I am trying to choose the right midrange driver for my project. The driver will have to be capable of at least 110db/1m peaks Without audible distortion or compression. The passband will be around 300Hz to 2500Hz with up to 6th order filters.
For example the SB12MNRX2 will in theory be able to do this driven with around 100w, and crossed the 300 Hz the excursion shouldn't be an issue. Max Power handling is 100w, so that should also be okay.
Can I be confident that this driver will do the trick, or is it something else I should consider?
For example the SB12MNRX2 will in theory be able to do this driven with around 100w, and crossed the 300 Hz the excursion shouldn't be an issue. Max Power handling is 100w, so that should also be okay.
Can I be confident that this driver will do the trick, or is it something else I should consider?
If your finished speaker is going to be flush mounted in a wall, then you can assume 2 pi radiation for the whole frequency range of the midrange driver.
If not, then you must assume that the lower region will be 4 pi radiation. In other words, you will need baffle step compensation. Depending on cabinet width, the transition to 2 pi radiation could be anywhere from 400 Hz (very wide baffle) to 1200 Hz (very narrow baffle).
Most driver manufacturers (including SBA) use a standardized baffle to measure their drivers. This is a large, wide baffle which simulates 2 pi radiation.
When we install a driver like the SB12MNRX2 in a typical baffle, we will get the advertised 90 dB @ 2.83V/M from 1000 Hz up. Below 1000 Hz, the output will taper off until it is reduced by a full 6 dB somewhere around 100 Hz.
So this is something else to consider and think about.
If not, then you must assume that the lower region will be 4 pi radiation. In other words, you will need baffle step compensation. Depending on cabinet width, the transition to 2 pi radiation could be anywhere from 400 Hz (very wide baffle) to 1200 Hz (very narrow baffle).
Most driver manufacturers (including SBA) use a standardized baffle to measure their drivers. This is a large, wide baffle which simulates 2 pi radiation.
When we install a driver like the SB12MNRX2 in a typical baffle, we will get the advertised 90 dB @ 2.83V/M from 1000 Hz up. Below 1000 Hz, the output will taper off until it is reduced by a full 6 dB somewhere around 100 Hz.
So this is something else to consider and think about.
First, if you want to achieve peaks of 110dB without distortion or compression then you need headroom above and beyond that.
Second, the spec sheet lists its rated power handling at 50W, not 100W.
Third, according to Unibox, 100W will only get you 106dB/1m - 250W will get you 110dB/1m. 50W gets you 103dB/1m. But if the 2nd speaker is playing the same thing (and that's a big "if"), you'll gain an extra 6dB. But if you lose 6dB to baffle step as noted above, you're back where you started.
However, since you are talking about a midrange, we can assume a 3-way so it's likely the baffle width necessary to accommodate the larger woofers will be large enough to bring the baffle step loss frequency low enough to not be a factor with this driver. If it is, I'd raise the xo point as needed. Actually with a 4" mid, I'd probably raise the xo point a little anyways.
One might worry instead about having to pad the mid down to match the woofer level since it/they will suffer baffle step loss and so you would need even more power to get the mid up to the desired SPL's (because of wasted energy), but it sounds like you are going to go active so it may not be a factor.
For effortless dynamics, you should use a bigger mid or multiples of smaller ones. Or adjust your design criteria so that you remove the potential to damage your hearing so badly.
Second, the spec sheet lists its rated power handling at 50W, not 100W.
Third, according to Unibox, 100W will only get you 106dB/1m - 250W will get you 110dB/1m. 50W gets you 103dB/1m. But if the 2nd speaker is playing the same thing (and that's a big "if"), you'll gain an extra 6dB. But if you lose 6dB to baffle step as noted above, you're back where you started.
However, since you are talking about a midrange, we can assume a 3-way so it's likely the baffle width necessary to accommodate the larger woofers will be large enough to bring the baffle step loss frequency low enough to not be a factor with this driver. If it is, I'd raise the xo point as needed. Actually with a 4" mid, I'd probably raise the xo point a little anyways.
