from a medical condition and the prospect of being in the car all day long is very daunting.
 
Not as easy to relocate the screws on the 100-150s as they use T nuts from the backside of the front baffle board, and machine screws. The 900s use wood screws into the front board. I recall I filled the existing screw holes with hot glue and made new holes for mounting the 100 tweeters.
 
I use HPM-900 crossovers and midrange drivers in my HPM-100's and am very pleased with the results. Been using them like this for over a year now.
 
I use HPM-900 crossovers and midrange drivers in my HPM-100's and am very pleased with the results. Been using them like this for over a year now.

The guy I got the mids and tweeters from also had the crossovers and super tweeters up for sale, perhaps I should of purchased them all. I have heard a lot of people claiming they have had good results using the HPM-900 crossovers in their HPM-100's due to the high crossover point from woofer to mid range in the 100 crossovers.
 
Not as easy to relocate the screws on the 100-150s as they use T nuts from the backside of the front baffle board, and machine screws. The 900s use wood screws into the front board. I recall I filled the existing screw holes with hot glue and made new holes for mounting the 100 tweeters.

That is what I figured I would have to do to get the HPM-900 tweeters in the HPM-100 cabs, I will have to make some measurements but I'm hoping that the HPM-900 tweeters will be just large enough to cover the original screw holes.
 
Back
Top Bottom