know it s not "full-range" but might apply to some woofer helpers - FWIW I only had a small baffle ~24x36 inches to try a SN15C P-Audio for a quick run - bass was warm and adequate -- if anything it sounded a bit "thick" on some bowed bass viola and appeared to have more clean power than a BK20 which I don't think could play "car bass" tracks- Qts was about normal for bass reflex -- has anyone had the perception of usable bass from low-moderate q drivers with open baffle and no EQ? did anyone here mess with open baffle for 15" P-Audio coax?
SN15C woofer alone o baffle
heres what the coax's basket looks like - don't make fun of me for playing with coax - they were $70ea new
SN15C woofer alone o baffle
An externally hosted image should be here but it was not working when we last tested it.
heres what the coax's basket looks like - don't make fun of me for playing with coax - they were $70ea new
An externally hosted image should be here but it was not working when we last tested it.
Freddi, you have a museum of Karlsons. I like the coax idea and always think about getting a pair to play with.
I wanted to email you the other day but you don't accept emails...
email me at Godzilla3@hotmail.com
Godzilla
I wanted to email you the other day but you don't accept emails...
email me at Godzilla3@hotmail.com
Godzilla
my wardrobe
An externally hosted image should be here but it was not working when we last tested it.
Hi,
I'm using woofers of Qts=0.3 on OB and very satified with some EQ and most important - T-bass circuit.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=130679&perpage=25&pagenumber=3
Please don't turn down EQ. EQ's are everywhere, be it electrical or acousitcal, or even psychological.... Electrical EQ is not the most evil, and it works. So why not?
I'm using woofers of Qts=0.3 on OB and very satified with some EQ and most important - T-bass circuit.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=130679&perpage=25&pagenumber=3
Please don't turn down EQ. EQ's are everywhere, be it electrical or acousitcal, or even psychological.... Electrical EQ is not the most evil, and it works. So why not?
hi - - regarding the T-bass circuit - is yours tuned to the driver/baffle fs so the input impedance isn't dragged down low? -- with simple C-L passive underdamped 2nd order highpass filters I've had one amp "ratchet" at very low spl levels due to the low Z load with vented systems and one 21" open baffle,
I'd like to see some input Z graphs for this circuit (or good simulation) - - seems like there would be no free lunch - but - there might almost be if its tuned to drive more voltage right into the Z peak region.
what transformer or autoformer are you using?
here's example of Z - a little K-coupler with aobut 2 cubic foot rear chamber loaded with JBL tuned in high 40's
with 500uF/20mH. Going up to 30mH made it a bit easier to drive but still touchy with a Samson F1200 amp.
No network
No free lunch network added
and some network effects on a baffle
I'd like to see some input Z graphs for this circuit (or good simulation) - - seems like there would be no free lunch - but - there might almost be if its tuned to drive more voltage right into the Z peak region.
what transformer or autoformer are you using?
here's example of Z - a little K-coupler with aobut 2 cubic foot rear chamber loaded with JBL tuned in high 40's
with 500uF/20mH. Going up to 30mH made it a bit easier to drive but still touchy with a Samson F1200 amp.
No network
An externally hosted image should be here but it was not working when we last tested it.
No free lunch network added
An externally hosted image should be here but it was not working when we last tested it.
and some network effects on a baffle
An externally hosted image should be here but it was not working when we last tested it.
and one more graph - too bad I don't have input Z for these - some amps can handle low Z loads - others can't
if amplifier source impedance is high then it won't work
An externally hosted image should be here but it was not working when we last tested it.
if amplifier source impedance is high then it won't work
An externally hosted image should be here but it was not working when we last tested it.
freddi said:
This is new to me! Wouldn't that inductor in parallel with woofer eat up much of the low frequencies? So, even though the system impedance is low here, much of the dirving current goes to inductor instead of woofer, doesn't it?
