Thats not entirely true. There are some very good 6.5s which don't get rough up top. Higher internally dampened cone materials can get around the issue and sound very good in the process. The new U18RNX Seas drivers are like this. The Seas Bragi kit I posted a link for uses them and sounds very good for all sorts of music. It's a good example of how a larger driver can be used higher up and defy the rules of MTM design. It also plays at very high levels without significant strain, especially with subs. The Audax HM170C0 and HM210C0 are also 2 great candidates. For larger MTMs. The HM210C0s combined with the Seas T35C002 in a WG plays at blistering levels. Enough to cause permanent hearing damage in one listening session, but the total distortion levels are a good bit lower than 1% at well over 100 dB.
Regarding a TMMW or TMMWW architecture, I can see this working if the lower mid is rolled off at a lower frequency, in the same style as a 2.5 way speaker. Imagine a 1" dome and a pair of 4" cones, and a 12" woofer or perhaps a pair of 10" woofers... The two 4" drivers work together down to the woofer crossover frequency, for instance 300 Hz. The two drivers will have a reasonable sensitivity and SPL capability. Somewhere around 600 - 1000 Hz, the lower of the 4" cones is rolled off at 6 dB/octave, leaving the upper 4" to meet the tweeter in the 2.5k -3.5k region. Would this be an improvement over a single 6" driver? It all depends on the drivers involved, and how low the tweeter can go. Most of the time, I suspect that the right 6" would get the job done better than a pair of 4" drivers, but if the designer has fallen in love with a particular tweeter that needs a 3.5k crossover, the 4" might be a better match.
Well, best 3" must be crossed over 3k to 4K hz. there is few chance but designer choice to have a deep most 4" can be flat (there are but look at til 45° roll off ; i.e. if worrying of the off axis dive above that frontier)
There is few chance most of the 6" are really handy at 2000 hz since baffled but particular designer choice (recess?) ; but well there are some till 2K flat 30/45° off axis
I assume a very good designer can mitige/trade off that by designing according the sweet spot distance and the room, we are more here in the DIY or the haute couture (designed according your size). Some want flat,some want BBC deep beginning there, you never know where will be the sweet spot but if designing for your room, etc.
Anyway having a ScanSpak good 3" (SS 10F8424G00) , the ideal cut off where it is flat off axis up to 3k/3k5 max if interrested by off axis behavior. Up to 4k is ok.
I expect most of the 4" will needs bit more overlapp to climb up to such cut-off with confort off-axis (i.e. : first or second order max). It is certainly feasible with such good 3" to 4" very wide flat (but physic, i.e. size of the cone is stubborn) and strong tweeter in the low (Morel, Dynaudio, 1.1/4" dome ?).
There is few chance most of the 6" are really handy at 2000 hz since baffled but particular designer choice (recess?) ; but well there are some till 2K flat 30/45° off axis
I assume a very good designer can mitige/trade off that by designing according the sweet spot distance and the room, we are more here in the DIY or the haute couture (designed according your size). Some want flat,some want BBC deep beginning there, you never know where will be the sweet spot but if designing for your room, etc.
Anyway having a ScanSpak good 3" (SS 10F8424G00) , the ideal cut off where it is flat off axis up to 3k/3k5 max if interrested by off axis behavior. Up to 4k is ok.
I expect most of the 4" will needs bit more overlapp to climb up to such cut-off with confort off-axis (i.e. : first or second order max). It is certainly feasible with such good 3" to 4" very wide flat (but physic, i.e. size of the cone is stubborn) and strong tweeter in the low (Morel, Dynaudio, 1.1/4" dome ?).
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Regarding 4-way speakers... In my opinion, there is no compelling technical reason why a high performance design must be a 4-way rather than a 3-way. Unless the designer wants it to be a 4-way.
Let me expand on that a bit. It is not difficult to find high performance, high SPL woofers which play well from 30 Hz up to 300 Hz... I am thinking about 12" to 15" drivers, or dual 10" drivers. At the upper end, there are many high performance tweeters which are comfortable playing down to 2k, either with or without waveguide. So the question is... can we find a midrange driver which can span from 300 to 2k? Obviously we can. This is what I meant when I said that there is no compelling technical reason why a high performance design must be a 4-way rather than a 3-way. I can't think of a technical performance spec or measure which could only be met with a 4 way, but not a 3-way.
So why might a designer choose a 4-way arrangement? One possibility is that they have chosen a particular driver(s) from the outset, and that driver choice forces them into a 4-way. Say they have decided on a particular 15" woofer in a 150 l vented box. Now perhaps they have fallen in love with a particular tweeter, one which runs best from 4k-up, then that would demand the mid driver cover a very large range, and it will likely be a small mid driver, which in turn would need a higher crossover from the mid to woofer. Or perhaps the designer has fallen in love with one of the dome midrange drivers (such as the Bliesma M74) that must be crossed over above 500 Hz. Now the designer is faced with the choice of trying to stretch the range of the 15" all the way up to 500-600 Hz, or splitting it into two bands. Given this scenario, a designer might be inclined to split the 30 Hz - 600 Hz range between the 15" driver and an 8" driver. The final possibility is that the designer simply wants to design a 4-way speaker.
