I played with exactly that driver, together with a Seas DXT in a narrow baffle - works great and smoothly
Now play with the MW13TX from SB... I find it better in every way - but it is also more expensive... so... it fits the cost/performance balance nicely.RS125 is still a very fine little driver and cheap. I did not hear the big difference before comparing i directly, so one should be very happy with either.
I once did a comparo where I changed woofers out in a small 2-way (and readjusted crossover filters via DSP) and compared the Scanspeak Discovery 15W, Peerless Nomex, SB15 paper and poly, RS150P, and Zaph ZA14. My favorite was the ZA14. It was as musical and clear as the Scanspeak, but virtually zero distortion all the way until the cone bottomed out. Just a very clean and well-behaved driver. Primary drawback for me was little bass compared to the others. Given the high Q breakup up @10khz, it could be easily notched via Lars from Purifi method to remove both the linear and non-linear distortion and crossed fairly high (my comparo was limited to 2.3khz).
I still fail to see why such an 'off the shelf'-product from Asia can compete nicely with the big brands at considerably lower cost (be it here in Europe they are not that affordable). But it does deliver. John Krutke knew what he was doing, obviously. For us it's sad he went for racing instead of DIY loudspeakers.
Which one ? You talk about the W or te M line ? The woof line is going low indeed, but not a pure midrange (btw not sure why a mid will play better than a good woofer, because of his lesser Xmax, less long voice coil ?
You have played with the SB cac or Nbac iirc, how they compete with the Revelator please ?
If the op is active so can notch easily, the wavecore are maybe the half way between the SB and the SS ?!
I like to work backwards.
What frequency do I want to cover?
What SPL do I need to reach? eg. background listening, hi-fi listening, live-levels, outdoor live levels and venue size
What dispersion do I need eg. @60 degrees - flat, or accept 3dB, or 6dB down
Then I choose the driver. Why fix on 5" first. Is there a pre-existing hole that needs to be covered?
What frequency do I want to cover?
What SPL do I need to reach? eg. background listening, hi-fi listening, live-levels, outdoor live levels and venue size
What dispersion do I need eg. @60 degrees - flat, or accept 3dB, or 6dB down
Then I choose the driver. Why fix on 5" first. Is there a pre-existing hole that needs to be covered?
^^^
So the biggest driver eg. 8-10" midrange will have the highest SPL or lowest distortion (tend to go hand in hand)
the smallest driver eg. 2-4" but won't go as loud or have the best distortion but will have the best dispersion eg. flat to 2Khz on-axis all the way to 60 degrees off axis.
It's up to the designer to pick the trade-offs, IMHO
5-6" is a common trade-off for balance, it seems.
So the biggest driver eg. 8-10" midrange will have the highest SPL or lowest distortion (tend to go hand in hand)
the smallest driver eg. 2-4" but won't go as loud or have the best distortion but will have the best dispersion eg. flat to 2Khz on-axis all the way to 60 degrees off axis.
It's up to the designer to pick the trade-offs, IMHO
5-6" is a common trade-off for balance, it seems.
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how about the ScanSpeak 15wu (expensive $$$$$)
Smaller (4")
4" Peerless 830870 (cheaper $), 830855, 830854, 830881, 830872 etc
https://ampslab.com/blog/2018/05/20/peerless-830870/
https://ampslab.com/blog/2019/11/01/solitaire-2/
Different Peerless 4" Peerless 830872
https://www.rob-elder.com/LouC/speakers/Buyout/BravoxTower.html
https://ampslab.com/blog/2020/08/27/scanspeak-illuminator-15wu/
https://ampslab.com/blog/2020/08/31/enlightenment/Smaller (4")
4" Peerless 830870 (cheaper $), 830855, 830854, 830881, 830872 etc
https://ampslab.com/blog/2018/05/20/peerless-830870/
https://ampslab.com/blog/2019/11/01/solitaire-2/
Different Peerless 4" Peerless 830872
https://www.rob-elder.com/LouC/speakers/Buyout/BravoxTower.html
While most people opt for the smallest midrange driver available to achieve the goals of their design, I've recently started to approach things differently. Nowadays, I look for the largest diameter driver I can get away with and make sure the HF driver can cope with the playback levels I expect at the HP frequency needed. IOW, I start with the mid driver and look for a suitable HF driver, not the other way around.
