an oval would be fine - - I'm not sure ihow much the speaker's orientation would matter - - it could allow somewhat different form factors.
it it fullrange? coax? woofer?
a "diamond" aperture for an oval on small open baffle.
http://audiokarma.org/forums/index.php?threads/open-baffle-epiphany.566879/page-52
I tried a cardboard double aperture (inverted aperture in the rear - like a very shallow "Kazba") K-slotted cardboard baffle with an oval Boss 6x9 $10 car speaker. That sounded good and better than direct radiator.
Karlson's klam models AP-W and AP9-C used a 6x9 oval - but that was the best fit
it it fullrange? coax? woofer?
a "diamond" aperture for an oval on small open baffle.
http://audiokarma.org/forums/index.php?threads/open-baffle-epiphany.566879/page-52
I tried a cardboard double aperture (inverted aperture in the rear - like a very shallow "Kazba") K-slotted cardboard baffle with an oval Boss 6x9 $10 car speaker. That sounded good and better than direct radiator.
Karlson's klam models AP-W and AP9-C used a 6x9 oval - but that was the best fit
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I had my 6x9 on a rough cardboard baffle kinda like below - think it was roughly 12" wide, 18-20" high and perhaps 3.5-4" deep. The rear aperture was "upside down" . I poked some holes in the baffle to "de-Q" resonance.
The cheap Boss 6x9 does not have a pretty response, but sounds pretty good plus handles power well without an enclosure. I could live with it.
the gap at the top wasn't proportionately this large - it didn't seem to hurt to have the wider part of the "wedge" at the bottom
get some cardboard and tape
what's sad is that sometimes stuff like this is more satisfying than a pretty wood
enclosure that didn't turn out well (acoustically)
The cheap Boss 6x9 does not have a pretty response, but sounds pretty good plus handles power well without an enclosure. I could live with it.
the gap at the top wasn't proportionately this large - it didn't seem to hurt to have the wider part of the "wedge" at the bottom
get some cardboard and tape
what's sad is that sometimes stuff like this is more satisfying than a pretty wood
enclosure that didn't turn out well (acoustically)
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I just added a pair of bofu-like GRS 8FR-8 to a purchase to get over the free shipping threshold. Somebody somewhere sometime said these might work well in a Karlson or variant. TS parameters below - I'm thinking they'll be good for a Karlsonator 8? Anyone have any thoughts? BTW, these drivers are $10 each through the end of the day.
Resonant Frequency (Fs)39 Hz
DC Resistance (Re)7.02 ohms
Voice Coil Inductance (Le)1.28 mH
Mechanical Q (Qms)2.94
Electromagnetic Q (Qes)0.46
Total Q (Qts)0.4
Compliance Equivalent Volume (Vas)2.26 ft.³ (64L)
Maximum Linear Excursion (Xmax)3 mm
Resonant Frequency (Fs)39 Hz
DC Resistance (Re)7.02 ohms
Voice Coil Inductance (Le)1.28 mH
Mechanical Q (Qms)2.94
Electromagnetic Q (Qes)0.46
Total Q (Qts)0.4
Compliance Equivalent Volume (Vas)2.26 ft.³ (64L)
Maximum Linear Excursion (Xmax)3 mm
early on with its reviews, one owner noted Qts 0.851 - I don't know if newer production exhibits stronger motor or not - there may be some more recent measurements within Diyaudio threads.
they're on sale "now" for $10
GRS 8FR-8 Full-Range 8" Speaker Pioneer Type B20FU20-51FW
they're on sale "now" for $10
GRS 8FR-8 Full-Range 8" Speaker Pioneer Type B20FU20-51FW
Amazon review: 2.0 out of 5 stars
Amazon.com: Customer reviews: GRS 8FR-8 Full-Range 8" Speaker Pioneer Type B20FU20-51FW
By Amazon Customer on December 1, 2015
Verified Purchase
if you want bang for your buck, do not buy these. they sound horrible and began to resemble a woopie cushion when i turned up the volume.
GM
* This data was exported from the Dayton Audio WT3 Woofer Tester
*
* Manufacturer: GRS
* Model: 8FR-8
* Piston Diameter = 165.1 mm
* f(s)= 63.25 Hz
* R(e)= 7.43 Ohms
* Z(max)= 49.80 Ohms
* Q(ms)= 5.702
* Q(es)= 1.000
* Q(ts)= 0.851
* V(as)= 32.170 liters (1.136 cubic feet)
* L(e)= 1.14 mH
* n(0)= 0.78 %
* SPL= 91.00 1W/1m
* M(ms)= 12.67 grams
* C(ms)= 0.50 mm/N
* BL= 6.12
Amazon.com: Customer reviews: GRS 8FR-8 Full-Range 8" Speaker Pioneer Type B20FU20-51FW
By Amazon Customer on December 1, 2015
Verified Purchase
if you want bang for your buck, do not buy these. they sound horrible and began to resemble a woopie cushion when i turned up the volume.