Again, just my opinion... J.
If we expand idea of speakers to speaker system then one could arrive to a 4-way system also from room and size perspective. Subs around and then a stereo pair, which could be three way. Like hiding away the bass stuff and having mids and highs in plain sight.
Mkes sense if using subwoofers for the 2 first octaves as well as using open baffle drivers that have limited bandwidth due to the lack of load and own sizes.
I think matching or balancing the performance of each individual "Way" (W) in a multi way design is sometimes overlooked... Regardless of number of W the finished design is limited by the weakest link. ie I once heard a serious 4 way active system with twin 18 inch sub(s) per side up to 80 Hz, then twin 15 inch (per side) mid bass covering 80 Hz to 300 Hz, then a nice (expensive!) Scan Spk 6 inch mid-range covering 300 Hz to 1.5 K Hz, then a mega $$$ compression driver / horn for the top end.
At low SPL and with gentle "girl and guitar" type music it was beautiful, but, the system was still limited by the single 6 inch mid-range and had no hope of producing lifelike dynamics with almost any type of music... High SPL with low distortion was just not possible.
When he swapped the SS mid for a PHL 10 inch midrange ( https://en.toutlehautparleur.com/speaker-phl-audio-3861-8-ohm-10-inch.html ) the system was totally transformed beyond belief... Amazing performance and with true reference performance.
At low SPL and with gentle "girl and guitar" type music it was beautiful, but, the system was still limited by the single 6 inch mid-range and had no hope of producing lifelike dynamics with almost any type of music... High SPL with low distortion was just not possible.
When he swapped the SS mid for a PHL 10 inch midrange ( https://en.toutlehautparleur.com/speaker-phl-audio-3861-8-ohm-10-inch.html ) the system was totally transformed beyond belief... Amazing performance and with true reference performance.
PS
When I say "lifelike" dynamics I mean a system which can recreate the experience of a piano being played in your room ie from "PPP" to "fff" (https://en.wikipedia.org/wiki/Dynamics_(music)... Real instruments are loud... 130dB peaks when miking a piano... In room thats around 112dB to 115 dB at 2 to 3 meters.
https://www.dpamicrophones.com/search-results?searchtext=HOW TO MIC A GRAND PIANO
When I say "lifelike" dynamics I mean a system which can recreate the experience of a piano being played in your room ie from "PPP" to "fff" (https://en.wikipedia.org/wiki/Dynamics_(music)... Real instruments are loud... 130dB peaks when miking a piano... In room thats around 112dB to 115 dB at 2 to 3 meters.
https://www.dpamicrophones.com/search-results?searchtext=HOW TO MIC A GRAND PIANO
imo the only reason one would use such setup like Wilson Audio is for status (more drivers = more sales) and/or max spl. I've heard the system mentioned and one could sometimes hear the individual drivers due to the gigantic distance between drivers. I also saw some measurements later in a magazine which show extreme lobing at even 10 degrees of axis, something that is also easily confirmd by simulation. To me a big no-no.
Nobody listens to acoustical insturments which are being played at full dynamics from 3 meters distance, as someone who grew up with a brother playing drums (one of the loudest instrument on your site https://www.dpamicrophones.com/mic-university/acoustical-characteristics-of-musical-instruments) and having listened to live piano's. If you look at pictures of orchestra this is also easily confirmd with people sitting easily 10+ meters from the instruments. You literally become deaf listening to the loudest instruments so close, which is also very uncomfortable, listening to drums being played at such volume literally hurts your ears. Making such comparison also makes no sense as most of the music which contains such instruments have compression on it which means it is even supposed to be played so loud in the first place.
This is just absurd to me, a 6 inch scanspeak acording to the specsheet and a quick simulation could probably hit 106db (maybe even higher) that is plenty for in home usage. I've once measured my own speakers while playing music at what I consider high level with a db meter and phone and came around 76 db with peaks not much higher. Around that level it already becomes difficult to talk to other people without standing next to them (which most people I have over find uncomfortable and prefer to have it lower). I play all types of music from big orchestra to edm and literally have never had the impression that it only sounds good with basic music. That is playing with two 8 inch woofers in sealed enclosures, no compression drivers. That is even playing in a 6x7 meter room sitting 4 meters from the speakers, which I learned looking at forums is rather big for european standards, still no moving cones or excessive distortion or anything. I just cannot fathom listening much much louder most definitely not needing 30db more. Obviously there is a case to be made for speakers which have 5/6 inch bass drivers or smaller, yes those are indeed compromised but not a 6 inch woofer in a 4 way which contains 2x 18 inch subwoofers, maybe he had an even bigger room but I've yet to see (and be in) rooms which are substantially bigger...
Nobody listens to acoustical insturments which are being played at full dynamics from 3 meters distance, as someone who grew up with a brother playing drums (one of the loudest instrument on your site https://www.dpamicrophones.com/mic-university/acoustical-characteristics-of-musical-instruments) and having listened to live piano's. If you look at pictures of orchestra this is also easily confirmd with people sitting easily 10+ meters from the instruments. You literally become deaf listening to the loudest instruments so close, which is also very uncomfortable, listening to drums being played at such volume literally hurts your ears. Making such comparison also makes no sense as most of the music which contains such instruments have compression on it which means it is even supposed to be played so loud in the first place.