This is the impedance plot of my woofer (Eminence SigmaPro18) on baffle (120cm H x 90cm W):
And this is the same woofer on same baffle but with T-bass circuit:
T-bass circuit drags down the impedance big time! At some frequcies it approaches 1 Ohm. My tube amps previously used were unhappy with that. Luckily my old Halfer SS amp is doing fine.
-- cap's ireactance is offsetting some of the choke's falling inductance at LF - at some point there resonance - Cool graphs and WoW ! - that T-bass looks tuned nice but that load would likely elicit cracks and clicks from my wimpy Samson (I've got other solid state which might (?) drive it. This brings the question of active EQ vs trying to pull more current. I think the Erse choke I used got pretty saturated - it would pull pliers strong on drum beats and make them jump
what is the voltage and VA rating of your transformer? what are your woofer(s)? - this is fun stuff and I couldn't see well enough to follow that thread
what is the voltage and VA rating of your transformer? what are your woofer(s)? - this is fun stuff and I couldn't see well enough to follow that thread
I'm using 400VA toroid transformer and 4.2mH iron core inductor for each channel:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=130679&perpage=25&pagenumber=6
(I changed the caps later, but all irons remain the same... )
The woofer is Eminence Sigma Pro18. And this is the entire OB:
It's a very simple build and I'll redesign the baffle in the near future....
http://www.diyaudio.com/forums/showthread.php?s=&threadid=130679&perpage=25&pagenumber=6
(I changed the caps later, but all irons remain the same... )
The woofer is Eminence Sigma Pro18. And this is the entire OB:
It's a very simple build and I'll redesign the baffle in the near future....
cool baffles! - whats the size and offsets? what do you intend to change?
my apologies for missing the driver description text above your Z graph - - -
love your midrange size - are there more guitar speakers which are suitable? (10" Buddy are sometimes used). Are there stock drivers which are close to what Bastanis builds?
I've used 18 pretty close to Sigma in Karlson-type and they're durable - not much low bass but high impact and low cone excursion with 200-400W peak
was there much discussion of Graham's circuit price of low impedance tradeoff? ---using an autoformer like that would reflect a lower Z.
my apologies for missing the driver description text above your Z graph - - -
love your midrange size - are there more guitar speakers which are suitable? (10" Buddy are sometimes used). Are there stock drivers which are close to what Bastanis builds?
I've used 18 pretty close to Sigma in Karlson-type and they're durable - not much low bass but high impact and low cone excursion with 200-400W peak
was there much discussion of Graham's circuit price of low impedance tradeoff? ---using an autoformer like that would reflect a lower Z.
I tried to use AJ-Horn to simulate the C-L network - seems to take a bit of fudging with choke and cap resistance - this is for K33E woofer in 120 loiter box - IIRC Rudolf thought of a way to get H-baffle simulation in AJ -- looks like it could be used to get lower on open baffle - might take some adjustment to keep Z from dipping too low
btw - heres a little Karlson 12 copy with its regular port blocked and a smaller hole cut in the reflector with pym1298 and C-L "boost" - look how much 'louder" it was than my 21" Q=1/fs-30 open baffle - with 200 watts input the little Karlson could hit very hard - about like a Klipschorn - I think the Erse choke's saturation could be heard (?) the dip might be lessened with 25 degree baffle (i think) pym1298 won't go up high enough for a K-tub HF waveguide.
An externally hosted image should be here but it was not working when we last tested it.
btw - heres a little Karlson 12 copy with its regular port blocked and a smaller hole cut in the reflector with pym1298 and C-L "boost" - look how much 'louder" it was than my 21" Q=1/fs-30 open baffle - with 200 watts input the little Karlson could hit very hard - about like a Klipschorn - I think the Erse choke's saturation could be heard (?) the dip might be lessened with 25 degree baffle (i think) pym1298 won't go up high enough for a K-tub HF waveguide.
