Very interesting way of saying dimensions. Can I take this that the lower band drivers have smaller diffraction problems even with the same size baffles? So they can be on the plain rectangular baffle and still have relatively small problems. I hope this holds good for midrange as well. Fewer cylinders, easier making.
I wish I could replace the faceplate of the tweeter or somehow mount it without one. The 21mm tweeter I want to use has a smaller faceplate than 30mm-ish tweeters', but still relatively larger. They have one with almost no faceplate area, but the FR curve isn't as good as the one I like.
If I use ATC or Volt, I guess not much to worry about thanks to the waveguides.
Hi, simple answer is yes you can, small square is roughly the same as small disk (end cap of a cylinder), but there is a lot of nyance to geek over
I hope I understood right what you refer to, single driver on it's own "box" or "cylinder". Quick example, If you put a 10cm diameter small mid driver on 10cm diameter round or rectangular baffle, difference between the two are the rectangular baffle has the corners "poke out", which are basically centimeter or two sized, in this case, and not side or above the driver but diagonal. Position is important, diagonal stuff isn't directly toward earliest room reflections so their effect is less important in that sense. Another, the corners are perhaps fifth of driver diameter, so quite close, short and small compared to sound wavelength that diffracts, so their effect is kind of small. In this sense circular and rectangular minimal baffle for single driver are pretty much interchangeable what the interference ripple due to edge diffraction is toward listening window. But, in a four way system the lowest way, say up to few hundred hertz has bandwidth on very long wavelengths so the structure can be bigger without issues.After all you'd want some volume inside the box to get sensitivity for bass.
Overall enclosure beyond the front edge has an effect as well, so perhaps cylinder and rectangular tubes have bit more difference. Rectangular could be wee bit less deep for same volume inside, but shorter back edge of tube might show less diffraction ripple from there. Also innards effect, some small differences there, how much "breathing room" immediately behind driver. Tube likely resonates and emits sound much less than flat panels. Either could be easier to build, depends what you have in your mind, plumbing pipe with wooden endcaps quite easy.
Substitute the 10cm with any diameter and this stuff holds true relative to wavelength.
That is one driver on isolation, but you are building a system. If all transducers are on their own baffless you now have multiple bafflesteps, although pretty close together. 8" woofer/baffle has it octave lower than 4", roughly around 1kHz and 2kHz in frequency. All these have their effect on system DI so you might want to do at least simple simulation how it might go together. They'd all require different EQ which is no issue with DSP. Modular approach is great, as you can experiment with things, easier to handle than big bulky objects, likely cheaper at least if mistakes happen. Hifijim has couple projects that considers structure size, shape and driver layout in terms of system DI. Others have as well, like wesayso, can't remember who else, likely many, but not as many as rectangular baffle/box builders
Look into waveguides. For example members augerpro and fluid, perhaps others, have posted retrofitter 3D printed ones for various dome tweeters and in various sizes. I like to think a waveguide makes transducer bigger thinking about the stuff with wavelength/size. Afterall it reduces flat baffle area, optimized shape instead of non-optimized
Tweeter is the most problematic one as there is no low pass filter and deserves proper structure. Woofers we low pass, and could do it below edge diffraction and other issues, like breakup and beaming. Have fun!
Last edited:
Taking the concept of waveguide further- it's almost like thinking of it as an "Air Cone" midrange with high fs, low mms, high efficiency, tiny Xmax and lots of HF extension. Not that different (until the extremes) from some of the classic underhung/low overhang lightweight midranges/fullranges, but without a big thin vibrating paper assembly, it's an air mass instead; with more controllable behavior than a lightweight 3d assembly but worse LF efficiency. No surprise that such an enhancement would work well to make a tweeter sound good lower in frequency.
Yes, it is encouraging to see tweeters with smallest faceplate possible or none. D3004 seems to be less than 40mm in diameter, much smaller than 60-75mm. Unfortunately, D2104 is over 90mm...
Proper waveguides (in "classical" term) are actually curved baffles, where the radius begins at the edge of the diaphragm.
But the best (tweeter or lower frequency) baffle is that which can provide the response we want. So there is no "one best" baffle for everyone, IMO.