Trying to get a 3-ish inch midrange to play realistically loud (around 100+ dB) above 250 or so Hz isn't going to happen with a second order HP. IM distortion goes through the roof and is in my opinion one of the most negatively audible forms of distortion. If you think 100-ish dB is alot, listen to some better piano and vocal recordings with appreciable dynamic range. You'll hit the limit quicker than you think and the speaker falls apart trying to play the low mids. Even a solo cello at its live (unreinforced) reference playback level will push a good 3 way design to its limits with its strong concentration of low-midrange energy content. Going higher on the mid HP doesn't make sense due to the transition from omni to directional radiation right around that frequency, making power response suffer. There are a few larger LF drivers that can cope with a higher HP, but then you have the issue with putting more back radiated midrange energy into the enclosure which will need to be dampened and controlled - not an easy task if you've tried it yourself, especially on a ported type enclosure.
Bottom line here is - once you've heard midrange from a really good, larger mid or midbass driver, you'll understand what I'm talking about. There is much more acoustical information concentrated in the mid frequency range itself and that is IMO the most important area to focus on when designing a speaker, rather than picking the HF driver (or dedicated LF in a 3 way) first. Yes, LF and HF are also very important (I'm not intending to design a speaker to listen to AM radio - lol), but they're not as critical to get right as the mids themselves. Balancing and blending driver outputs as a system is much more important than obsessing with all out distortion figures of the individual drivers. Also, you can learn alot from a cone driver by just running it free air at low levels playing full range music through it right in front of your face. Its my preferred method of auditioning cone drivers and has never failed to expose a driver's true character.
That being said, I love the cheaper vifa/peerless NE line of drivers ie. NE149W and NE180W (no slit cone as with revelator). The slit cone drivers sound weird to me in the upper mids. I don't care much for the larger Seas paper cone drivers either, as they sound rough to my ears in the upper mids as well.
There are a few higher sensitivity, larger pro mid drivers that I'd consider as well, like the B&C 8PE21 (high SPL), 8NDL51 (amazing low 90s dB/W midbass) along with the lowly Eminence Beta 8A (very good CHEAP all around large mid or even bass mid). I've run the Beta 8A and also 8NDL51 in a 2 way with a modded Audax TW034 and with Seas T35-C002, both in a WG with very good results. The SB Acoustics Rosso 6MW150D is another great low 90s dB/W 6 inch driver which looks really promising.
Trying to get a 3-ish inch midrange to play realistically loud (around 100+ dB) above 250 or so Hz isn't going to happen with a second order HP. IM distortion goes through the roof and is in my opinion one of the most negatively audible forms of distortion. If you think 100-ish dB is alot, listen to some better piano and vocal recordings with appreciable dynamic range. You'll hit the limit quicker than you think and the speaker falls apart trying to play the low mids. Even a solo cello at its live (unreinforced) reference playback level will push a good 3 way design to its limits with its strong concentration of low-midrange energy content. Going higher on the mid HP doesn't make sense due to the transition from omni to directional radiation right around that frequency, making power response suffer. There are a few larger LF drivers that can cope with a higher HP, but then you have the issue with putting more back radiated midrange energy into the enclosure which will need to be dampened and controlled - not an easy task if you've tried it yourself, especially on a ported type enclosure.
Bottom line here is - once you've heard midrange from a really good, larger mid or midbass driver, you'll understand what I'm talking about. There is much more acoustical information concentrated in the mid frequency range itself and that is IMO the most important area to focus on when designing a speaker, rather than picking the HF driver (or dedicated LF in a 3 way) first. Yes, LF and HF are also very important (I'm not intending to design a speaker to listen to AM radio - lol), but they're not as critical to get right as the mids themselves. Balancing and blending driver outputs as a system is much more important than obsessing with all out distortion figures of the individual drivers. Also, you can learn alot from a cone driver by just running it free air at low levels playing full range music through it right in front of your face. Its my preferred method of auditioning cone drivers and has never failed to expose a driver's true character.
