I just picked up 4 of these dual woofer 3 way speakers. They were probably custom built in the 1970, they big and heavy. I've have been fixing the crossovers that fell apart over time.
The midrange and tweeters appear to be good quality and are mounted on top with speaker cloth covering the front and sides. The rear ported cabinets are approximal 3.3 cf with 2 10" woofers that I guess are Eminence. The internals have some unique braces and a quasi labyrinth design.
Any suggestions on how to get a better response curve?
The midrange and tweeters appear to be good quality and are mounted on top with speaker cloth covering the front and sides. The rear ported cabinets are approximal 3.3 cf with 2 10" woofers that I guess are Eminence. The internals have some unique braces and a quasi labyrinth design.
Any suggestions on how to get a better response curve?
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maybe a notch at 2.5khz......
That crossover is a hoot !!!!!!!!!!!!!!!
And I like the (felt ?) in the box surrounding the tweeter.....
Maybe another notch 400-800hz.
Otherwise, I like it.
Maybe it is a 2-way.
That crossover is a hoot !!!!!!!!!!!!!!!
And I like the (felt ?) in the box surrounding the tweeter.....
Maybe another notch 400-800hz.
Otherwise, I like it.
Maybe it is a 2-way.
There are some things that can be tried.
It looks like the Mid is mounted horizontally to the side of the tweeter, and also higher up.
And that they both are 15-20 cm back from the flat top enclosure edge?
Also the tweeter is offset forward of the mid quite a bit.
Without altering anything physically, and without more info.
That 2-3,5k 5-6 db peak might be quite noticeable, high likelyhood of being diffraction related.
Foam or felt on the top of the enclosure, from the top panel up to the tweeter.
Something covering that mounting " beam thing" going from the mid forward to the tweeter.
Foam covering below the mid, maybe some behind on the bare surfaces.
Can also try a combo with felt on the surfaces and foam pieces.
Some more acoustical resistance in front of the drivers would also knock more of the top octave a little down.
You can read up on it with searching on here.
As long as you have the capability of measuring.
And look other places like:
https://audioxpress.com/article/Diffraction-Doesn-t-Have-to-Be-a-Problem
For a transformation, a top baffle / enclosure for the mid / tweeter in a vertical configuration is a better solution in just about any case.
But also requires you to rebuild, make a new xo, invest time/money etc.
Looks ported, if the bass tuning is responsible for some of the 40-90 hz peak, it can be altered by changing the ports.
Something more then a basic frequency response measurement might be needed for better advice.
Driver parameters?
Enclosure parameters/dimensions and port?
Measurements of impedance?
Measurements of the individual drivers, summed , port etc?
Off axis measurements to some degree at least?
That would make it easier for someone to assist.
It looks like the Mid is mounted horizontally to the side of the tweeter, and also higher up.
And that they both are 15-20 cm back from the flat top enclosure edge?
Also the tweeter is offset forward of the mid quite a bit.
Without altering anything physically, and without more info.
That 2-3,5k 5-6 db peak might be quite noticeable, high likelyhood of being diffraction related.
Foam or felt on the top of the enclosure, from the top panel up to the tweeter.
Something covering that mounting " beam thing" going from the mid forward to the tweeter.
Foam covering below the mid, maybe some behind on the bare surfaces.
Can also try a combo with felt on the surfaces and foam pieces.
Some more acoustical resistance in front of the drivers would also knock more of the top octave a little down.
You can read up on it with searching on here.
As long as you have the capability of measuring.
And look other places like:
https://audioxpress.com/article/Diffraction-Doesn-t-Have-to-Be-a-Problem
For a transformation, a top baffle / enclosure for the mid / tweeter in a vertical configuration is a better solution in just about any case.
But also requires you to rebuild, make a new xo, invest time/money etc.
Looks ported, if the bass tuning is responsible for some of the 40-90 hz peak, it can be altered by changing the ports.
Something more then a basic frequency response measurement might be needed for better advice.
Driver parameters?
Enclosure parameters/dimensions and port?
Measurements of impedance?
Measurements of the individual drivers, summed , port etc?
Off axis measurements to some degree at least?
That would make it easier for someone to assist.
The tweeter offset is crazy! There might be a lot going on there delay and reflection wise.
Coil explosions happen around pre-pubescent boys. I had an 11yo boy unwind one of my Strat pickups. 🤬
Coil explosions happen around pre-pubescent boys. I had an 11yo boy unwind one of my Strat pickups. 🤬
well, for integration, running a cat378 (morel horn loaded dome) with a wide open eminence b102, the tweeter was maybe 2" set back from the front of the woofer.
I'd thought that on a 6db crossover, the cap on the tweet seems to move the tweet forward, while an inductor on the woof seems to move the driver backwards, which would require more offset than simply lining up the drivers' centers......
I'd thought that on a 6db crossover, the cap on the tweet seems to move the tweet forward, while an inductor on the woof seems to move the driver backwards, which would require more offset than simply lining up the drivers' centers......
Maybe stuff the port? I like a little smiley-face as much as the next guy, but that's 10 dB from 300 to 65. Depending maybe on how you took measurements.
Hi,
The design looks really strange. How does it sound, overall ?
I think the first step is to measure all drivers, also for distortion and buzzing noises from age etc.
