I'm keeping it a secret from myself because I can not remember!It was cheap, it was well made, Parts Express sold them. Pretty sure they are discontinued.
I think it was the 15PW3-SLF based on this thread.
Can you help me understand this further.
I associate low Q with uncontrolled (sloppy) movement hence facilitating the big movement in low bass notes
If you select a high Q driver it will resist movement but surely you can ‘get this back’ by using a high power transistor amp.
Your "associations" for total Q (ts ) are in fact backwards.
This readily explains your choice of a woofer having the "wrong" Q for the job at hand.
Thanks EarlK, that's the one. I remember mine measuring higher Qts on baffle, maybe 0.7 or higher. On the baffle shown, it had nice, clean bass. At the time they were about $70 each, a little more than the Alpha 15 the cost. But worth it.
Somewhere on John Krevskovsky's website there is a paper showing that a Q of 1 is accurate bass. Anything below that is over-damped.
Somewhere on John Krevskovsky's website there is a paper showing that a Q of 1 is accurate bass. Anything below that is over-damped.
Sorry, schoolboy error. Lets try again.
Can you help me understand this further.
I associate high Q with uncontrolled (sloppy) movement hence facilitating the big movement in low bass notes
If you select a low Q driver it will resist movement but surely you can ‘get this back’ by using a high power transistor amp.
Can you help me understand this further.
I associate high Q with uncontrolled (sloppy) movement hence facilitating the big movement in low bass notes
If you select a low Q driver it will resist movement but surely you can ‘get this back’ by using a high power transistor amp.
I can't honestly say why throwing money at this problem ( of one's own creation that goes against "english common law" so to speak ) doesn't work as well as going by the advice of the trail-blazers who have lots of empirical experience in the matter.
I'll agree it's a bit of a paradox.
As an aside, 1980's era Meyer 650 Subwoofers did have an electronic circuit within their controller to address something like this question ( the circuit loosened up the subs response considerably by adding resonance & group-delay I'll assume > though I never scoped the processed signal to find out ).
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This is very basic so don't take it as the gospel.
Q is the driver's inability to come to rest after the signal has stopped. The higher the number, the more it will continue to vibrate after there is no signal. This adds a sense of warmth to the sound. Warmth is desirable in OB because you have a lot of wave cancellation without a box.
The sloppy of what you speak is more in the suspension ie: the surround and spider. Smaller motor drivers often have smaller spiders and restricted suspensions partly as a means of controlling that movement. Large motor drivers tend to move the cone fore and aft further and can change direction more quickly (good transient response). They are good at starting and stopping, hence the lower Q. Not good for OB because there is no warmth, they are the cold blooded killers of the audio world. They pound out the sound.
Q is the driver's inability to come to rest after the signal has stopped. The higher the number, the more it will continue to vibrate after there is no signal. This adds a sense of warmth to the sound. Warmth is desirable in OB because you have a lot of wave cancellation without a box.
The sloppy of what you speak is more in the suspension ie: the surround and spider. Smaller motor drivers often have smaller spiders and restricted suspensions partly as a means of controlling that movement. Large motor drivers tend to move the cone fore and aft further and can change direction more quickly (good transient response). They are good at starting and stopping, hence the lower Q. Not good for OB because there is no warmth, they are the cold blooded killers of the audio world. They pound out the sound.
Hi
Troels Graversen uses Ciare NDH 15-4 S for woofer on his OB, and he is very satisfied with the performance
But I would look for high Xmax ( at least +/-8 mm real Xmax), low fs and forget about the Qts of the driver. You are using DSP you can EQ your way out of Qts, and if you have DSP nothing beats large Xmax.
uwe
Troels Graversen uses Ciare NDH 15-4 S for woofer on his OB, and he is very satisfied with the performance
But I would look for high Xmax ( at least +/-8 mm real Xmax), low fs and forget about the Qts of the driver. You are using DSP you can EQ your way out of Qts, and if you have DSP nothing beats large Xmax.
uwe
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This is very basic so don't take it as the gospel.
Q is the driver's inability to come to rest after the signal has stopped. The higher the number, the more it will continue to vibrate after there is no signal. This adds a sense of warmth to the sound. Warmth is desirable in OB because you have a lot of wave cancellation without a box.
