Rudolf said:
Are you referring to something like this:
http://www.gradient.fi/products/revolution/sivu3.html
Gradient Revolution with turning woofersolution. Presently my speakers are along the longer wall (5,2m) and it's pretty much the only way. Room is 3,7m wide so placing speakers to longer walls puts listening position just along the other wall messing up bass department. And even this 1,5m distance to front wall couldn't be achieved. 1m at the max. Therefore any dipolesolution needs to be along the sidewalls in this present positioning. 1,5m to frontwall and pointed towards listener or just along the walls (30 degree off axis from the listening spot).
Response can be equalized but with these panels alone I don't want to do that. It just runs those lowmid drivers to wild excursions and it still doesn't play that much. 80-250Hz they should be pretty excellent.
But overally the problem is there. No mather how big dipoles are used. Boosting lowend might give more but it also increases sound reflected from the frontwall and therefore eat away low bass. Would a monopole or two make better solution..
Jussi
Rudolf said:
Rudolf,
Then this is just a W with shortened D to push peak up in frequency with corresponding loss in LF output? Positioned just like a W?
Rudolf said:
How can it be placed woofers parallel to (front) wall without directing the null at the listening area? Why would either sidewall or front wall scenario work best in mono?
cheers,
AJ
AJinFLA said:
Check the positioning options from those Revolutions. It's possible but naturally you don't listen bass from on axis, pretty close from 60 degrees off axis in normal symmetric listening triangle. This sacrifices 6dB from the output but at the same time front wall boosts dipole that 6dB balancing things. This thing actually work but not so good if the top system is also open baffle while it runs way too close to front wall. Revolution uses cardioid midrange so frontwall isn't a problem.
Jussi
An externally hosted image should be here but it was not working when we last tested it.
The 40 second sketch LOL. Am I on the right page?
cheers,
AJ
AJinFLA said:
Yes and yes. The plan of the developer was to "smear" the resonance peak somehow by shortening D at the outside of the W only. This allowed for equalisation with a subwoofer module without need for a full fletched notch filter.
Your 40 sec sketch already shows it. Just don´t place the W just in front or at a 90° angle to the side of the seat. Moving the W on the front/side wall nearer to one corner (not into the corner) should get the null plane out of the way. Rotating the W some degrees wouldn´t hurt either.
Regarding mono: I just wanted to point out that moving stereo woofers around this way might not help the imaging. And as Jussy already mentioned: Dipole panels for mid/high need to be positioned separately from the Ws.
Both scethed places work but not like that. Sidewall position looks like about 45 degrees off axis from the listener. This is propably ok. It's possible to turn the wooferstructure towards listener but depending on it's size radiation pattern might not turn. And this is because the wall doubles "D" value, increases output and dominate radiation pattern behavior.
Frontwall positioning is also possible if you have very wide and propably not that deep room. It doesn't work like scetched since listener is left to null point but using two and spreading them wider works. For example have +5m wide room, place woofers along the frontwall 3m apart and have the listening position 3m from each woofer. Listener is still left to 60 degree off axis position but I already mensioned about this. Compared to free field positioning without wallboost placing along frontwall adds another 6dB to output, the number system is loosing in direct radiation towards the listener because the off axis listening. And depending on mid-tweeter solution these propably require DSP delays to match the top in time level.
But in my case frontwall positions are off. I've deliberately placed my panels along the long wall to achieve enough space behind the speakers and behind listener. Frontwall is only 3,7m wide and while mains are 2,5m from me and 1,5m from frontwall I'd need at least 4m wide positions for the woofers to achieve symmetric triangle and 60 degree off axis operation. 4m plus 1-2m to each side to give the dipole a chance. Not enough space. Woofers along the sidewalls, just outside of my mains is the solution if dipolewoofers offer the answer.
Same positions are also available for stereomonopole setup. And I can use frontwall center position with mono monopole setup. But how operational neither of them is and at the same time is plain increase in displacement the answer to lack of grunt in dipole? Room is still eating away that low bass in dipole.
