YES!
And ideally with a fitting waveguide to combine with the tweeter.
But not sure if this will happen, it doesn't fit their lineup well. But boy ... a 3,5" dome fitting their big tweeter and going down lower as the 3"s ... I would think seriously about by building my reference speaker new for the last time - again. 🤓
And ideally with a fitting waveguide to combine with the tweeter.
But not sure if this will happen, it doesn't fit their lineup well. But boy ... a 3,5" dome fitting their big tweeter and going down lower as the 3"s ... I would think seriously about by building my reference speaker new for the last time - again. 🤓
Mmh, there are M174 + T34 drivers from Bliesma available that might fit the needs to achieve more SPL than M74 + T25, at least I assume these are made therefore by providing more membrane surface and more thermal capability by larger domes, coils + motors. Or take 2x M74 + T34 like @profiguy. Purifi 1.5" tweeter has very nice performance but appears a bit overpriced to me in comparison to T34A. But another good option would always be welcome.
Last edited:
Regarding the SPL topic in general:
3" mid-domes from Bliesma and Volt available to the DIY cowd can provide clean peak SPL range up to >115dB@1m, with the advantage of very low thermal modulation, wide dispersion and lack of resonances in the passband, and that is very loud in comparison to usual high quality 4-5" cone mids.
While this is valid in comparison with "typical HiFi cone drivers", there are out 5" PA mids that can also deliver SPL in such range, some are really nice made and have shorting rings and caps. I remember distortion measurements in german DIY forum of a Faital PA mid with low distortion @110db, and the manufacturer distortion measurement of this 5" BMS midwoofer is also nice. There are other 5" PA drivers out that look tasty, TSP based sims show that 110-115 dB is often usual peak SPL capability.
So, can a good PA 5" mid be an alternative to expensive 3" mid-domes from Bliesma and Volt for high-quality-high-SPL applications?
(Of course dispersion/radiation will be narrower with the larger 5" cone in the passband - but i see this first as a property, not a drawback.)
3" mid-domes from Bliesma and Volt available to the DIY cowd can provide clean peak SPL range up to >115dB@1m, with the advantage of very low thermal modulation, wide dispersion and lack of resonances in the passband, and that is very loud in comparison to usual high quality 4-5" cone mids.
While this is valid in comparison with "typical HiFi cone drivers", there are out 5" PA mids that can also deliver SPL in such range, some are really nice made and have shorting rings and caps. I remember distortion measurements in german DIY forum of a Faital PA mid with low distortion @110db, and the manufacturer distortion measurement of this 5" BMS midwoofer is also nice. There are other 5" PA drivers out that look tasty, TSP based sims show that 110-115 dB is often usual peak SPL capability.
So, can a good PA 5" mid be an alternative to expensive 3" mid-domes from Bliesma and Volt for high-quality-high-SPL applications?
(Of course dispersion/radiation will be narrower with the larger 5" cone in the passband - but i see this first as a property, not a drawback.)
I'd have to say no, simple due to the larger VC and higher base sensitivity, including the cleaner off axis performance and better transient response from lower Mms.
there is no such thing. Mms factors into the sensitivity and TSPs. that is it.
I'm back again! With more data for everyone to feast their eyes on.
First of all, getting an accurate measurement 1w @ 1m is real pain.
I had two calibrated dmms hooked up. One reading voltage, one reading amperage. Then I ran a 1000hz sine wave until the wattage x amperage = 1w
On top of this, I measured another speaker in tandem with the PMC dome. An SB Acoustics poly cone 5" 8 ohm speaker. Similar frequency range, same impedence, and I know the sensitivity of these are spot on with their published graphs since everyone and their mother has measured an SB Acoustics woofer.
So, what do we have?
They play loud as hell. This is the PMC dome at 1 watt.
Just for reference, this is the poly at the same watt, no change, same everything, in the same board
Ignore the purple circle, I'm not going to explain why, just ignore it.