Last edited:
I did a bit of homework on the candidate midhigh drivers for an easy comparison:
Please let me know what you think. Data of some drivers are sparse and maybe unreliable...
| Driver | Low crossover | High crossover | Sensitivity | Max Power(W) | Xmax(mm) | Price(USD) |
| ATC SCM75-150 | 300? | 2000? | 91? | 75 | 4 | 900? |
| Volt VM753 | 450 | 4000 | 92 | 100(AES) | 2 | 580 |
| Bliesma M74S-6 | 500 | 5000 | 95 | N/A?!?!? | 2.4 | 411 |
| HiVi DM-7500 | 300? | 4000? | 90 | 20(rated) | N/A | 100 |
| Tang Band 75-1558SH | 800 | 5000 | 90 | 25(rated) | 1.5 | 181 |
| Volt VM527 | 600 | 4000? | 90 | 75(AES) | 2 | 298 |
| Satori MD60N-6 | 700 | 4500 | 93 | 120?(rated) | 1 | 173 |
Please let me know what you think. Data of some drivers are sparse and maybe unreliable...
My apologiesHi macka,
Thank you for your comments and advices. I see many of your advices in line with my plan. I happened to use B2500.1 in my current system, and I prefer pulp cones for bass/midbass. For a higher WAF, I'd like to use 2 8" instead of single bigger one for the woofer section. If counting the SVS in, I am more like planning to end up with 5-way, but I am talking about only the part to plan and build in the future, so calling it 4-way.
There seems to be no Bliesma 2" dome, and you didn't mention Satori, so I take it that you don't recommend it.
There are other textile dome midhigh options you didn't mention, so I wonder what you think about HiVi and Tang Band 3" ones.
BTW, Is it JBL 4344? I heard it a few times in 2 places, and the last one sounded pretty charming and pleasing, though it wasn't exactly to my taste. Surely a masterpiece.
The the Bliesma is a 3 inch dome. But have a look at some of the online FR off axis tests. I will try and find the link.
The designer uses variable diaphragm thickness and geometry to improve the off axis response and they go up higher.
Your choice of dual 8 inch drivers has merit. If operating then up to the 800 hertz region you will need to account for baffle step. This is easily solved with EQ or in a passive network with two woofers.
You have lots of valuable input here.
Yes the Satori 2 inch dome does look good. The Visation fabric dome is also good.
My suggestion is to perhaps start with something like the Sartori dome mid and dome tweeter and get your system together structurally. If it has promise then opn
The wallet on higher performance drivers.
Yes the 4344. There are a number of modifications to improve the resolution of those systems. I use the 4345 with the 18” 2245H driver. The bass out of it is legendary.
I also would be remiss not to mention the original source and the room. Hearing a musician or singer live un amplified to quite a moment of truth. Let your ears be the judge on what is real, different or better.
The room’s impact cannot be ignored. It’s quite an unknown variable until you open up REW and look at the reverberation time and the water fall of the room.
Getting the absorption coefficient right at the listening position is more important than many people realise. This plays an
Important role in achieving the correct balance of direct and indirect sound while ensuring the resolution of the system is in fact translated to the listener.
Others you can find yourself the cat chasing its tail.
My own take on getting what you need out of a system is that it must translate as closely possible to the original recording.
This means minimal destructive errors (ref Earl Geddes) to what we decode as human.
Geddes in his presentations says the human ear is non Linear in several ways. Its non linear as most of us know in amplitude- loudness versus frequency.
But the ear is also non linear in detecting different distortion harmonics. Add to this the ear is more sensitive to distortion at low levels ( as l understand it ). High order harmonics of distortion also attract sensitivity.
There can be a tendency to confuse what highs are?
Above be 10,000 hertz or 3000-10000 hertz. It depends on what you think certain overtones actually are as a frequency. All musical instruments have overtones that often start with a fundamental in the lower midrange.
I think this is where coherence of a multi way system is impossible. Poor hand overs from one driver to the next are bad if you want those overtones to be coherent.
On that point a narrow face plate or no face plate tweeter right next to the dome mid is likely going to solve a lot of the practical versus performance criteria. It will act like a point source as far as coherence goes.