That being said, I love the cheaper vifa/peerless NE line of drivers ie. NE149W and NE180W (no slit cone as with revelator). The slit cone drivers sound weird to me in the upper mids. I don't care much for the larger Seas paper cone drivers either, as they sound rough to my ears in the upper mids as well.
There are a few higher sensitivity, larger pro mid drivers that I'd consider as well, like the B&C 8PE21 (high SPL), 8NDL51 (amazing low 90s dB/W midbass) along with the lowly Eminence Beta 8A (very good CHEAP all around large mid or even bass mid). I've run the Beta 8A and also 8NDL51 in a 2 way with a modded Audax TW034 and with Seas T35-C002, both in a WG with very good results. The SB Acoustics Rosso 6MW150D is another great low 90s dB/W 6 inch driver which looks really promising.
Many 6" and 8" with some efficienty will loose their flat off axis behavior after 2k hz. And also have not a good low end behavior...cut off needed at 500 hz or more for the PA drivers of this size...they are mids indeed not woofers. Hence you can use them on 2 octaves only.
Some want a larger widthband without loose the off axis behavior. At your required 100 db average level which is loud and gives a small dynamic peaks margin (+ 15/20 db) very few 3" are able to that level. You need MTM which works fine with 2x 5" to 3" drivers and permit this good off axis behavior in the highs and large bandwidth 3 octaves and more.
That said one can be happy with an Audax 6" 17pm0 driver usable between 500 hz to 2000 hz. But its soundstage will never approach a 5" or less in the highs towards the tweeter. Choose your poison.
Some want a larger widthband without loose the off axis behavior. At your required 100 db average level which is loud and gives a small dynamic peaks margin (+ 15/20 db) very few 3" are able to that level. You need MTM which works fine with 2x 5" to 3" drivers and permit this good off axis behavior in the highs and large bandwidth 3 octaves and more.
That said one can be happy with an Audax 6" 17pm0 driver usable between 500 hz to 2000 hz. But its soundstage will never approach a 5" or less in the highs towards the tweeter. Choose your poison.
If you work with passive filter you may want to push higher the cut off with the treble without compromise too much the vertical center to center spacing between the drivers. It can be reach with the small form factor tweeter that have a 5 to 6 cm diameter. Put it between two 3" in a MTM. Cut off at 4k hz or plus to acheive 1 to 1.2 wave length cut off spacing (c to c) then in the low end a cut off at circa 500 hz. Then you have the filters far enough where the ears are sensible, a soundstage to die for and enough upper bass and low midrange with the woofer of your choice.
One can made a narrow kef 104 ref design like that...never see that but the old mtm proac colomn...they even did not use woofer or went wmtmw as Dynaudio or Dunlavy...
One can made a narrow kef 104 ref design like that...never see that but the old mtm proac colomn...they even did not use woofer or went wmtmw as Dynaudio or Dunlavy...
I agree with you on the bandwidth issue. Thats why I like 4 way systems more these days. Splitting the mids up into separate ranges allows the use of a smaller driver so you can run a high xover and have good dispersion up there, plus it lets you position the driver closer to the HF source. The trick with a good 4 way is to use first order filters between LF and midbass drivers. Phase response is important at lower frequencies and our ears are very sensitive in this area, plus off axis response isn't an issue that far down into the low mids, so a first order filter is appropriate.
3 way front and subwoofers... so 4 way is my best option. I can't see myself living with a speaker where the off-axis response is not almost as good as the on-axis. Then I'd rather live with a few dB less and have a smooth response all over. Quality of sound rather than loudness. A 5" midrange in a fully active system - when it only works from around 500Hz to 2kHz.... plenty loud for me
