Mirror Image a Pioneer HPM-100

[Jnevill]

You wouldn't by chance be a California native would you? I have a spare HPM100 cabinet, woodworking skills and time to spare right now, this would be an interesting project...

 

[janikphoto]

If you plan to find a trashed orphan to test it out on, go ahead! Otherwise, you're just ruining a collectible pair of speakers. You won't gain much from it, as I think the home series has a lot more going against it than just the mirror imagining. They are rock and roll speakers, not ultra-high end monitors.

For all the talk of why pioneer didn't do this from the factory, it's obvious. Just the added cost in trying to ship and track two separate items that need to stay together is reason enough. Pairing up speakers from a single pile of exact duplicates is so much less labor intensive. Even just the cost of printing new shipping boxes for the different left and right sides...

 

[I.R.Brainiac]

If you plan to find a trashed orphan to test it out on, go ahead! Otherwise, you're just ruining a collectible pair of speakers. You won't gain much from it, as I think the home series has a lot more going against it than just the mirror imagining. They are rock and roll speakers, not ultra-high end monitors.

For all the talk of why pioneer didn't do this from the factory, it's obvious. Just the added cost in trying to ship and track two separate items that need to stay together is reason enough. Pairing up speakers from a single pile of exact duplicates is so much less labor intensive. Even just the cost of printing new shipping boxes for the different left and right sides...

Sorry Janik,I have to disagree.

There is a lot to be gained.They are not that collectable.(Pioneer sold a bazillion of these things)If you have a pristine pair,I could see wanting to keep them original,but any old average pair could be improved in a number of ways.(the crossover could use work...and I dont mean using the one from the HPM-900,it needs even more work IMO)

As for tracking?...a big R or L sticker or stamp?
Lots of the better speaker companies manage it just fine.(Pioneer included)(half of my Pioneer speakers are mirrored and the other half will be )It just wasnt a priority to mirror image back then.

Now only cheap speakers are not mirrored.Those that cant be bothered to offset the drivers just line them up vertically in the center...but even that isnt ideal for edge diffraction.(edge diffraction is a big deal...more so than most speaker companies would like to admit)

So the world would have one less pair of original HPM-100s...I'm ok with that.

 

[Arkay]

Some very nice speakers are not mirror-imaged.

Neither of my most recent speakers additions, Yamaha NS-1000Xs and Infinity Gammas, are mirror imaged. Oh, wait a minute. Maybe they are? Kind of hard to tell, since all the drivers are in alignment along the centerline...

Seriously, for asymmetrical speakers, mirror imaging will always produce a better soundstage, at least theoretically and it seems also empirically. I'd suggest getting a scrap box to try it, and perhaps also go with the idea of another layer of baffle, complete with curved edges, glued down tightly to the original baffle. You'll probably have to do some cutting to the original baffle in any case. If you alter the interior volume of the box, adjust for that, perhaps by adding bracing that compensates for the volume removed (and thus "killing two birds with one stone"). Combined with a crossover upgrade, you should enjoy audibly improved sound.

Looking forward to reports of your results. I have a pair of beat-up HPM-100s I might do this with, if you think the results are really worth it. (More likely I'll eventually just sell them, but... )