Jussi
Frontwall positioning is also possible if you have very wide and propably not that deep room. It doesn't work like scetched since listener is left to null point but using two and spreading them wider works. For example have +5m wide room, place woofers along the frontwall 3m apart and have the listening position 3m from each woofer. Listener is still left to 60 degree off axis position but I already mensioned about this. Compared to free field positioning without wallboost placing along frontwall adds another 6dB to output, the number system is loosing in direct radiation towards the listener because the off axis listening. And depending on mid-tweeter solution these propably require DSP delays to match the top in time level.
But in my case frontwall positions are off. I've deliberately placed my panels along the long wall to achieve enough space behind the speakers and behind listener. Frontwall is only 3,7m wide and while mains are 2,5m from me and 1,5m from frontwall I'd need at least 4m wide positions for the woofers to achieve symmetric triangle and 60 degree off axis operation. 4m plus 1-2m to each side to give the dipole a chance. Not enough space. Woofers along the sidewalls, just outside of my mains is the solution if dipolewoofers offer the answer.
Same positions are also available for stereomonopole setup. And I can use frontwall center position with mono monopole setup. But how operational neither of them is and at the same time is plain increase in displacement the answer to lack of grunt in dipole? Room is still eating away that low bass in dipole.
Jussi
Rattling
Hi
Jussi, your open baffle is very special in that you use a sandwich structure with a steel plate in the middle. With such a extreme construction I guess you have to be very decisive and attentive to all details to finally overcome your rattling problems.
Basically the OB itself acts like a loudspeaker membrane below and above breakup.
http://youtube.com/watch?v=Zkox6niJ1Wc
"http://youtube.com/watch?v=Zkox6niJ1Wc"
Considering the huge area of the OB you can calculate a really minimal movement that already radiates sound at levels exceeding what you want to tolerate as coloration / distortion.
So lets zoom into some micro mechanic that may be important to your specific problems.
The force that makes your OB move, comes mostly from the loudspeaker motor that has to accelerate the mass of the loudspeaker diaphragm and to a smaller extent it comes from the pressure difference from front versus back side of the baffle. I think this correlates to the relative bad efficiency of speakers in general.
To distinguish between this two forces is only important for the overall picture. Basically the movement of the OB can be seen as a side effect from energy transfer that is not 100% transmitted to the floor.
A spine would stiffen the structure and provide a better path for the energy to flow. It has to have a direct and strong path right from the speakers ( as close to the baskets as possible ) to the bottom plate.
This should work at least for low frequencies. At higher frequencies I doubt that this holds true as the spine itself becomes kind of an complex oscillating system.
An other effect of attaching a spine would be that you add a null at every point you weld it to the OB ( frequency dependant like above). A disadvantage may be that you increase the radiating area by some extent.
For damping issues of the steel plate, lets imagine the OB without any spine. Basically I see 2 very different possibilities you can choose from.
You already made the step towards a sandwich structure.
As the steel in the middle does not have significant losses you will need a really efficient way to absorb the moving energy. Applying 2 cm of recycled rubber each side would not help much for example, as this material it is way too limp in such a configuration.
One way to absorb energy is to make the outer plates stiff as well and put a absorbing material in between. 1 – 2 mm of recycled rubber would be enough I think. This way the sandwich acts very much like a lorry spring that is made of a package of steel plates that also absorb some energy by friction when bent. All layers – front layer - rubber – steel – rubber – back layer – should be glued all over the area. better than just screwed together at some points. Almost any glue will work for that. It must not be very strong nor especially stiff or elastic.
Energy will be absorbed mostly through the elastic material between the layers ( recycled rubber for example ) and not necessarily through the outer layers. There might also be some better soft materials than recycled rubber, which actually does not have very much of inner damping.
To make the sandwich like the lorry spring without any elastic material in between will cause noise due to stick slip effects when one surface moves in relation to the other.
For the same reason you should avoid any screws going through all layers. This makes the elastic layer obsolete.
The loudspeakers MUST be attached to the steel plate otherwise you just accelerate and move the front plate that can not efficiently transmit the energy to the bottom plate.
An other way to absorb energy is to attach a relatively stiff material with relatively high inner losses right to the steel plate.
This could be MDF or something like.