I used to have a system with that design and it was really insightful (Legend Acoustics Kantu 5) The mid was a 4 inch Aerogel cone driver. The dual woofers were 6.5 inch from Scan.
Looking the chart l personally find l am sensitive to the resolution or blurring over overtones above 8000 hertz. If the overtones are not crystal clear l can pick it out instantly and l am 64.
But recording engineers call this region “Air”.
I am just mentioning this but there is quite a lot in it.
Without air the music would be like a blanket over the loudspeaker.
This means minimal destructive errors (ref Earl Geddes) to what we decode as human.
Geddes in his presentations says the human ear is non Linear in several ways. Its non linear as most of us know in amplitude- loudness versus frequency.
But the ear is also non linear in detecting different distortion harmonics. Add to this the ear is more sensitive to distortion at low levels ( as l understand it ). High order harmonics of distortion also attract sensitivity.
There can be a tendency to confuse what highs are?
Above be 10,000 hertz or 3000-10000 hertz. It depends on what you think certain overtones actually are as a frequency. All musical instruments have overtones that often start with a fundamental in the lower midrange.
I think this is where coherence of a multi way system is impossible. Poor hand overs from one driver to the next are bad if you want those overtones to be coherent.
On that point a narrow face plate or no face plate tweeter right next to the dome mid is likely going to solve a lot of the practical versus performance criteria. It will act like a point source as far as coherence goes.
I used to have a system with that design and it was really insightful (Legend Acoustics Kantu 5) The mid was a 4 inch Aerogel cone driver. The dual woofers were 6.5 inch from Scan.
Looking the chart l personally find l am sensitive to the resolution or blurring over overtones above 8000 hertz. If the overtones are not crystal clear l can pick it out instantly and l am 64.
But recording engineers call this region “Air”.
I am just mentioning this but there is quite a lot in it.
Without air the music would be like a blanket over the loudspeaker.
Attachments
Last edited:
The above statements are quite misleading….and as a recording/mix engineer I cringe when people apply reference standard to recordings when no reference of destructive tones or forces exist…..none. There is no reference….listen to what sounds good…..create what sounds pleasing…..rinse….repeat.
I guess l went off topic. Anything to do with modern recordings is full of contradictions and controversy theses days.
Obviously if an artist decides to record a performance and artistically modify it with the engineer the only way to compare the translations is in the studio and the control room.
In a concert hall or a large studio at Abby Road studios a simple mic set up with minimal processing may be appropriate.
The tenant of what are the fundermentals of musical instruments and the range of overtones is relevant to associating frequency response with what is subjectively heard.
I do think Earl Geddes research is well founded on how specifically the human ear works.
In this presentation Geddes does allude to a discuss some myths and interesting unknowns about our hearing. I don’t have bookmarks on this presentation
Obviously if an artist decides to record a performance and artistically modify it with the engineer the only way to compare the translations is in the studio and the control room.
In a concert hall or a large studio at Abby Road studios a simple mic set up with minimal processing may be appropriate.
The tenant of what are the fundermentals of musical instruments and the range of overtones is relevant to associating frequency response with what is subjectively heard.
I do think Earl Geddes research is well founded on how specifically the human ear works.
In this presentation Geddes does allude to a discuss some myths and interesting unknowns about our hearing. I don’t have bookmarks on this presentation
Hi macka,
I was waiting to be able to quote your post, but that takes forever... so:
Based on some of the discussions this is my conceptual view of the proposed design.
There are a number of considerations not the least WAF.
What I want to do is a floorstander bass module and 3 cylindrical modules for midbass, midhigh and tweeter. I want to be able to swap a module(== driver(s) == a way). I might look into plastic pipes and/or 3-D printing options for those.
I was waiting to be able to quote your post, but that takes forever... so:
Based on some of the discussions this is my conceptual view of the proposed design.
There are a number of considerations not the least WAF.
Attachments
-
IMG_5050.jpeg
278.3 KB · Views: 13
What I want to do is a floorstander bass module and 3 cylindrical modules for midbass, midhigh and tweeter. I want to be able to swap a module(== driver(s) == a way). I might look into plastic pipes and/or 3-D printing options for those.