The sloppy of what you speak is more in the suspension ie: the surround and spider. Smaller motor drivers often have smaller spiders and restricted suspensions partly as a means of controlling that movement. Large motor drivers tend to move the cone fore and aft further and can change direction more quickly (good transient response). They are good at starting and stopping, hence the lower Q. Not good for OB because there is no warmth, they are the cold blooded killers of the audio world. They pound out the sound.
I like this explanation.👍
Another important thing is that you need to have really heavy baffles.
There is no air spring that restricts the membrane from moving back and forth to follow the music.
If the membrane moves forward fast, the baffle will have to move back.
The larger the difference betwwen the mass of the membrane and the baffle it is attached to the better. Isnt there a rule of thumb for that for boxed speakers?
There is no air spring that restricts the membrane from moving back and forth to follow the music.
If the membrane moves forward fast, the baffle will have to move back.
The larger the difference betwwen the mass of the membrane and the baffle it is attached to the better. Isnt there a rule of thumb for that for boxed speakers?
GM
The dumbells increase the weigth of the speaker / betters the ground connection and hence improves the impuls performance.
M(membrane) x V(membrane) = M(loudspeaker) x V(loudspeaker)
and those impulses are in opposite directions.
I now know that the baffles are not rigid enough. When I made them out off a 38 mm hardwood tabletop I had left over from a kitchen project
I thought it was overkill, but I became wiser.
Next project will be W-baffles/ dual ripoles for the woofers (force cancelation), minimum baffle for the midrange ( midrange fasternet only by the magnet and pushed against the baffle) and the Heil on top of it
Uwe
The dumbells increase the weigth of the speaker / betters the ground connection and hence improves the impuls performance.
M(membrane) x V(membrane) = M(loudspeaker) x V(loudspeaker)
and those impulses are in opposite directions.
I now know that the baffles are not rigid enough. When I made them out off a 38 mm hardwood tabletop I had left over from a kitchen project
I thought it was overkill, but I became wiser.
Next project will be W-baffles/ dual ripoles for the woofers (force cancelation), minimum baffle for the midrange ( midrange fasternet only by the magnet and pushed against the baffle) and the Heil on top of it
Uwe
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Hi Winnie,
you´ve asked for brand names and models, and I would suggest to have a look at the AE Dipole 15 or LO 15. They´re not cheap, especially not considering freight and taxes... but personally I never regretted my purchase of the Dipole 18 for my OBs. Regardless of what manufacturer says, they´ll need quite a bit of power.
Having seen your OB with the deep wings, out of the two 15 inch drivers I would choose the LO 15, the reason is the airload your design adds to driver performance, which lowers FS and Q.
I´m no friend of drivers with Qts higher than 0,7, that´s why I added a second magnet to my Dipole 18 (straight OB, no wings etc.) and brought the Qts from 0,84 to 0,66, then it was as good as it gets for my design (with a passive crossover), hence I would choose the LO 15 over the Dipole 15.
As you work with DSP an are going active, you have more choices, and the AE drivers are a good start.
I might also add that Uwe is right about OBs weight, as Cal is about stiffness. Both is important, and for a 15 inch driver, you should aim at 40 kg minimum, that´s from experience. I have the feeling that you´re not considering a rebuild of your OBs, but if so, you might want to think about decoupling the bass part of the OB from the rest.
All the best
Mattes
you´ve asked for brand names and models, and I would suggest to have a look at the AE Dipole 15 or LO 15. They´re not cheap, especially not considering freight and taxes... but personally I never regretted my purchase of the Dipole 18 for my OBs. Regardless of what manufacturer says, they´ll need quite a bit of power.
Having seen your OB with the deep wings, out of the two 15 inch drivers I would choose the LO 15, the reason is the airload your design adds to driver performance, which lowers FS and Q.
I´m no friend of drivers with Qts higher than 0,7, that´s why I added a second magnet to my Dipole 18 (straight OB, no wings etc.) and brought the Qts from 0,84 to 0,66, then it was as good as it gets for my design (with a passive crossover), hence I would choose the LO 15 over the Dipole 15.
As you work with DSP an are going active, you have more choices, and the AE drivers are a good start.