Here the energy is absorbed in the outer ( MDF- ) layers only and you have to glue the sandwich with the most strong and brittle glue you can find. A possibility would be polyurethene that slightly expands and becomes very brittle . But those I know of, harden very fast and this will be a challenge for the large area you have to glue.
One advantage of that configuration would be that you don't necessarily have to attach the speakers to the steel plate. Screws going through all layers would have no negative impact but rather make sure the layers will not separate over time.
A slight improvement of the baffle stiffness also would happen.
Mounting the speaker right to the outer layer will work just fine.
Attaching the basket of a loudspeaker to a metal plate is not that simple as it looks from first glance.
I would suggest to use spacers ( washers ) to keep the rest of the basket distant from the steel plate and to use acrylic mass or foam to seal. If you directly attach the basket to the steel plate the intersections between the screws may vibrate very little and cause rattling when bouncing against the steel plate.
If you mount at wood or MDF this is much less a problem as the basket sinks in to some degree.
If you fully glue the basket ( like Dynaudio used to do with its ever elastic lasting LX-2 ), well in case of repair you'll face hard times but otherwise its optimal. I would NOT suggest silicone for this as it has almost no inner losses and never sounded right to me.
Greetings
Michael
Hi
Jussi, your open baffle is very special in that you use a sandwich structure with a steel plate in the middle. With such a extreme construction I guess you have to be very decisive and attentive to all details to finally overcome your rattling problems.
Basically the OB itself acts like a loudspeaker membrane below and above breakup.
http://youtube.com/watch?v=Zkox6niJ1Wc
"http://youtube.com/watch?v=Zkox6niJ1Wc"
Considering the huge area of the OB you can calculate a really minimal movement that already radiates sound at levels exceeding what you want to tolerate as coloration / distortion.
So lets zoom into some micro mechanic that may be important to your specific problems.
The force that makes your OB move, comes mostly from the loudspeaker motor that has to accelerate the mass of the loudspeaker diaphragm and to a smaller extent it comes from the pressure difference from front versus back side of the baffle. I think this correlates to the relative bad efficiency of speakers in general.
To distinguish between this two forces is only important for the overall picture. Basically the movement of the OB can be seen as a side effect from energy transfer that is not 100% transmitted to the floor.
A spine would stiffen the structure and provide a better path for the energy to flow. It has to have a direct and strong path right from the speakers ( as close to the baskets as possible ) to the bottom plate.
This should work at least for low frequencies. At higher frequencies I doubt that this holds true as the spine itself becomes kind of an complex oscillating system.
An other effect of attaching a spine would be that you add a null at every point you weld it to the OB ( frequency dependant like above). A disadvantage may be that you increase the radiating area by some extent.
For damping issues of the steel plate, lets imagine the OB without any spine. Basically I see 2 very different possibilities you can choose from.
You already made the step towards a sandwich structure.
As the steel in the middle does not have significant losses you will need a really efficient way to absorb the moving energy. Applying 2 cm of recycled rubber each side would not help much for example, as this material it is way too limp in such a configuration.
One way to absorb energy is to make the outer plates stiff as well and put a absorbing material in between. 1 – 2 mm of recycled rubber would be enough I think. This way the sandwich acts very much like a lorry spring that is made of a package of steel plates that also absorb some energy by friction when bent. All layers – front layer - rubber – steel – rubber – back layer – should be glued all over the area. better than just screwed together at some points. Almost any glue will work for that. It must not be very strong nor especially stiff or elastic.
Energy will be absorbed mostly through the elastic material between the layers ( recycled rubber for example ) and not necessarily through the outer layers. There might also be some better soft materials than recycled rubber, which actually does not have very much of inner damping.
To make the sandwich like the lorry spring without any elastic material in between will cause noise due to stick slip effects when one surface moves in relation to the other.
For the same reason you should avoid any screws going through all layers. This makes the elastic layer obsolete.
The loudspeakers MUST be attached to the steel plate otherwise you just accelerate and move the front plate that can not efficiently transmit the energy to the bottom plate.
An other way to absorb energy is to attach a relatively stiff material with relatively high inner losses right to the steel plate.
This could be MDF or something like.