The most accurate area of measurement we have is the red line, that is the easiest to compare
And with their published data
Yayyyy, accurate.
So, idk, its like a 90-93 db sensitivity.
We start to increase the volume and it stays pretty nice for a bit
97 DB
103db
106db
It didn't like 106 db so I didn't play it any louder than that.
At 103db though it was playing just fine with very low 3rd order distortion. I'll take higher 2nd order distortion over high 3rd order allllllll day long.
Anyways, thats my new data. I tried my best to get accurate data.
First of all, getting an accurate measurement 1w @ 1m is real pain.
I had two calibrated dmms hooked up. One reading voltage, one reading amperage. Then I ran a 1000hz sine wave until the wattage x amperage = 1w
On top of this, I measured another speaker in tandem with the PMC dome. An SB Acoustics poly cone 5" 8 ohm speaker. Similar frequency range, same impedence, and I know the sensitivity of these are spot on with their published graphs since everyone and their mother has measured an SB Acoustics woofer.
So, what do we have?
They play loud as hell. This is the PMC dome at 1 watt.
Just for reference, this is the poly at the same watt, no change, same everything, in the same board
Ignore the purple circle, I'm not going to explain why, just ignore it.
The most accurate area of measurement we have is the red line, that is the easiest to compare
And with their published data
Yayyyy, accurate.
So, idk, its like a 90-93 db sensitivity.
We start to increase the volume and it stays pretty nice for a bit
97 DB
103db
106db
It didn't like 106 db so I didn't play it any louder than that.
At 103db though it was playing just fine with very low 3rd order distortion. I'll take higher 2nd order distortion over high 3rd order allllllll day long.
Anyways, thats my new data. I tried my best to get accurate data.
Attachments
In the same frequency range, lower Mms CAN and usually will improve transient response. Of course other factors will influence it, but there is a direct correlation. One generalization isn't necessarily explainable with another.
@Bmsluite, the voltage is what is important, not the wattage. Using 2.83V is the standard measurement where all drivers are equal and then can be used together without doing the math to use wattage and make differing impedance drivers equal. That said, this is only if you want to verify the voltage sensitivity.
Otherwise, using an arbitrary voltage at a moderate output is good enough for xover modeling as long as the same voltage is used for all drivers. Just don't move the mic setup or volume knob.
Otherwise, using an arbitrary voltage at a moderate output is good enough for xover modeling as long as the same voltage is used for all drivers. Just don't move the mic setup or volume knob.
That's why I asked ... 😎
These measurements look way more realistic - what filter did you use for the midrange during the measurements? Did you start the sweep at 100Hz? MAybe try to start at 400-500Hz for high levels, you surely overdrive it otherwise.
Frequency response reminds my of the Dayton 2" which also play low but depending on the THD you accept you need to cross over higher.
Yup, 100 Hz, and yes, it did overdrive it for a couple seconds on the final sweep. Was not happy and I could hear it. Only driver I have actually ever killed was a ribbon tweeter though. About half a second with full signal was all it took to kink that ribbon.
I did run it at 2.83v originally. That's more than 1w when calculated with the amperage. It's around 96 db sensitivity at that voltage.
I did vaguely remember reading about this one but I couldn't remember anymore where it was installed actually. They used a JBL 2445 driver backwards as a dome midrange. In this PDF you can find some details of the system:
https://images.app.goo.gl/rqLFDXTpeGQVqGnR7
Regards
Charles
Seems like its a 6 ohm? I don't think there are any real 8 ohm drivers. Its an impedence curve right? So its just sort of like around an 8 ohm driver?
What part of the curve are we basing the metric on? 50 hz? Then its 4 ohm. 350hz? Then its 13 ohm. 1 khz? 5 ohm, 5khz? Then its 8 ohm.
If its DC resistance its 4.6 ohm though most 4 ohm drivers I have tested ohm out to below 4. Granted, most of those are subwoofers.