Then bring cross overs to spec. However fr. response is not that bad for such an old speaker.
Perhaps one of solutions is to use DSP to equalize fr. response, then check if that really improves the result sonically.
It's not always so that frequency response measured on axis is decisive, and is not clear what designers of this interesting collection of chambers have had in mind.
Regards
The design looks really strange. How does it sound, overall ?
I think the first step is to measure all drivers, also for distortion and buzzing noises from age etc.
Then bring cross overs to spec. However fr. response is not that bad for such an old speaker.
Perhaps one of solutions is to use DSP to equalize fr. response, then check if that really improves the result sonically.
It's not always so that frequency response measured on axis is decisive, and is not clear what designers of this interesting collection of chambers have had in mind.
Regards
Thanks for all the responses.
The photos show how dusty the mid and tweeter areas are. That dust must be an accumulation of 50 years. I bought it from an estate and the house had orange shag carpet. Flash back to my parents house!
I bought 2 ten inch woofers after receiving advice from Simply Speakers. They are 4 Ohm rating that I wired in series so they should be 8 Ohm now. I ran the REW frequency test and not much difference below 300Hz. There is a L-Pad for the tweeter and I made some test with that. If I turn it down, the peak at 2000Hz flattens out significantly. But what is bugging me is the 10 db peak in the bass area. Below is the REW frequency response with the new woofers installed yesterday. Maybe I'll try plugging the 2 back ports and stuff the cabinet. The top 3 curves were at 3 different L-Pad settings. I can tweak it to make the 2000Hz peak less a problem. I'll try laying down some padding round the mid and tweeter to reduce the defraction.
The bottom one is with the old Eminence woofers.
Also, I worked on cleaning up the crossover. I was able to wind the inductors, zip tie, and coat them with polyurethane so they never unwind again. I hot glued them to the backing board. I will try and draw a schematic but I have no clue what value the inductors are. I tried one of the off-the-shelf 3 way cross over but the REW results were similar.
The photos show how dusty the mid and tweeter areas are. That dust must be an accumulation of 50 years. I bought it from an estate and the house had orange shag carpet. Flash back to my parents house!
I bought 2 ten inch woofers after receiving advice from Simply Speakers. They are 4 Ohm rating that I wired in series so they should be 8 Ohm now. I ran the REW frequency test and not much difference below 300Hz. There is a L-Pad for the tweeter and I made some test with that. If I turn it down, the peak at 2000Hz flattens out significantly. But what is bugging me is the 10 db peak in the bass area. Below is the REW frequency response with the new woofers installed yesterday. Maybe I'll try plugging the 2 back ports and stuff the cabinet. The top 3 curves were at 3 different L-Pad settings. I can tweak it to make the 2000Hz peak less a problem. I'll try laying down some padding round the mid and tweeter to reduce the defraction.
The bottom one is with the old Eminence woofers.
Also, I worked on cleaning up the crossover. I was able to wind the inductors, zip tie, and coat them with polyurethane so they never unwind again. I hot glued them to the backing board. I will try and draw a schematic but I have no clue what value the inductors are. I tried one of the off-the-shelf 3 way cross over but the REW results were similar.
Attachments
I added padding around the midrange and tweeters (RED is with pads) to see if the sound reflection and there was some improvement between 300 Hz and 1100Hz.. The slight decrease in the 2100Hz area is the result of an L-Pad change. There also is some flattening of the upper midrange 3000-6000Hz area. So changing how the midrange and tweeters are located should help. I suspect the dip at 1800 Hz is a bad crossover design I'll have to figure out what needs to change.
The bass area is not what I like. I expected with 2 10" woofers and 3.3 cu ft ported cabinet would yield deeper and flatter base.
The bass area is not what I like. I expected with 2 10" woofers and 3.3 cu ft ported cabinet would yield deeper and flatter base.
The current cabinets has 2 round cardboard ports of approximately 2.5” wide by 15”. I haven’t measure them because they are covered by the diagonal internal panels. I suppose I could measure them somehow. How do I figure out how long they should be?
I ended up scrapping the original junk hand-made crossovers and bought inexpensive 3-way crossovers on Amazon. The crossover points are now 850Hz and 6000Hz. The mids are old Jensen L15LX and I was not able to find the specs. Same with the Peerless tweeters, so custom making crossovers would be guess work. I also relocated the mids/tweeters to be flush with the front of the cabinets to eliminate the deflections from the original locations. Below is the current frequency response. I also eliminated the L-Pad. They now actually sound pretty decent. The Eminence woofers are 8 Ohm wired to 4 Ohm. I tried different woofers, but there was not much difference, so I am staying with the old ones. My amp is a 200 w/c Conrad-Johnson so it can handle just about anything.
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Changed the dual woofers from parallel to series. Here is the impact. The small living room has a lot of reflective surfaces.
After extensive listening, I switched over the to the Parts-Express Dayton crossovers with 375/3000Hz points. The cheap Chinese crossovers from Amazon just sounded flat and were missing a lot detail I got back with the Dayton which cost 3 times more. Also, have been trying different tweeter and midrange mount designs that go on top of the cabinets. Found there was sound reflections when they were mounted in some positions. Still offset the tweeter back.