Here the energy is absorbed in the outer ( MDF- ) layers only and you have to glue the sandwich with the most strong and brittle glue you can find. A possibility would be polyurethene that slightly expands and becomes very brittle . But those I know of, harden very fast and this will be a challenge for the large area you have to glue.
One advantage of that configuration would be that you don't necessarily have to attach the speakers to the steel plate. Screws going through all layers would have no negative impact but rather make sure the layers will not separate over time.
A slight improvement of the baffle stiffness also would happen.
Mounting the speaker right to the outer layer will work just fine.
Attaching the basket of a loudspeaker to a metal plate is not that simple as it looks from first glance.
I would suggest to use spacers ( washers ) to keep the rest of the basket distant from the steel plate and to use acrylic mass or foam to seal. If you directly attach the basket to the steel plate the intersections between the screws may vibrate very little and cause rattling when bouncing against the steel plate.
If you mount at wood or MDF this is much less a problem as the basket sinks in to some degree.
If you fully glue the basket ( like Dynaudio used to do with its ever elastic lasting LX-2 ), well in case of repair you'll face hard times but otherwise its optimal. I would NOT suggest silicone for this as it has almost no inner losses and never sounded right to me.
Greetings
Michael
shy bass
Hi
Jussi, one speaker seems to drop below 500 Hz ??
Did you set the DCX to lock both channels?
Greetings
Michael
Hi
Jussi, one speaker seems to drop below 500 Hz ??
An externally hosted image should be here but it was not working when we last tested it.
Did you set the DCX to lock both channels?
Greetings
Michael
Re: shy bass
This is the case. Whole panel is 50mm thick with 16mm steel inside. 2-3mm playroom between the layers for some dampingmaterial before glue.
This is the solution I thought to use. With the frontplate covering the flange I can't use that large bolts very well and when whole thing is glued together I have to tear it apart anyway if something is busted. Naturally the tweeter can be replaced without dramatic procedures.
For really solid installation there are some liquid metal type glues that really do the job but how advisable are they?
Yep. Both channels are locked and on axis freefield measurements are as close as I can measure them inside. But the speaker positions aren't that symmetrical. Right speaker has TV-table and AV setup at that sidewall and left speaker has a couch close to it. Unfortunate but I can't do better. Placing the speakers along the tv-set would make it more symmetrical but it would be difficult to achieve even 1m distance to frontwall and only dream of 1,5m I presently use. And in that case listening position would also be very close to wall as it's presently nice 1,5m off it.
This is actually one issue I'm worried about with dipolewoofers. Left woofercolumn would be pretty much behind the couch. How but does it effect below 100Hz, I don't know. Single monopole is easier since I can put it just along the frontwall between the speakers.
I actually tried one commercial model in this room. Finnish Amphion Impact which uses 12" XLS woofer in closed cabinet. Pretty decent behavior overall but I couldn't get it 100% fixed. First I tried 40-50Hz highpass to mains and put some long delay to fix timing. But the subwoofer at that position suffers from the same 33Hz centered roommode as the dipoles so it didn't sound that food. Actually dipolepanels 33Hz peak isn't that bad since 2x10" can't play that much those frequences. With monopole it's much bigger problem.
Ok. So that didn't work. Then I wired the subwoofer from Behringers lowmid channels. This didn't allow me to use highpass for the mains and longdelay effect didn't do any good but I could fix the parametric EQ to fix both lowmid and subwoofer region below 100Hz. This is the measured result (see attachment).
Overall balance isn't propably the same as with earlier roomresponse since I've been tweaking it along the way.
Sounded.. Well. Decent. But propably not good anough that I would go for that exact solution. More physical slam as expected but the overall detaillevel and snap suffered. And here is the problem. I don't know what causes that. I had the subwoofer only couple of days so I didn't have that much time to tweak it. Overally my possibilities to adjust things was limited and I guess I'd invest DEQ2496 just for the room balancing if I choose monopole woofer. That way I can put the signal digitally into the DEQ, do all necessary room EQ business, take digital signal from DEQ to DCX where make main speakers crosses and take analog signal from DEQ to separated monopolesubwoofer. Sub needs lowpass of it's own and this allows me to use DCX long delay to fix the timing.
