How to disassemble Harman Kardon HK-12 omnis?
- Thread starter theprep
- Start date
Any chance you could post a pic of the speaker?
theprep
Member
HK12 owners manual, gives a limited exploded view of the units: https://www.manualslib.com/manual/279124/Harman-Kardon-Hk12.html#manual
Last edited:
swechsler
Frog Whisperer
Looks like a 3 pointed (i.e. triangular) screw head. Not sure what they're called, but I have several of those bits in my various small screwdriver sets. Shouldn't be difficult to find. To make sure, take the original photo and enlarge it as high as you can on your computer. The picture you have here is rather small.
Actually, after taking a second look, you might want to try again, see if you can get it in better focus. Do you have a decent camera you can use (I assume this one was taken with a phone)?
Actually, after taking a second look, you might want to try again, see if you can get it in better focus. Do you have a decent camera you can use (I assume this one was taken with a phone)?
Yeah, If it's not one of those triangular screws then it could be a brad nail. I assume either way they would set into those tabs that are show in the rough exploded view of the cabinet. If you are willing to possibly destroy that cloth you may find more clues. Maybe even how to remove the driver you are trying to replace. Shine a bright sight through the cloth and see if there are any fasteners that hold the driver in place.
theprep
Member
They look almost teardrop shaped, very odd. I started exploratory surgery with a drill bit, I'll need cobalt.
If you look close, pic 3 you can see the mount tabs. I can always thread for use with slightly larger Allen bolt sockets.
If you look close, pic 3 you can see the mount tabs. I can always thread for use with slightly larger Allen bolt sockets.
Attachments
swechsler
Frog Whisperer
Those aren't screws, they're pins. If you enlarge the second picture, you'll see there's a gap where a flat piece of steel was rolled into a pin. Not sure how to remove them, though. If you can get to them from the inside, possibly you can push them out with a thin metal rod (maybe the flat end of a drill bit?). Or maybe even push them in from the outside.
theprep
Member
you were right. Bought a nail punch set, used a small flat head to get the pins out. Not much to the 6.5 drivers at all, square thin magnet. Replacing with a set of these: https://www.parts-express.com/dayton-audio-ps180-8-6-1-2-point-source-full-range-neo-driver--295-344 or possibly https://www.parts-express.com/tang-band-w6-2144-6-1-2-paper-cone-full-range-driver-8-ohm--264-959. Still researching what will work best for this application.
The audio tech called me yesterday, he recapped the amp/tuner, replaced tuning wire, cleaned and lubricated the pots. He gave the BSR sourced turntable a clean bill of health after servicing, he's attempting to replace the 10 belts/rubber associated with the tape deck if he can source the parts. Should be a decent system for what is when complete. I really hate USPS cracked the dust cover for the turntable, the entire system is complete and in good shape, minus that mishap.
Last edited:
I'd refoam the original drivers, if only to hear what they were meant to sound like. Sticking random drivers, no matter how excellent the driver itself, into a cabinet meant for another driver is not a recipe for success, so your noting that you are going to calculate the internal volume after you have settled on speaker choices isn't confidence building. And it sounds like the speakers were part of a system, which may have been designed with those drivers in mind for the amp.
At least you are getting advice from Madisound, who know what they are doing.
At least you are getting advice from Madisound, who know what they are doing.
theprep
Member
To address the above advice/input, yes I reached out to Madisound for expert advice. As stated, I was researching further which landed me at Madisound. My previous research indicates the stock speakers sound nasty, as the unit was more of an aesthetic design rather than performer. Though the HK series did have some higher end models, the HK12 was entry level and a part of the Slimline. With the amp mods and refurbishment, performance will be better than when it left the factory I'm confident.
Calculated .44cft volume, we're leaning towards the SEAS or Markaudio, ported. It's removeable fiberglass, possibly Kapok as suggested, insulation. The enclosure is molded/rotoform plastic, rather thick. I originally intended on replacing the drivers with something a tad better than stock, sell the unit, but decided to go a bit further since having the unit recapped/modified. Adam at Madisound will help me decide on the driver with the volume numbers, we'll tune the port accordingly.
I have enough material on the bottom to add a port rather cleanly. Should be a neat project to learn on. Excited to hear the results.
Calculated .44cft volume, we're leaning towards the SEAS or Markaudio, ported. It's removeable fiberglass, possibly Kapok as suggested, insulation. The enclosure is molded/rotoform plastic, rather thick. I originally intended on replacing the drivers with something a tad better than stock, sell the unit, but decided to go a bit further since having the unit recapped/modified. Adam at Madisound will help me decide on the driver with the volume numbers, we'll tune the port accordingly.
I have enough material on the bottom to add a port rather cleanly. Should be a neat project to learn on. Excited to hear the results.
Last edited:
That's great you're making the progress you've set out to make. Hopefully there will be lessons to learn. It would be very interesting to be able to find out who originally designed the HK-12. I know Stu Hegeman developed some speakers for HK. Before he did that, he worked with some pretty noteworthy names in the industry....
http://www.itishifi.com/2010/02/lowther-hegerman-teak-1950-1951-pair.html
I would be surprised if you have some Lowthers in your hands, but they might be worth having a second look at. At any rate. Greatest of luck with the speakers,
Please keep us posted
http://www.itishifi.com/2010/02/lowther-hegerman-teak-1950-1951-pair.html
I would be surprised if you have some Lowthers in your hands, but they might be worth having a second look at. At any rate. Greatest of luck with the speakers,
Please keep us posted
theprep
Member
Square ceramic magnets are not uncommon in audio drivers - EPIs used them. You are correct that those are not Lowthers, but are, instead something inexpensive, though, nonetheless, serviceable, possibly from CTS. They look rather like my memory of the driver in the somewhat similar Zenith Circle of Sound speaker, which is a pleasant, if limited speaker (and sounds much better than you would expect as an outdoor speaker).
I'll be curious what you think when you are done.
I'll be curious what you think when you are done.
theprep
Member
Heard back from Adam after providing my measurements. We're leaning towards the SEAS or Markaudio ported 2"x6". Of course I'll save the original speakers, refoam at some point.
"That’s good news.
The Seas H1794 (FEA18RCZ) 7" Full Range will work well in that volume sealed or ported. If you port it, you can get it to perform flat down to 60Hz. Even sealed the low end will be respectable."
I also like the Markaudio Alpair-10P Paper Cone 6" Full Range in there. Flat down to 63Hz. It will be ok sealed if you decide not to port
"That’s good news.
The Seas H1794 (FEA18RCZ) 7" Full Range will work well in that volume sealed or ported. If you port it, you can get it to perform flat down to 60Hz. Even sealed the low end will be respectable."
I also like the Markaudio Alpair-10P Paper Cone 6" Full Range in there. Flat down to 63Hz. It will be ok sealed if you decide not to port
David Pinneg
New Member
The Fostex FE166 will probably fit and they are good.
Best wishes
David P
Best wishes
David P
Similar threads
