For the past 27 years (or so, no one can really remember when we got the Infiniti's), my family has been passing around a pair of Infiniti Reference Threes for whomever needed a decent set of speakers. Now they've come back to me with the foam surrounds completely gone. Despite all the years, please don't assume I have any nostalgia for these things...I'm not a nostalgia kind of guy.
However.
After building a few pairs of speakers I need to confess that I am terrible at building cabinets. My dad was an electrical engineer, not a woodworker, and my strengths are in the same areas. Electronics, soldering, circuit design, etc. don't scare me one bit. Varnish? Sanding? Joints? No thank you.
That brings me back to the current situation. The sound of these speakers was never amazing, but the black cabinets still feel really solid. I'd like to re-use the cabinets and put in some modern drivers and crossover(s).
Here are the original specs:
Frequency Response: 47Hz - 25kHz
Crossover Frequency(ies): 400Hz and 3.5kHz
Sensitivity: 90dB (1 watt/1 meter)
Nominal Impedance: 6 ohms
Power Rating: 20 - 125 watts
Woofer: 8" (20.3cm) IMG
Midrange Driver: 5" (12.7cm) IMG
Tweeter: 1" polycell
The outer dimensions of the cabinets are:
Height: 21 5/8"
Width:10 1/2"
Depth: 9 1/2" (a little tough to measure, as the baffle is beveled)
Sealed cabinet.
I've always used kits and the cabinets they were designed for in my previous projects, so I'm not sure where to start with this one.
Basically, given this cabinet, what is a good pairing of drivers (1", 5", 8") and crossover design?
I was thinking of bi-amping the new speaker (I have plenty of amps that deliver lots of clean power) to make the replacement design easier. Most of the places I would use these I don't have a sub, so a setup that providers for a good bit of strength down low would be appreciated.
Thanks for any help (or suggestions that I just toss the things into the trash if that's the right answer).
However.
After building a few pairs of speakers I need to confess that I am terrible at building cabinets. My dad was an electrical engineer, not a woodworker, and my strengths are in the same areas. Electronics, soldering, circuit design, etc. don't scare me one bit. Varnish? Sanding? Joints? No thank you.
That brings me back to the current situation. The sound of these speakers was never amazing, but the black cabinets still feel really solid. I'd like to re-use the cabinets and put in some modern drivers and crossover(s).
Here are the original specs:
Frequency Response: 47Hz - 25kHz
Crossover Frequency(ies): 400Hz and 3.5kHz
Sensitivity: 90dB (1 watt/1 meter)
Nominal Impedance: 6 ohms
Power Rating: 20 - 125 watts
Woofer: 8" (20.3cm) IMG
Midrange Driver: 5" (12.7cm) IMG
Tweeter: 1" polycell
The outer dimensions of the cabinets are:
Height: 21 5/8"
Width:10 1/2"
Depth: 9 1/2" (a little tough to measure, as the baffle is beveled)
Sealed cabinet.
I've always used kits and the cabinets they were designed for in my previous projects, so I'm not sure where to start with this one.
Basically, given this cabinet, what is a good pairing of drivers (1", 5", 8") and crossover design?
I was thinking of bi-amping the new speaker (I have plenty of amps that deliver lots of clean power) to make the replacement design easier. Most of the places I would use these I don't have a sub, so a setup that providers for a good bit of strength down low would be appreciated.
Thanks for any help (or suggestions that I just toss the things into the trash if that's the right answer).
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Hi F&L, and how do you feel about repairing those shot foam surrounds, midrange too? I think a challenge of this kind is good for one's own intelect. If it were me, I'd certainly try that and then completely design a modern XO filter from scratch, reusing the coils and modifying these if necessary. I am a recycling kind of a DIYer. The potential for good SQ is there.
The procedure to start with would be first to make sure the units are electrically sound, voice coils measuring normal dc resistance values, and the tweeter not being stuck because of old ferrofluid, assuming it was there in the first place.
Have you got a service manual?
The procedure to start with would be first to make sure the units are electrically sound, voice coils measuring normal dc resistance values, and the tweeter not being stuck because of old ferrofluid, assuming it was there in the first place.
Have you got a service manual?
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No service manual. I'm inclined to put my refoaming skills in there with my cabinet making skills....weak. These were always OK, not great, so the effort to just restore that level of sound quality is not quite worth it in my mind. Playing the matching game with a design and components that are 30 years old seems like it would leave a lot on the table. I have to imagine drivers have improved a great deal in the last 3 decades.
I was just thinking, given that I need to get 3 drivers per speaker instead of 2, I should find some more money for this project. If there is a big improvement by spending more on a recommended driver hit me with it. That said, this isn't a thousand dollar project. Right now the speakers don't work, so any improvement over that would be good.
Dayton Audio RS range of drivers are very good value for the budget of yours, also Scan Speak Discovery Series, Peerless Nomex woofer and PPB midwoofer, Peerless fabric tweeters. SB Acoustics has alternatives and the list of brands goes on! Mini dsp and accompanying 6 channels of amps, measurement microphone will add to the costs. Maybe a hybrid solution, passive XO on mid and tweeter combo, mini dsp for woofer LP and MidTw HP.
Lojzek,
Thank you for all of the help and suggestions. I really appreciate your time. I think we are thinking along the same lines. I have a measurement microphone already, though my skills and experience in using it are limited so far. I was thinking a relatively simple tweeter and mid with their own crossover, then using a minidsp to do the crossover to the woofer.
Is there some open source software (or something) I could use to start modeling out the driver combinations and seeing what might make sense?
I think I also need to take apart one of the speakers and see what the internal bracing looks like, etc. and get a good idea of the internal volume of the box.
Sure, there is free software and powerful too.
Jeff Bagby's Software Page
http://libinst.com/Xsim/XSimSetup.exe
FPGraphTracer : fprawn labs
Tolvan Data
I think that's all you might need, even more.
Jeff Bagby's Software Page
http://libinst.com/Xsim/XSimSetup.exe
FPGraphTracer : fprawn labs
Tolvan Data
I think that's all you might need, even more.
Probably you'll find extruded acethate ( pillows ! ) and 1" chipboard walls without any bracing. The speakers being without threading inserts, probably they'll need some
Oh ! And a "cup" behind the midrange driver.
Probably you'll find extruded acethate ( pillows ! ) and 1" chipboard walls without any bracing. The speakers being without threading inserts, probably they'll need some
Oh ! And a "cup" behind the midrange driver.
You nailed it! I finally got a chance to pull them apart today. Actually, it isn't as good as you said.
3/4" MDF, no bracing
pillow stuffing
cup behind midrange.
Not sure it is worth it to proceed having seeing the inside. Some cheap knock down cabinets from Parts Express would be better than these since they at least have internal bracing. Though, after a quick search, I didn't see ones as big as these...but that isn't necessarily an advantage.
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