Ok. So was it just poorly tweaked with limited adjustment possibilities or overally poor solution to this room with any adjustments (the worse scenario).
I guess both have some compromisses and risks. Dipolecolumns and monopolesub. With dipole I have to say goodbye below 30Hz frequences which is ok by me if all else works well. On the other hand I thought to go multichannel at some point and there monopoleslam from LFE channel is a nice figure.
We have a metalplate mangle at work and I could use it to make Genelec style LSE cabinet (http://www.genelec.com/learning-center/technology-tutorials/lse/). Pretty good idea with these present drivers that fit into small cabinets but need long and big diameter vent. Place 15" PA woofer into it and play down to 20-22Hz. Other solution could be 18" woofer in similar size closed cabinet. Not that punchy 20-30Hz but pretty equal above that and by sacrificing some output it's possible to extend response well below 20Hz. I guess 18" monopole in this size room is ... Well. Overkilling. But I prefer using large cones to move air rather than small cones moving mad.
Some people have wondered about this fixation to PA woofers but I like the idea. Large cone, not that much linear excursion, low(ish) mms for it's size, powerful motor and plenty of progressive suspension secured mechanical limits. Big 18" RCF woofer I had in mind has 5dB more linear excursion limited SPL potential compared to 12" XLS. Personally I don't know is that enough. At least I got that 12" XLS in Amphion Impact move pretty much. Perhaps 15" driver with same linearexcursion with vented cabinet assistance would do the trick....
Jussi
mige0 said:
This is the case. Whole panel is 50mm thick with 16mm steel inside. 2-3mm playroom between the layers for some dampingmaterial before glue.
This is the solution I thought to use. With the frontplate covering the flange I can't use that large bolts very well and when whole thing is glued together I have to tear it apart anyway if something is busted. Naturally the tweeter can be replaced without dramatic procedures.
For really solid installation there are some liquid metal type glues that really do the job but how advisable are they?
Jussi, one speaker seems to drop below 500 Hz ??
Did you set the DCX to lock both channels?
Yep. Both channels are locked and on axis freefield measurements are as close as I can measure them inside. But the speaker positions aren't that symmetrical. Right speaker has TV-table and AV setup at that sidewall and left speaker has a couch close to it. Unfortunate but I can't do better. Placing the speakers along the tv-set would make it more symmetrical but it would be difficult to achieve even 1m distance to frontwall and only dream of 1,5m I presently use. And in that case listening position would also be very close to wall as it's presently nice 1,5m off it.
This is actually one issue I'm worried about with dipolewoofers. Left woofercolumn would be pretty much behind the couch. How but does it effect below 100Hz, I don't know. Single monopole is easier since I can put it just along the frontwall between the speakers.
I actually tried one commercial model in this room. Finnish Amphion Impact which uses 12" XLS woofer in closed cabinet. Pretty decent behavior overall but I couldn't get it 100% fixed. First I tried 40-50Hz highpass to mains and put some long delay to fix timing. But the subwoofer at that position suffers from the same 33Hz centered roommode as the dipoles so it didn't sound that food. Actually dipolepanels 33Hz peak isn't that bad since 2x10" can't play that much those frequences. With monopole it's much bigger problem.
Ok. So that didn't work. Then I wired the subwoofer from Behringers lowmid channels. This didn't allow me to use highpass for the mains and longdelay effect didn't do any good but I could fix the parametric EQ to fix both lowmid and subwoofer region below 100Hz. This is the measured result (see attachment).
Overall balance isn't propably the same as with earlier roomresponse since I've been tweaking it along the way.
Sounded.. Well. Decent. But propably not good anough that I would go for that exact solution. More physical slam as expected but the overall detaillevel and snap suffered. And here is the problem. I don't know what causes that. I had the subwoofer only couple of days so I didn't have that much time to tweak it. Overally my possibilities to adjust things was limited and I guess I'd invest DEQ2496 just for the room balancing if I choose monopole woofer. That way I can put the signal digitally into the DEQ, do all necessary room EQ business, take digital signal from DEQ to DCX where make main speakers crosses and take analog signal from DEQ to separated monopolesubwoofer. Sub needs lowpass of it's own and this allows me to use DCX long delay to fix the timing.