GM
* This data was exported from the Dayton Audio WT3 Woofer Tester
*
* Manufacturer: GRS
* Model: 8FR-8
* Piston Diameter = 165.1 mm
* f(s)= 63.25 Hz
* R(e)= 7.43 Ohms
* Z(max)= 49.80 Ohms
* Q(ms)= 5.702
* Q(es)= 1.000
* Q(ts)= 0.851
* V(as)= 32.170 liters (1.136 cubic feet)
* L(e)= 1.14 mH
* n(0)= 0.78 %
* SPL= 91.00 1W/1m
* M(ms)= 12.67 grams
* C(ms)= 0.50 mm/N
* BL= 6.12
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I think it is actually in this thread here: advantages of karlsonator
You recommend scaling the width of Karlsonator to 24" (outer dim, other dimesions identical?) for the lower bass extension or use the original K12. I was wondering if there was any real build. I would like to have a "flat pack" kit made, but need to choose the correct model
You recommend scaling the width of Karlsonator to 24" (outer dim, other dimesions identical?) for the lower bass extension or use the original K12. I was wondering if there was any real build. I would like to have a "flat pack" kit made, but need to choose the correct model
Beta12cx should work pretty well in the stock Karlsonator ("12")
I had Beta12CX (qts higher than spec) in K12 - think it was just a bit undersized.
- making a new K about X15's bulk with about 2 cubic foot rear chamber and one
cubic foot front could be interesting for Beta12CX. I once had Beta12CX in an X15 copy-
it didn't measure so well and probably needed to be built more like a regular K12 in shape,
but it startled me on a Japanese big drum hit - It played so loud that I thought the cone
would either break or jump out of the cabinet - but it only moved about 1/4" peak to peak.
A cabinet like that - if measured smooth and sounded free of artifacts, would make a nice
speaker to augment with a sub-woofer.
here's the way Beta 12lta did with mine - it reaches about
the same LF as K15.
I had Beta12CX (qts higher than spec) in K12 - think it was just a bit undersized.
- making a new K about X15's bulk with about 2 cubic foot rear chamber and one
cubic foot front could be interesting for Beta12CX. I once had Beta12CX in an X15 copy-
it didn't measure so well and probably needed to be built more like a regular K12 in shape,
but it startled me on a Japanese big drum hit - It played so loud that I thought the cone
would either break or jump out of the cabinet - but it only moved about 1/4" peak to peak.
A cabinet like that - if measured smooth and sounded free of artifacts, would make a nice
speaker to augment with a sub-woofer.
here's the way Beta 12lta did with mine - it reaches about
the same LF as K15.
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Here's about what I figure Beta12CX would do in 1 pi when mounted in the Acoustic Control 115BK cabinet. That might be interesting to do a cutout for 15" then use an adapter ring for the 12" speaker. Also a somewhat downwards scaled.
115BK would be only about 13.5" deep without the aperture inset and 16" deep if scaled for an 18 inch speaker
small signal tuning for 115BK IIRC measured around 53Hz. K12 measure around 63Hz, and the stock Karlsonator12, ~37Hz.
115BK would be only about 13.5" deep without the aperture inset and 16" deep if scaled for an 18 inch speaker
small signal tuning for 115BK IIRC measured around 53Hz. K12 measure around 63Hz, and the stock Karlsonator12, ~37Hz.
if K12 were scaled a bit from 16.75 W x 24.5H x 13.75D, say to external dimensions of 18 wide, 26.5 high x 15 deep, then it might be a better fit for Beta12cx. Stock K12 with a single vent rather than distributed slit vent might work pretty well too. The question - where is the best position for that vent ?
Today I finished the first bamboo cutting board open baffle with Sonido SFR200A (great Fostex 8" alternative) and I can stop using my old particle board MLTL with the Beta12CX. These boxes are not practical to move around, too big and heavy. I am almost decided to go for the widened Karslonator made out of plywood, with handles, rubber feet and some durable finish as I would use these outside in the summer as background music for barbecues.
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