One might worry instead about having to pad the mid down to match the woofer level since it/they will suffer baffle step loss and so you would need even more power to get the mid up to the desired SPL's (because of wasted energy), but it sounds like you are going to go active so it may not be a factor.
For effortless dynamics, you should use a bigger mid or multiples of smaller ones. Or adjust your design criteria so that you remove the potential to damage your hearing so badly.
Hi, one more factor in the specs that needs noting.
Sensitivity of 90.5 dB is given for 2.83v/1m.
Since it is a 4 ohm driver, that is a 2 watt sensitivity, not 1 watt like it would be for an 8 ohm driver.
So call it 87.5 dB, 1 w.
Using the 50 watt power rating, spl works out to be 104.5 dB....and that's assuming no compression, acceptable distortion, etc
I'd definitely consider something else if i wanted clean 110dB peaks.
Sensitivity of 90.5 dB is given for 2.83v/1m.
Since it is a 4 ohm driver, that is a 2 watt sensitivity, not 1 watt like it would be for an 8 ohm driver.
So call it 87.5 dB, 1 w.
Using the 50 watt power rating, spl works out to be 104.5 dB....and that's assuming no compression, acceptable distortion, etc
I'd definitely consider something else if i wanted clean 110dB peaks.
Another consideration is the crossover. If not at least second order electrical the driver will be driven too hard at lower frequencies, and even that isn’t probably enough. IMHO you need at least twice the Volume Displacement (you now have 11 cm3) to produce this kind of SPL.
Thank you for all your answers. The design goal is that I can continue to play movies at a few db below reference levels. A requirement is that each speaker can output 105db peaks at listening position. I won't be anywhere near that continuously obviously.
Is the rated nominal power handling what I should be looking at when talking about peaks?
In theory then, Scanspeak 15M/4624 should have a higher output capability and be more suited to my needs. But I kind of wanted smaller diameter driver, So that it can be crossed at 2500Hz without a dip in the polar response.
The baffle is 450mm wide and it will be crossed to a 15PR400 actively.
Is the rated nominal power handling what I should be looking at when talking about peaks?
In theory then, Scanspeak 15M/4624 should have a higher output capability and be more suited to my needs. But I kind of wanted smaller diameter driver, So that it can be crossed at 2500Hz without a dip in the polar response.
The baffle is 450mm wide and it will be crossed to a 15PR400 actively.
Go MTM up top. Even if you you have to wire 4ohm drivers in series (so no 6dB gain), you increase the max SPL.
2500Hz xo is possible for many 5" drivers. Check the off-axis response for each specific candidate.
Maybe look at some pro mids too.
2500Hz xo is possible for many 5" drivers. Check the off-axis response for each specific candidate.
Maybe look at some pro mids too.
Since this is an actively processed system, I'd not worry at all about baffle diffraction step.
FWIW the 15PR400 can be run up quite high if need be. Quite a good driver IMO.
FWIW the 15PR400 can be run up quite high if need be. Quite a good driver IMO.
I need a matching centre speaker under the tv, so a MTM will be too tall.
So i need a single 4-5" driver that can handle up to 110db peaks 300-2500Hz. I could push it to 400Hz if that helps.
What about the Satori drivers? Can they handle the amount of power required to get them there?
So i need a single 4-5" driver that can handle up to 110db peaks 300-2500Hz. I could push it to 400Hz if that helps.
What about the Satori drivers? Can they handle the amount of power required to get them there?
I think you need something like that:
B&C Speakers
That 6-7dB more efficiency is a lot and you don't need the low frequency extension of the mentioned SB driver anyway.
B&C Speakers
That 6-7dB more efficiency is a lot and you don't need the low frequency extension of the mentioned SB driver anyway.
+1
Have a good look at what B&C, BMS and Faital Pro have to offer.
Or following your SBA lead this driver might do the job: SB Audience :: NERO-6MRN150D
Last edited:
Hmm, ~[300*2500]^0.5 = ~866 Hz mean = ~34400/pi/866 = ~12.65 cm dia. = ~ 6.5" frame and all the [few] prosound versions I found all peaked out at around 104-105 dB/2 pi, so good luck finding a small driver solution.
