As the title says, saw these on ebay and they reminded me of the old PMC 3-ways. Checked out the drivers online and thought they had potential to sound good, but now I have them I couldn't be more disappointed.
Anyway, the facts:
The drivers:
Tweeter: 27TG
Vifa D75MX
Vifa M25WP
Crossover: uses monacor inductors and wilmslow 'supersound' caps.
series denoted by (s), parallel by //, described in order form input:
tweeter: (s) 5.6uF Cap, (s) inductor, unknown value, (s) variable potentiometer.
Mid: (s) 0.81mH inductor, 25uF cap, // 4.7mH inductor, // 5.6uF cap, (s) 3.3Ohm R, // 10 Ohm R.
Bass: (s) 2.7mH inductor, // 60uF Caps (2*30 uF)
Cabinet: No stuffing, approx 30*40*90 cm, a few foam pads, no enclosures for mid or trebble.
Thoughts so far:
Why the hell is there...
an inductor on the tweeter?
a 2nd order elect. xo on the mid low pass but a 1st order on the tweeter high pass? (given the FR of the drivers would have thought this to be the other way round)
The sound:
One speaker seems to have lost the connection to the tweeter.
The other speaker sounds dull and lifeless. The bass is extraordinarily bad, I can only describe it as loose and floppy, mad worse by the face it seems to roll off quite steeply after 40Hz...
The plan:
Cabinet: Cut off the bass and install a transmission line for the bass speaker, seal the mid.
Check the drivers individually sound OK.
measure the caps to confirm values, but probably ditch all but the large bypass caps on the bass drivers, keep the coils if possible, replace resistors with better quality items of fixxed value, remover the series inductor from the tweeter
model the crossover in software and re-design...
Anyway, quite literally any and all feedback, ideas and suggestions would be more than welcome, as at the moment I like the drivers but feel the cabinet and crossover are both letting the team down!
Probably worth mentioning that despite the terrible cabinet finish, the build quality is good.
Anyway, the facts:
The drivers:
Tweeter: 27TG
Vifa D75MX
Vifa M25WP
Crossover: uses monacor inductors and wilmslow 'supersound' caps.
series denoted by (s), parallel by //, described in order form input:
tweeter: (s) 5.6uF Cap, (s) inductor, unknown value, (s) variable potentiometer.
Mid: (s) 0.81mH inductor, 25uF cap, // 4.7mH inductor, // 5.6uF cap, (s) 3.3Ohm R, // 10 Ohm R.
Bass: (s) 2.7mH inductor, // 60uF Caps (2*30 uF)
Cabinet: No stuffing, approx 30*40*90 cm, a few foam pads, no enclosures for mid or trebble.
Thoughts so far:
Why the hell is there...
an inductor on the tweeter?
a 2nd order elect. xo on the mid low pass but a 1st order on the tweeter high pass? (given the FR of the drivers would have thought this to be the other way round)
The sound:
One speaker seems to have lost the connection to the tweeter.
The other speaker sounds dull and lifeless. The bass is extraordinarily bad, I can only describe it as loose and floppy, mad worse by the face it seems to roll off quite steeply after 40Hz...
The plan:
Cabinet: Cut off the bass and install a transmission line for the bass speaker, seal the mid.
Check the drivers individually sound OK.
measure the caps to confirm values, but probably ditch all but the large bypass caps on the bass drivers, keep the coils if possible, replace resistors with better quality items of fixxed value, remover the series inductor from the tweeter
model the crossover in software and re-design...
Anyway, quite literally any and all feedback, ideas and suggestions would be more than welcome, as at the moment I like the drivers but feel the cabinet and crossover are both letting the team down!
Probably worth mentioning that despite the terrible cabinet finish, the build quality is good.
Attachments
Drawing out the schematic for the cross-over will help immensely.
Looking up the woofer, an out of production unit (The other two still in production) I think I was able to come up with the T/S parameters (Need confirmation).
Running the sim I got these results.
Fs 28,Qms 2.0, Qes 0.34, Qts, 0.29, Le 1.3, Re 5.8, BL 10.4, Vas 145L
EBP for a ported design.
48L, Fb 39.25 Hz., -3.04Db@44.69 Hz., 102X245mm port.
Retuned
125L, Fb 35 Hz., -3.06Db@32.53 Hz., 102X83mm port.
__________________________________________________Rick..........
Looking up the woofer, an out of production unit (The other two still in production) I think I was able to come up with the T/S parameters (Need confirmation).
Running the sim I got these results.
Fs 28,Qms 2.0, Qes 0.34, Qts, 0.29, Le 1.3, Re 5.8, BL 10.4, Vas 145L
EBP for a ported design.
48L, Fb 39.25 Hz., -3.04Db@44.69 Hz., 102X245mm port.
Retuned
125L, Fb 35 Hz., -3.06Db@32.53 Hz., 102X83mm port.
__________________________________________________Rick..........
Connect the drivers without crossover and listen to them
Bass on normal levels
Midrange on low level
Tweeter on even lower level (or protected by a large cap say 10-50 micro
Do they sound OK
Do the pairs sound the same?
The box seem to be less than 50 liter the Fs in box is then about 60 Hz with a Q of about 0.7
A very small coil could be used in series with the tweeter, but it looks like a ferrite core coil and that is plain wrong.
Bass on normal levels
Midrange on low level
Tweeter on even lower level (or protected by a large cap say 10-50 micro
Do they sound OK
Do the pairs sound the same?
The box seem to be less than 50 liter the Fs in box is then about 60 Hz with a Q of about 0.7
A very small coil could be used in series with the tweeter, but it looks like a ferrite core coil and that is plain wrong.