I might also add that Uwe is right about OBs weight, as Cal is about stiffness. Both is important, and for a 15 inch driver, you should aim at 40 kg minimum, that´s from experience. I have the feeling that you´re not considering a rebuild of your OBs, but if so, you might want to think about decoupling the bass part of the OB from the rest.
All the best
Mattes
let's refocus on the problem in our hand.
not enough bass (punch) with 416A on OB
i would check the vintage altecs to see if they are alright. best would be to have them measured for magnet power. vintage alnicos can lose magnet power and can also be recharged (i think). if you can't have them checked professionally, connect them directly to your amp and give them a listen individually and compare each against the other... also observe the cone move with bass heavy music.
i also recommend high passing your OB woofers with a steep filter on or just above their Fs to protect them for over-excursion.
your first OBs with saba+altec are very similar to lampizator's endorphin project:
Endorphine from Kingston Kitchen
he is very experienced and loves the saba altec combo....and i agree with him. so do not give up on your sabas and altecs yet.
with what you have in hand, you can always add some subwoofer(s) to have better deeper bass. if you are living in a flat, boxed subs can be difficult with neighbors. in that case you can try a separate ripole sub placed close to your listening position (which can be disguised as a coffee/side table). i wouldn't spend too much on sub/ripole drivers. for a 18" ripole sub, 2x faital pro 18FH510 comes to my mind.
in your main speaker, i would advise not to mix drivers... what i mean is if you are using vintage drivers, stick to the theme... saba+saba+altec is good... if you are going to use rubber surround modern drivers then perhaps add 2x peerless sls woofers to your seas exotic (like linkwitz and naonote designs)...
a note on your mid bass co point... in proven OB designs with 8" mid driver, the crossover point is usually around 250hz... might have sth to do with the null caused by the floor bounce... in your designs you have deviated significantly from that fr.... compare saba vs. seas with the same 250hz co point...and also see how that affects the bass perception.
not enough bass (punch) with 416A on OB
i would check the vintage altecs to see if they are alright. best would be to have them measured for magnet power. vintage alnicos can lose magnet power and can also be recharged (i think). if you can't have them checked professionally, connect them directly to your amp and give them a listen individually and compare each against the other... also observe the cone move with bass heavy music.
i also recommend high passing your OB woofers with a steep filter on or just above their Fs to protect them for over-excursion.
your first OBs with saba+altec are very similar to lampizator's endorphin project:
Endorphine from Kingston Kitchen
he is very experienced and loves the saba altec combo....and i agree with him. so do not give up on your sabas and altecs yet.
with what you have in hand, you can always add some subwoofer(s) to have better deeper bass. if you are living in a flat, boxed subs can be difficult with neighbors. in that case you can try a separate ripole sub placed close to your listening position (which can be disguised as a coffee/side table). i wouldn't spend too much on sub/ripole drivers. for a 18" ripole sub, 2x faital pro 18FH510 comes to my mind.
in your main speaker, i would advise not to mix drivers... what i mean is if you are using vintage drivers, stick to the theme... saba+saba+altec is good... if you are going to use rubber surround modern drivers then perhaps add 2x peerless sls woofers to your seas exotic (like linkwitz and naonote designs)...
a note on your mid bass co point... in proven OB designs with 8" mid driver, the crossover point is usually around 250hz... might have sth to do with the null caused by the floor bounce... in your designs you have deviated significantly from that fr.... compare saba vs. seas with the same 250hz co point...and also see how that affects the bass perception.
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I've heard a lot of OB speakers and it's rare to get low end slam out of them. Even with 21" woofers on a large baffle that were flat to 22Hz, no slam.
IMO, that sound comes from box speaker, or from things like them (a big drum). It's a familiar sound because so much music is now amplified. It's mostly an artifact of large woofers in too small boxes with 100s of watts of power. Where would Rock or Reggae be without it?
OB bass tends to be more natural - and we aren't used to that. The only OB speakers I've heard with box-like slam have used high efficiency 18" woofers with massive EQ to flatten them.
IMO, that sound comes from box speaker, or from things like them (a big drum). It's a familiar sound because so much music is now amplified. It's mostly an artifact of large woofers in too small boxes with 100s of watts of power. Where would Rock or Reggae be without it?
OB bass tends to be more natural - and we aren't used to that. The only OB speakers I've heard with box-like slam have used high efficiency 18" woofers with massive EQ to flatten them.
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