An externally hosted image should be here but it was not working when we last tested it.
and tried looking at sigma18 but don't know how to do baffles in AJ so just used 99999 liter - the amount of boost and Z dip look about ballpark (?) wonder if MJK's progam would get it more accurate? is ther freeware to do Graham's T-boost?
An externally hosted image should be here but it was not working when we last tested it.
Hi,
TBH I can't fully follow the simulations above😱 It seems the function of that high Q 2nd order LC filter is very similar to the T-bass circuit. However the T-bass circuit is not easy to simulate. I don't know any program can do it properly. (maybe some exist, but I don't know.... )
My baffle on the pictures above was originally designed for a single 8" fullranger (in a small room for very low SPL of course). It was put aside for a while. Then additional 2 holes were cut for the tweeter horn and woofer, it is now very flimsy and actually pulled backward by the woofer's magnet. I'm using a stick to help supporting it. When playing loud with bass rich materials, the baffle vibrates quite a lot.
I'm planning on building an H-baffle for woofer and a separate flat one for mid-high, then I can make isolation in some ways between them...
I've been very interested in your K-couplers. I bet they'd sound excellent. However in my own application now, any boxed speakers (of this size) are not suitable. I've used aperiodic boxes for the same Sigma Pro 18 before, and the bass flooded the room. Now my living room is even smaller, so I can't deal with that.
On the other hand, I found OB bass is easier to get right -- faster in reacting and cleaner. With this woofer, in room, I can get down to about 25Hz. 2 of them already overwhelm the room, with not much power and cone displacement, even by the OB loss. And I'll soon add another 2
Back to the K-coupler, is it possible to make it longer (taller) to get lower? I guess that'd be similar to a tapped horn but with a k-slot type of mouth.
TBH I can't fully follow the simulations above😱 It seems the function of that high Q 2nd order LC filter is very similar to the T-bass circuit. However the T-bass circuit is not easy to simulate. I don't know any program can do it properly. (maybe some exist, but I don't know.... )
My baffle on the pictures above was originally designed for a single 8" fullranger (in a small room for very low SPL of course). It was put aside for a while. Then additional 2 holes were cut for the tweeter horn and woofer, it is now very flimsy and actually pulled backward by the woofer's magnet. I'm using a stick to help supporting it. When playing loud with bass rich materials, the baffle vibrates quite a lot.
I'm planning on building an H-baffle for woofer and a separate flat one for mid-high, then I can make isolation in some ways between them...
I've been very interested in your K-couplers. I bet they'd sound excellent. However in my own application now, any boxed speakers (of this size) are not suitable. I've used aperiodic boxes for the same Sigma Pro 18 before, and the bass flooded the room. Now my living room is even smaller, so I can't deal with that.
On the other hand, I found OB bass is easier to get right -- faster in reacting and cleaner. With this woofer, in room, I can get down to about 25Hz. 2 of them already overwhelm the room, with not much power and cone displacement, even by the OB loss. And I'll soon add another 2
Back to the K-coupler, is it possible to make it longer (taller) to get lower? I guess that'd be similar to a tapped horn but with a k-slot type of mouth.
taller k-coupler may go lower but at some point I would think overall bulk of the front slotted pipe would rule == I had one 42" tall coupler and topped with a Unity horn it was quite a bit cleaner than a Silver Iris but not fair to compare..
it might be possible to arrange a tapped horn like a K but not sure how it would function or sound. Part of Karlson's stategy was to add mechanical reverberation. Baffle tilt, the opening at the top, and the internal panel above the baffle may affect brightness and focus/ Karlson oriiginals can sound pretty good with certain speakers -in particular fullrange -That may be partly due to me not being smart enough to make a good crossover.
some Karlson show two dips - that may not screw up the sound - Acoustic Control built a copy of Walter Zintz's little KHYBOE and that produces better midrange graphs but that coupler only had 2 cubic foot rear chamber so LF corner is around 80Hz half-space. Port position can affect tone.