I sure hope it is in parallel
in any case, tweeter parallel coil is small, so still no need to use ferrite, no
and maybe change that variable tweeter att
Ok, that should say ferrite coil.
I've made a model of this in passive xo designer today, it's a bit crude but gets a better understanding of what's going on.
From a phase point of view the transfers all look good, but I have to say from FR it looks pretty bad... I need to measure the components to verify the values before I can proceed, and increase the accuracy of the FRD in the simulation.
I'll put up some pretty pictures in a while...
I've made a model of this in passive xo designer today, it's a bit crude but gets a better understanding of what's going on.
From a phase point of view the transfers all look good, but I have to say from FR it looks pretty bad... I need to measure the components to verify the values before I can proceed, and increase the accuracy of the FRD in the simulation.
I'll put up some pretty pictures in a while...
in the mean time, some questions:
- Does anybody have experience working with a 3" dome midrange? if so what tips would you give for its implementation?
-Any thoughts on the bass drivers? is the bass just sloppy cos they're mounted in a colossal hollow box?
(final transmission line questions on a different thread)
- Does anybody have experience working with a 3" dome midrange? if so what tips would you give for its implementation?
-Any thoughts on the bass drivers? is the bass just sloppy cos they're mounted in a colossal hollow box?
(final transmission line questions on a different thread)
to me they look like the vivace 87.
Go for more info to http://audiocomponents.nl/drawings/vifa/classicline/
Or e-mail them ; they are very helpfull !!
good luck , Leon.
Go for more info to http://audiocomponents.nl/drawings/vifa/classicline/
Or e-mail them ; they are very helpfull !!
good luck , Leon.
That woofer has plenty of bass in a sealed box if used in a small room based on my use but I think it needs to be crossed lower than the dome likes.
I would be inclined to rebuild the front panel anyway into mirror images with the mid and tweeter offset.
I have never had much luck with dome midrange drivers myself but I have heard marvelous implementations using that mid
I would be inclined to rebuild the front panel anyway into mirror images with the mid and tweeter offset.
I have never had much luck with dome midrange drivers myself but I have heard marvelous implementations using that mid
Definatelt not any if the above diy designs... went through all of them.
looks like a pretty standard wilmslow audio cabinet, but when I spoke to them today they said it wasn't a ki they've ever done. Not surprisingly, taking the inductor out of the tweeter circuit helped a lot, as did switching the polarity on the mids.
I
looks like a pretty standard wilmslow audio cabinet, but when I spoke to them today they said it wasn't a ki they've ever done. Not surprisingly, taking the inductor out of the tweeter circuit helped a lot, as did switching the polarity on the mids.
I
Hi,
The bass driver will go fine in a properly proportioned big vented
box, and wouldn't be that too shabby in a smaller sealed box.
A TL will be very big.
The mid needs a a rear sealed chamber.
Main area of contention is baffle step and integration to the
mid dome. One approach needs serious x/o components
to null the impedance peak of the mid-dome.
Any tweeter coil should be parallel.
I suspect muppet x/o calculator components.
rgds, sreten.
http://sites.google.com/site/undefinition/diy
(see if nothing else, the excellent FAQs)
http://techtalk.parts-express.com/showthread.php?t=219617
http://www.zaphaudio.com
http://www.zaphaudio.com/ZA5/
http://audio.claub.net/Simple Loudspeaker Design ver2.pdf
http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://web.archive.org/web/20090902124715/http://geocities.com/woove99/Spkrbldg/DesigningXO.htm
http://www.rjbaudio.com/
http://web.archive.org/web/20090902202231/http://geocities.com/woove99/Spkrbldg/
http://speakerdesignworks.com/
http://www.htguide.com/forum/showthread.php4?t=28655
http://www.deadwaxcafe.com/vzone/david/david.htm
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
http://www.humblehomemadehifi.com/download.html
http://www.quarter-wave.com/
http://www.frugal-horn.com/
http://www.linkwitzlab.com/
http://www.musicanddesign.com/
Great free SPICE Emulator : http://focus.ti.com/docs/toolsw/folders/print/tina-ti.html
The bass driver will go fine in a properly proportioned big vented
box, and wouldn't be that too shabby in a smaller sealed box.
A TL will be very big.
The mid needs a a rear sealed chamber.
Main area of contention is baffle step and integration to the
mid dome. One approach needs serious x/o components
to null the impedance peak of the mid-dome.
Any tweeter coil should be parallel.
I suspect muppet x/o calculator components.
rgds, sreten.
http://sites.google.com/site/undefinition/diy
(see if nothing else, the excellent FAQs)
http://techtalk.parts-express.com/showthread.php?t=219617
http://www.zaphaudio.com
http://www.zaphaudio.com/ZA5/
http://audio.claub.net/Simple Loudspeaker Design ver2.pdf
http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://web.archive.org/web/20090902124715/http://geocities.com/woove99/Spkrbldg/DesigningXO.htm
http://www.rjbaudio.com/
http://web.archive.org/web/20090902202231/http://geocities.com/woove99/Spkrbldg/
http://speakerdesignworks.com/
http://www.htguide.com/forum/showthread.php4?t=28655
http://www.deadwaxcafe.com/vzone/david/david.htm
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
http://www.humblehomemadehifi.com/download.html
http://www.quarter-wave.com/
http://www.frugal-horn.com/
http://www.linkwitzlab.com/
http://www.musicanddesign.com/
Great free SPICE Emulator : http://focus.ti.com/docs/toolsw/folders/print/tina-ti.html
Last edited:
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