Ok. So was it just poorly tweaked with limited adjustment possibilities or overally poor solution to this room with any adjustments (the worse scenario).
I guess both have some compromisses and risks. Dipolecolumns and monopolesub. With dipole I have to say goodbye below 30Hz frequences which is ok by me if all else works well. On the other hand I thought to go multichannel at some point and there monopoleslam from LFE channel is a nice figure.
We have a metalplate mangle at work and I could use it to make Genelec style LSE cabinet (http://www.genelec.com/learning-center/technology-tutorials/lse/). Pretty good idea with these present drivers that fit into small cabinets but need long and big diameter vent. Place 15" PA woofer into it and play down to 20-22Hz. Other solution could be 18" woofer in similar size closed cabinet. Not that punchy 20-30Hz but pretty equal above that and by sacrificing some output it's possible to extend response well below 20Hz. I guess 18" monopole in this size room is ... Well. Overkilling. But I prefer using large cones to move air rather than small cones moving mad.
Some people have wondered about this fixation to PA woofers but I like the idea. Large cone, not that much linear excursion, low(ish) mms for it's size, powerful motor and plenty of progressive suspension secured mechanical limits. Big 18" RCF woofer I had in mind has 5dB more linear excursion limited SPL potential compared to 12" XLS. Personally I don't know is that enough. At least I got that 12" XLS in Amphion Impact move pretty much. Perhaps 15" driver with same linearexcursion with vented cabinet assistance would do the trick....
Jussi
Attachments
Hi
Jussi, left and right FR match much better now.
There still is a stong emphasis on the mids around 500 Hz.
Don't be shy with the Behringer EQ !!!
Rudolf, thanks for responding to the questions concerning dipol / ripol positioning.
Greetings
Michael
Jussi, left and right FR match much better now.
There still is a stong emphasis on the mids around 500 Hz.
Don't be shy with the Behringer EQ !!!
Rudolf, thanks for responding to the questions concerning dipol / ripol positioning.
Greetings
Michael
mige0 said:
Don't need to. It's meant to be there. I presently use 3.2.2 version of my filter. 3.2 was the latest flat fixed on axis response I've used. Here are the individual speakers responses. 6-12Khz bump is caused by my present measuring microphone.
Jussi
Attachments
And here is left speakers +-45 degree off axis measurements with the same crossover setup.
Measurements can't be 100% identical since I'm measuring them in room so they can't be in identical position, I can't measure angles identically and so on. Just basic measurements of how the overall thing works.
Jussi
Measurements can't be 100% identical since I'm measuring them in room so they can't be in identical position, I can't measure angles identically and so on. Just basic measurements of how the overall thing works.
Jussi
Attachments
And finally left channel room response with 100Hz and 33Hz parametric EQ treatment along with overall below 100Hz level adjustment. Both room responses are measured from listening position (250cm away) with 300ms window and 1/6th octave smoothing.
I guess you next ask why I changed the balance to the one posted earlier. Simple. This balance doesn't sound good. It's too flat room response considering typical recordings. Tiring midrange and treble forward system.
If you take a room response from any typical box speaker which are used in recording industry and what people normally use for listening they have roll off in the power response towards treble. Therefore their roomresponse acts similar. Constant directivity is a nice thing but recordings don't support it. So I need to make some adjustments. Lower midrange and tweeter levels a bit to come up with satisfying result. But the directivity is still constant. Those rather smooth 45 degree and 60 degree responses are still there. They just roll off similarily as the on axis response. Which leads to very similar sound balance while listening off axis. I can listen there 45 degrees off axis and still have very similar balance than on axis. Naturally soundstage doesn't work that well but overally speakers have very wide usable sweetspot.
Jussi
I guess you next ask why I changed the balance to the one posted earlier. Simple. This balance doesn't sound good. It's too flat room response considering typical recordings. Tiring midrange and treble forward system.