Don't know about Satori, assumed prosound would be loudest at low distortion based on larger frame size performances.
GM
Don't know about Satori, assumed prosound would be loudest at low distortion based on larger frame size performances.
GM
Will the fidelity at lower volumes take a hit with this driver compared to a typical "hifi" midrange? I notice a rather high mms and a slightly ragged impedance-curve.
I have to again emphasise that the 110db/1m requirement is for transients only, i am never anywhere near those kinds of SPL's sustained. I just want to know that the system can handle peaks well.
Each driver will have around 100Wrms available at 8 ohms, probably quite a bit more peak power. I just don't know how to tell whether a driver can handle the peak loads. Nominal power is rated for a sustained load.
Interesting! Powerful little bugger! More horn driver than point source, so meets your needs to spare once EQ'd flat due to the need for a ~0.7 Qtc to handle the 50+W to reach 110 dB/2500 Hz.
GM
GM
IME, yes, due to its 'buckboard wagon' stiff suspension a horn driver needs to counteract the horn's huge air mass 'plug' and/or to handle high power transients ~continuously.
GM
I think I will have to lower the requirements. It seems that there is a consensus that a 4-5" hifi midrange driver will not be able to hit those 110db/1m peaks. Sound quality is more important than the ultimate volume, so I'd rather not go pro sound midrange driver.
Scanspeak 15M/4624G seems to be one of the hifi midrange drivers with highest theoretical output potential that I can find. Any other candidates?
Scanspeak 15M/4624G seems to be one of the hifi midrange drivers with highest theoretical output potential that I can find. Any other candidates?
So you say "sound quality" is not good with pro sound drivers? I don't think that's true. Of course there are pro drivers that are not so good for home hifi, but there are home hifi drivers that are not so good for that task either.
But for very high SPL, there are only few home hifi drivers that are up to the task, and these are not the smaller ones that you are after, imo.
But for very high SPL, there are only few home hifi drivers that are up to the task, and these are not the smaller ones that you are after, imo.
I got the impression from GM that pro sound midrange drivers tend to have a stiff suspension, Which causes problems at lower volumes.Maybe I misunderstood.
Do you have any specific drivers to recommend? Either pro sound suitable for home hifi, or home hifi drivers with good output capabilities.
I think GM mentioned the stiff suspension as an advantage, you don't need a loose suspension if you don't want deep bass from small drivers.
Generally speaking look for smooth frequency and clean CSD (waterfall) pass-band response. Below is the mentioned 5" B&C driver analysis, plus two larger. Very good and clean responses, with very low harmonic distortion and high power handling.
Btw if you ask me, for a 3 way high SPL home speaker, i would choose a 6.5 or 8 inch pro mid for the 15PR400 and an 1 inch CD + waveguide. With the waveguide properly crossed, you don't need to worry about uneven off-axis response that you wanted to avoid with the small mid. If you choose carefully, you don't want to go back to the usual home hifi drivers imo.
Check out these superb drivers:
B&C SPEAKERS 5MDN38-8 (Mid-range 5", 8 Ohm, 200 Wmax)
B&C Speakers 6MBX44 MBX Mid-Bass Woofer | audioXpress
Test Bench: B&C Speaker 8MBX51 Midbass Woofer | audioXpress
Generally speaking look for smooth frequency and clean CSD (waterfall) pass-band response. Below is the mentioned 5" B&C driver analysis, plus two larger. Very good and clean responses, with very low harmonic distortion and high power handling.
Btw if you ask me, for a 3 way high SPL home speaker, i would choose a 6.5 or 8 inch pro mid for the 15PR400 and an 1 inch CD + waveguide. With the waveguide properly crossed, you don't need to worry about uneven off-axis response that you wanted to avoid with the small mid. If you choose carefully, you don't want to go back to the usual home hifi drivers imo.
Check out these superb drivers:
B&C SPEAKERS 5MDN38-8 (Mid-range 5", 8 Ohm, 200 Wmax)
B&C Speakers 6MBX44 MBX Mid-Bass Woofer | audioXpress
Test Bench: B&C Speaker 8MBX51 Midbass Woofer | audioXpress