Illusus said:
Pictures (of a newer pair), impedance plats & partial T/S parameters here. i've got to get some test boxes (or new batteries for my precision scales) so i can generate Vas & the rest that fall out.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4550951648
dave
description of drivers and preliminary results
In reply to Planet10 who asked for pictures of drivers :
sorry no camera, so no pictures but here are some descritions. The parameters are my own measurements :
Driver 1 : Shaker brand 6 x 9 oval, threa way. The "midrange" if I can call it that is a PM speaker about 1.5 inches dia, and the "tweeter" is about 1". I cant see any kind of crossover capacitor. Qts = 2, Fs = 71, Vas = 19 L. ( is Vas relevant if I am not using a box ? ) Labeled "500 peak power" yeah, right.
Driver 2 : Taken from Sears silvertone console stereo. 8 inch, stamped frame, approx 1" diameter alnico magnet. Qts = 1.8, Fs = 86, Vas = 39 L. It has part numbers E6295 and DGL8 stamped on it. The cone is tapered, not a straight sided cone. Paper surround part of cone.
Driver 3 : bought off Ebay. 10 inch, stamped frame, and the magnet is less than an inch long, and is covered over with a thin metal shield, I am guessing this is magnetic shielding, maybe they came from an old TV. The magnet looks way too small for the speaker. Part number 19-100006 stamped on it. I think it may be an RSC speaker. Stamped basket, which is not cone shaped, it looks more like a flat bottomed bowl. It looks unusual to me, but then I am no expert. Qts = 3.4, Fs = 112, Vas = 19L. After I received this driver I thought to myself "why did I go and buy this stupid looking thing ... " so I have just left it sitting around for a couple of years.
So with all the suggestions here, over the weekend I got to work and built up some frames with bits and pieces available. Driver 1 onto a 48" x 9" x 1/2" mdf sheet, driver 2 onto a 24" x 9" x 1/2", and driver 3 onto a 36" x 14" x 1/2" sheet. This is just what I had lying around, nothing special about choice of sizes except obviously the 10" speaker needed the wider sheet. My ultimate idea is to use 48" high sheets, since I can then use standard 4' x 2' mdf sheets with minimum of cutting. So the frames I made are all 4' high, the shorter sheets I centered within the 4 feet of hight.
I then used cardboard taped on in various arrangements of wings and tops and bottoms and so on, both flat ie parallel to the from and ant angles.
The results. Driver 1, the 3 way, just did not sound any where near as good as the other 2. This surprised me, since I had been using it as a general purpose speake on my work bench, with no baffle at all, and it did not sound too horrible. But side by side with the other 2 it just sounded dull.
Driver # 2, the 8", sounded pretty good, certainly worth continuing with.
But Driver # 3, the 10 ", with the teeny weeny magnet, and the FS of 112 sounded great ! Even with no additional cardboard, the bass was not too bad. I dont like a whole lot of base anyway. I really thought this speaker looked crappy, but you cant tell by looking, can you. It had the highest Q of the 3 drivers, so perhaps that is why it is best ?
The other thing I found out was that all the fooling around with cardboard did not seem to make much difference. Certainly not additional top or bottom pieces. Maybe side pieces made a slight difference to the bass. I have to belive that side pieces MUST make a difference, since the panel is so narrow with out them, surely rear sound is getting to the front ??
So, this week I will forget about cardboard, and screw on some hinges and use solid mdf "wings" and see what effect they have.
In reply to Planet10 who asked for pictures of drivers :
sorry no camera, so no pictures but here are some descritions. The parameters are my own measurements :
Driver 1 : Shaker brand 6 x 9 oval, threa way. The "midrange" if I can call it that is a PM speaker about 1.5 inches dia, and the "tweeter" is about 1". I cant see any kind of crossover capacitor. Qts = 2, Fs = 71, Vas = 19 L. ( is Vas relevant if I am not using a box ? ) Labeled "500 peak power" yeah, right.
Driver 2 : Taken from Sears silvertone console stereo. 8 inch, stamped frame, approx 1" diameter alnico magnet. Qts = 1.8, Fs = 86, Vas = 39 L. It has part numbers E6295 and DGL8 stamped on it. The cone is tapered, not a straight sided cone. Paper surround part of cone.
Driver 3 : bought off Ebay. 10 inch, stamped frame, and the magnet is less than an inch long, and is covered over with a thin metal shield, I am guessing this is magnetic shielding, maybe they came from an old TV. The magnet looks way too small for the speaker. Part number 19-100006 stamped on it. I think it may be an RSC speaker. Stamped basket, which is not cone shaped, it looks more like a flat bottomed bowl. It looks unusual to me, but then I am no expert. Qts = 3.4, Fs = 112, Vas = 19L. After I received this driver I thought to myself "why did I go and buy this stupid looking thing ... " so I have just left it sitting around for a couple of years.
So with all the suggestions here, over the weekend I got to work and built up some frames with bits and pieces available. Driver 1 onto a 48" x 9" x 1/2" mdf sheet, driver 2 onto a 24" x 9" x 1/2", and driver 3 onto a 36" x 14" x 1/2" sheet. This is just what I had lying around, nothing special about choice of sizes except obviously the 10" speaker needed the wider sheet. My ultimate idea is to use 48" high sheets, since I can then use standard 4' x 2' mdf sheets with minimum of cutting. So the frames I made are all 4' high, the shorter sheets I centered within the 4 feet of hight.
I then used cardboard taped on in various arrangements of wings and tops and bottoms and so on, both flat ie parallel to the from and ant angles.
The results. Driver 1, the 3 way, just did not sound any where near as good as the other 2. This surprised me, since I had been using it as a general purpose speake on my work bench, with no baffle at all, and it did not sound too horrible. But side by side with the other 2 it just sounded dull.
Driver # 2, the 8", sounded pretty good, certainly worth continuing with.
But Driver # 3, the 10 ", with the teeny weeny magnet, and the FS of 112 sounded great ! Even with no additional cardboard, the bass was not too bad. I dont like a whole lot of base anyway. I really thought this speaker looked crappy, but you cant tell by looking, can you. It had the highest Q of the 3 drivers, so perhaps that is why it is best ?
The other thing I found out was that all the fooling around with cardboard did not seem to make much difference. Certainly not additional top or bottom pieces. Maybe side pieces made a slight difference to the bass. I have to belive that side pieces MUST make a difference, since the panel is so narrow with out them, surely rear sound is getting to the front ??
So, this week I will forget about cardboard, and screw on some hinges and use solid mdf "wings" and see what effect they have.
No tricks, if in the mood, I can be insanely patient. I pry up the plastic very very slowly, if it's slowly enough just a thin top layer of the foam(just on the glued edge) lifts up with the grill. If the foam lifts off the basket I seperate it with a scalpel. I usually use them in guitar cabs, sometimes I leave the grills on for that application.
I found them to sound very...interesting...with the cone inverted, I used a diy cardboard tube, stiffened with resin to connect the cone to the VC. If you recall, I mentioned(on the old fullrange forum) cutting and gluing a few of them together to make a 5x16 multicoil driver. That was fun, made everything sound dark, warm and wet...sort of eerie, fell apart eventually.
hmm, while typing this post, I came up with something neat to make out of these. Later.
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