I like open baffles too but not had one great yet so will have to try again and probably like you use a H-baffle for LF and flat wingless baffle for mid-HF. Somewhere in my pile I have Eminence Buddy and had Dayton waveguides. I briefly ran APT50 on Beta 12CX and APT80 or KSN1005 above 12LTA
- - Although the 21" woofer sounded ok on electronic music, it didn't sound great on bowed bass or cello - - - would a driverack help fix that problem?.
did you hear any vertical spatial shift with some music where the harmonics disassociate in position with the mid driver? (and perhaps the bass) I'm used to coax and for whatever limitations they have, thats' not one of them.
it might be possible to arrange a tapped horn like a K but not sure how it would function or sound. Part of Karlson's stategy was to add mechanical reverberation. Baffle tilt, the opening at the top, and the internal panel above the baffle may affect brightness and focus/ Karlson oriiginals can sound pretty good with certain speakers -in particular fullrange -That may be partly due to me not being smart enough to make a good crossover.
some Karlson show two dips - that may not screw up the sound - Acoustic Control built a copy of Walter Zintz's little KHYBOE and that produces better midrange graphs but that coupler only had 2 cubic foot rear chamber so LF corner is around 80Hz half-space. Port position can affect tone.
I like open baffles too but not had one great yet so will have to try again and probably like you use a H-baffle for LF and flat wingless baffle for mid-HF. Somewhere in my pile I have Eminence Buddy and had Dayton waveguides. I briefly ran APT50 on Beta 12CX and APT80 or KSN1005 above 12LTA
- - Although the 21" woofer sounded ok on electronic music, it didn't sound great on bowed bass or cello - - - would a driverack help fix that problem?.
did you hear any vertical spatial shift with some music where the harmonics disassociate in position with the mid driver? (and perhaps the bass) I'm used to coax and for whatever limitations they have, thats' not one of them.
freddi said:
I had used digital EQ and analog active xover to 'fix' the OB loss. It worked, to some extent. RTA shows pretty flat and extend pretty low, but the sound quality was not so satisfying.
Until I hooked on the T-bass circuit. It works really good with my 18"ers. It excels in all bass sounds, drums, electric or acoustic bass, bowed bass... you name it. Not sure about the 21" though.
freddi said:
Compared to coax (or fullrager), my 8" WG + 12" mid are not so 'focused' in imaging, that's surely audible. But "vertical spatial shift"? Oh that's a very strong description! I don't notice any, if it really exist. However I don't focus very much on the focus performance of speakers.
Anyway, with regard of imaging, now it's far better than my previous system with 30" mid horn -- that's much further apart from the tweeter.
I think where the situation of vertically spaced drivers exists, subjective image height and source position "may" change when a high pitched percussion instrument is played, so the sound source with the most output is some inches above the midrange unit - does this make sense? - or does a really good crossover summation prevent the illusion? for whatever faults a single driver or coax may have it should have less vertical shift(s)
how many dB boost do ou think the T-boost is accomplishing? does it do more than a C-L network other than reflect lower Z? (I need to look at its schematic)
that little magnet Goldwood 18 in MJK's project moving mass seems pretty light compared to the Madison 21" - both are 30Hz/Q~1 - it won't have the displacement of the Sigma but its midrange should be weaker. I got a lot of subjective power from Sigma type in a Karlson -- even outdoors - there wasn't any midrange gain - more a "mellowing" but cone excursion was low for the output.
how many dB boost do ou think the T-boost is accomplishing? does it do more than a C-L network other than reflect lower Z? (I need to look at its schematic)
that little magnet Goldwood 18 in MJK's project moving mass seems pretty light compared to the Madison 21" - both are 30Hz/Q~1 - it won't have the displacement of the Sigma but its midrange should be weaker. I got a lot of subjective power from Sigma type in a Karlson -- even outdoors - there wasn't any midrange gain - more a "mellowing" but cone excursion was low for the output.
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