Except musicians... The pianist is exposed to the full dynamics of the instrument, and if it is a 6' grand or bigger, that is some serious SPL. Drums, horns, sax, not to mention electric guitar and other modern amplified instruments. Opera singers performing next to each other on stage are subjecting each other to 110 dB SPL... I have found musicians tend to like their music about 10 dB louder than sane people do...
Hi, jeah home listening levels are usually quite modest with SPL meter.
Here is interesting thing though, just this past weekend had a chance to listen a hifi setup. The space was kinda big and about ten people present to listen to music and see the hifi setup. It was surprisingly distorting setup, don't know why, turntable or amp or the speaker or gain staging or sometging so popped up mobile app SPL meter. Around 80db it was about 2m away. Usually below like you describe, high 70s. Nice loud listening level, except it was too loud for the system, had a feeling the system would have sounded better if turned down, bit annoying sound although with SPL meter it wasn't that loud. Not smallest speaker, three way with few 10" woofers, but as said not sure what was distorting.
Then went on to a live show about an hour later. Four piece jazz band acoustically and a singer with small pa backing for the vocals. No surprise levels were about the same with the phone app SPL meter, bit below 80db some times poking above, quite similar as with the hifi setup. This was where I sat, quite close to band, some seats would have been louder some quieter. Nice listening level and no hint of distortion, no hint of listening fatigue, could have been louder and still enjoyable. Easy conversation unlike in the hifi occasion.
While 130db might be excessive most of the time the nice comfortable high listening level distortion free nice loud listening level is not easy task. I've built some speakers during the years and current setup is by far the most fun at this loud listening level. Three way with 15". 5" fullrange driver speaker I started with sounded good in hifi sense and was specked 80+db/w/1m sensitivity, but it just couldn't do the nice high listening level.
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+1 on the "Fun starts at a single 15" per side and up".
It's not about max SPL (though that is fun whenever one gets in a certain mood), it's about the speaker being able to push/couple with the air more effectively.
It's not about max SPL (though that is fun whenever one gets in a certain mood), it's about the speaker being able to push/couple with the air more effectively.
Yeah something like that, there is no comparison between big and small system. Not sure what it is, probably multiple things that start to annoy the ear with the smaller systems. Perhaps some top performer with modern drivers could work fine. Personal experience so far is that even seemingly modest ~80db at listening spot, the comfortable high listening level, is not easy task to play cleanly 🙂
Does the center to center between the two mids matters in a MTM, or one should only matter of the CtC of the mids with the tweeter only ?
In the first case the MMT is winner and in the second case the MTM is a winner. Which matters most to avoid comb filtering effect in the vertical plane ?
I also remember Proac was offsetting the two mids in some venerable designs like the 2.5 ... some others used to offset only the tweeter to make the two mids distance closer...
Do you think it is manageable with sim in tools like Vituix ?
In the first case the MMT is winner and in the second case the MTM is a winner. Which matters most to avoid comb filtering effect in the vertical plane ?
I also remember Proac was offsetting the two mids in some venerable designs like the 2.5 ... some others used to offset only the tweeter to make the two mids distance closer...
Do you think it is manageable with sim in tools like Vituix ?
/subjective_opinion
If you're asking me then I'd say that using mids with such little difference is utter hogwash, perhaps better to have a smaller mid/tweet and use a supertweeter up high instead, with the multiple mid sizes you run into more problems trying to incorporate pointless and difficult crossover filters and gain absolutely nothing except make the design more expensive.
The distance between all the drivers matter, you get some artifacts pending on angle and distance measured not matter how good the implementation is.
Want higher sensitivity? Use the right drivers for the job and drop the glorified marketing BS.
Some people buy crap like this blinded by marketing saying that 5-6-7-8-9way speakers are the "absolute must", not necessarily the same crowd as the people getting the highest watt rating.
/subjective_opinion
If you're asking me then I'd say that using mids with such little difference is utter hogwash, perhaps better to have a smaller mid/tweet and use a supertweeter up high instead, with the multiple mid sizes you run into more problems trying to incorporate pointless and difficult crossover filters and gain absolutely nothing except make the design more expensive.
The distance between all the drivers matter, you get some artifacts pending on angle and distance measured not matter how good the implementation is.
Want higher sensitivity? Use the right drivers for the job and drop the glorified marketing BS.
Some people buy crap like this blinded by marketing saying that 5-6-7-8-9way speakers are the "absolute must", not necessarily the same crowd as the people getting the highest watt rating.
/subjective_opinion
discussion, if any interrests, should be splitted in two : two identical mids and two different sized mids.
Most of the time we should land in the MMT vs MTM discussion with identical mid staying in the 2.5 ways or 3 ways startegy.
Most of the time we should land in the MMT vs MTM discussion with identical mid staying in the 2.5 ways or 3 ways startegy.
The original poster showed a four way speaker. Centre distance may not even have been an issue. Small bandwidth was probably the question to answer.