As I am sometimes just wandering about some speaker designs, something came to my mind.
A little bit before the covid pandemic started I made a top speaker for a friend.
Based on the SMT212 but using only 1 12" driver.
As Always it was a compromise and i didn't used the most expensive drivers.
I used the PA310 for the 12" driver and a PRV compression driver.
I was amazed about how good this simple design can perform.
As I see it the mid section has a horn/waveguide that boosts the higher mid frequenties till around 200-300Hz.
Then it is also vented but tuned relatively high giving extention to around 100Hz with a sensitivity more then 100db/w/m.
(I measured around 102db)
If you would tune a normal front loaded reflex speaker this high it would have a bump. But the combination with the horn (or more like a waveguide?) makes for a flat response.
This is the way this cab works I think?
Having a sensitivity of around 102db makes it loud with a lot of dynamic. A really good sounding PA/Party speaker.
When I was thinking for a nice 3way top it got me thinking again about this cab.
I have made Some Xtro's years ago. They where not a perfect build but didn't sound to bad.
The 8PE21 is a good mid driver but has a difficult time in the Xtro I think.
I used the beyma 15p80Fe for the low mid. Incredible slam and punch but would be nice if it could go a little bit lower.
They where also HEAVY to say the least.
So back to the SMT212.
What if this principle was used with some good 15" drivers.
The 15P80Nd is the Nd version with a lot less weight.
I tried a quick simulation in Hornresp with 2 of these.
I got around 106db/w/m (2Pi, I find it hard to believe....)
-3db around 80Hz and -10db around 65Hz
The high response goes to around 200-300Hz but with this priciple I have noticed it will go higher as simulated. (the 12" I used had a response till around 2kHz, I did cross at around 1k5 or something)
I wanted a 3way so was thinking to put a mid driver with horn above these 2 15" drivers and make them the same length (if possible), it makes delay problems almost non existent.
Then I would place a 1" compression driver on a smaller horn and put it on the front of the second 15" driver's mouth.
(The Xtro uses this layout)
The biggest issue I see is the mid section.
While the 8PE21 is one of the better mid drivers, getting in line with 2 15" drivers having a sensitivity of 106db and a continous rating of 1600w I don't think it's gonna cut it.
I hope to cross at around 400Hz, this would put less strain on the mid driver.
Then the next issue is the compression driver.
I like the sound of a 1" driver not crossed to low.
Problem is that getting in line with the low section at full tilt is difficult. (horn resp says 138db)
The beyma CD10Nd is on of my favorites. I think it can hold if not crossed to low.
Therefore the mid section should go high enough.
Any nice 10" mid drivers? or should I use dual 8PE21 but this will have an impact on high response.
Then one last thing.
Altough it would be a crazy Idea, A Passive crossover could be designed as the mid and low section are acoustically aligned, the high is not but maybe some crossover tricks can be used for this.
Active crossing is the way to go for best performance but if passive is possible this could be a compromise for easy setup.
Would be a really big crossover for these powers...
If I could get these issues solved, This would make a nice top with some potential and not the difficult to build.
Don't know if I would build it but I like to think about ideas that pop up in my head.
Any comments and ideas are welcome
A little bit before the covid pandemic started I made a top speaker for a friend.
Based on the SMT212 but using only 1 12" driver.
As Always it was a compromise and i didn't used the most expensive drivers.
I used the PA310 for the 12" driver and a PRV compression driver.
I was amazed about how good this simple design can perform.
As I see it the mid section has a horn/waveguide that boosts the higher mid frequenties till around 200-300Hz.
Then it is also vented but tuned relatively high giving extention to around 100Hz with a sensitivity more then 100db/w/m.
(I measured around 102db)
If you would tune a normal front loaded reflex speaker this high it would have a bump. But the combination with the horn (or more like a waveguide?) makes for a flat response.
This is the way this cab works I think?
Having a sensitivity of around 102db makes it loud with a lot of dynamic. A really good sounding PA/Party speaker.
When I was thinking for a nice 3way top it got me thinking again about this cab.
I have made Some Xtro's years ago. They where not a perfect build but didn't sound to bad.
The 8PE21 is a good mid driver but has a difficult time in the Xtro I think.
I used the beyma 15p80Fe for the low mid. Incredible slam and punch but would be nice if it could go a little bit lower.
They where also HEAVY to say the least.
So back to the SMT212.
What if this principle was used with some good 15" drivers.
The 15P80Nd is the Nd version with a lot less weight.
I tried a quick simulation in Hornresp with 2 of these.
I got around 106db/w/m (2Pi, I find it hard to believe....)
-3db around 80Hz and -10db around 65Hz
The high response goes to around 200-300Hz but with this priciple I have noticed it will go higher as simulated. (the 12" I used had a response till around 2kHz, I did cross at around 1k5 or something)
I wanted a 3way so was thinking to put a mid driver with horn above these 2 15" drivers and make them the same length (if possible), it makes delay problems almost non existent.
Then I would place a 1" compression driver on a smaller horn and put it on the front of the second 15" driver's mouth.
(The Xtro uses this layout)
The biggest issue I see is the mid section.
While the 8PE21 is one of the better mid drivers, getting in line with 2 15" drivers having a sensitivity of 106db and a continous rating of 1600w I don't think it's gonna cut it.
I hope to cross at around 400Hz, this would put less strain on the mid driver.
Then the next issue is the compression driver.
I like the sound of a 1" driver not crossed to low.
Problem is that getting in line with the low section at full tilt is difficult. (horn resp says 138db)
The beyma CD10Nd is on of my favorites. I think it can hold if not crossed to low.
Therefore the mid section should go high enough.
Any nice 10" mid drivers? or should I use dual 8PE21 but this will have an impact on high response.
Then one last thing.
Altough it would be a crazy Idea, A Passive crossover could be designed as the mid and low section are acoustically aligned, the high is not but maybe some crossover tricks can be used for this.
Active crossing is the way to go for best performance but if passive is possible this could be a compromise for easy setup.
Would be a really big crossover for these powers...
If I could get these issues solved, This would make a nice top with some potential and not the difficult to build.
Don't know if I would build it but I like to think about ideas that pop up in my head.
Any comments and ideas are welcome