If you take a room response from any typical box speaker which are used in recording industry and what people normally use for listening they have roll off in the power response towards treble. Therefore their roomresponse acts similar. Constant directivity is a nice thing but recordings don't support it. So I need to make some adjustments. Lower midrange and tweeter levels a bit to come up with satisfying result. But the directivity is still constant. Those rather smooth 45 degree and 60 degree responses are still there. They just roll off similarily as the on axis response. Which leads to very similar sound balance while listening off axis. I can listen there 45 degrees off axis and still have very similar balance than on axis. Naturally soundstage doesn't work that well but overally speakers have very wide usable sweetspot.
Jussi
Attachments
Yeah! Lunacy is back!
Here is my new evolution version of this dynamic dipole. Only on scetch so far. Main compromises with my former design are thought through and hopefully upgraded to whole new level.
Some thoughts in my WWMTM compared to new ideas:
- Steel + MDF structure
Well. I didn't get it finished at any time so I can't say anything definite. Very heavy. New one from MDF or solid wood. Bigger design, still at least adequate weight.
- Point source tweeter
Yes. Used 1" Seas aluminium dome in my WWMTM. Good but it doesn't match vertical directivity of MTM. New ones have horizontally waveguided Pro5i Fountek ribbons (distorsion measurement attached. Note: measured without waveguide).
- Overall WWMTM configuration
It isn't symmetrical. Don't know how big issue though but I like the idea of symmetrical vertical dispersion (which WWMTMWW delivers). With well designed crossover it delivers pretty even vertical radiation pattern.
- 2x10" bass
It actually even wasn't meant to handle everything but I didn't build the separated woofers so the setup run short compared to it's commercial version (AA Beethoven). Decent for most music in my modest size room but didn't work at all with AV material and mostly caused the biggest bottleneck of the system when it comes to SPL and dynamics.
New version has 4x12" SLS woofers in 500mm wide baffle. In theory 15dB more capacity. Should make a difference.
- Only front firing tweeter.
Well. It lacks the best air. New one has my former models 1" waveguided aluminium at the back. Have to see what kind of filterin would give the best result.
- Thoughts of 4-way
Too complicated. At least to me and my purposes. So 3-way with heavier construction it is.
Overall. Shoot it down while you can... 😀
Here is my new evolution version of this dynamic dipole. Only on scetch so far. Main compromises with my former design are thought through and hopefully upgraded to whole new level.
Some thoughts in my WWMTM compared to new ideas:
- Steel + MDF structure
Well. I didn't get it finished at any time so I can't say anything definite. Very heavy. New one from MDF or solid wood. Bigger design, still at least adequate weight.
- Point source tweeter
Yes. Used 1" Seas aluminium dome in my WWMTM. Good but it doesn't match vertical directivity of MTM. New ones have horizontally waveguided Pro5i Fountek ribbons (distorsion measurement attached. Note: measured without waveguide).
- Overall WWMTM configuration
It isn't symmetrical. Don't know how big issue though but I like the idea of symmetrical vertical dispersion (which WWMTMWW delivers). With well designed crossover it delivers pretty even vertical radiation pattern.
- 2x10" bass
It actually even wasn't meant to handle everything but I didn't build the separated woofers so the setup run short compared to it's commercial version (AA Beethoven). Decent for most music in my modest size room but didn't work at all with AV material and mostly caused the biggest bottleneck of the system when it comes to SPL and dynamics.
New version has 4x12" SLS woofers in 500mm wide baffle. In theory 15dB more capacity. Should make a difference.
- Only front firing tweeter.
Well. It lacks the best air. New one has my former models 1" waveguided aluminium at the back. Have to see what kind of filterin would give the best result.
- Thoughts of 4-way
Too complicated. At least to me and my purposes. So 3-way with heavier construction it is.
Overall. Shoot it down while you can... 😀
Attachments
Former speakers have W18E001 Excels. No need to disband them. Waveguided Pro5i should handle 1,5kHz 4th order Linkwitz-Riley so setup should rip pretty much everything out of those Excels without breakup compromisses.
I used them with 250Hz 2nd order Linkwitz-Riley in my WWMTM dipoles. Not that much cone movement, should be safe.
It's based on my own prototype. Already tested it and seemed operational but without curved edges it caused pretty severe diffraction problems. Evolution version with curved edge baffle should solve this.
- Status
- Not open for further replies.