I am removing HiVi and Tang Band ones, as they look inferior to other options and/or the brand/presented data seem less reliable. I am adding Visation instead. I also found Beyma and some others used to have dome midranges. Scanspeak's cheaper one has a very peaky curve, so was excluded, too.
| Driver | Low Fc(Hz) | High Fc(Hz) | Sensitivity(dB/W/m) | Max Power(W) | Xmax(mm) | Price(USD) |
| ATC SCM75-150 | 300? | 2000? | 91? | 75 | 4 | 900? |
| Volt VM753 | 450 | 4000 | 92 | 100(AES) | 2 | 580 |
| Bliesma M74S-6 | 500 | 5000 | 95 | N/A?!?!?!? | 2.4 | 411 |
| Volt VM527 | 600 | 4000? | 90 | 75(AES) | 2 | 298 |
| Satori MD60N-6 | 700 | 4500 | 93 | 120?(rated) | 1 | 173 |
| Visaton G 50 FFL | 600 | 8000? | 89 | 120(nominal?) | ? | ??? |
Last edited:
I think the best approach is to first re appraise how your others drivers will work in with your proposed loudspeaker. Is it dsp or passive, what power amps are you planning.
The thing is it has work work on a functional level.
Do the low bass and the mid bass first.
Will the SVS sub work with your low woofers or mid bass woofers?
What is the operating range of your proposed woofers ? What is their efficiency or sensitivity?
Will the enclosure be sealed or bass reflex?
The dynamic characteristics of the SVS sub need to match your woofers.
Once you have what settled the choices of the mid dome are more defined
The thing is it has work work on a functional level.
Do the low bass and the mid bass first.
Will the SVS sub work with your low woofers or mid bass woofers?
What is the operating range of your proposed woofers ? What is their efficiency or sensitivity?
Will the enclosure be sealed or bass reflex?
The dynamic characteristics of the SVS sub need to match your woofers.
Once you have what settled the choices of the mid dome are more defined
Beyma MC115.
Dynaudio MD142. Older MD-76's.
Wharfedale Evo 4 domes can be bought as spares.
Dayton RS52 2".
Volt's 753, is also available in E version(8ohm), and the 752.
Scanspeak D8404, just hampered by the ridicilous price.
Legatia L3 (car audio) dome midrange, has a rated xmax of 6mm and 113hz fs.
Ciare HM 500 2".
Morel used to have the MDM-75.
Adam audio has the DCH 4" dome/cone hybrid, not sure about availability.
Etc.
JH> Yes they will be steep FIR filtering done in S/W on my M1 Mac mini. I currently have a Prima Luna EVO 300 integrated for mids, and Monolith 9-channel HT power amplifier used for woofers and tweeters. I also have a Job 225 which I plan to use for tweeters(used for another room system right now).
JH> Yes, I am planning to use my SVS below some point for all the channel in the system. It will be a 5.1-channel system after all.
JH> I haven't started thinking about it yet. Scanspeak and Volt are candidates, though it's wide open to others. Though I prefer pulp cones, I am curious about harder materials. I am planning a sealed one, as SVS will fill the lacking low bass and it is also a sealed box.
JH> Not sure what you mean exactly or how I can do that. We will have a lot of chat on this, too.
It's unfortunate that most of these are gone from the market. Dayton one looks surprisingly good on paper for its price. Actually, it sounds too good to be true at the price, to an audiophile spoiled by price tags of those 'audiophile' drivers.
Does anyone have measurements for the Wharfedale drivers? Legatia seems just as expensive as the Volt or ATC, surprised to see such price in car audio market(I know nothing about it, of course). I also excluded Ciare as its dome material is not textile. Maybe next time.
I listened to the 8404 in my DIY friend's new project, and it's very good, probably better than ATC, but waaaaayyyy too expensive. I will never afford such $$$$ drivers in my whole life. The 2 professional digital audio gears I want to buy for this project cost just a little more than 1 driver, lol.
Last edited:
It’s a shame some drivers are either NA or priced out of the market. I am hearing noises that Be might be replaced by Textreme once fabrication techniques are refined. Some compression driver manufacturers are testing diaphragm alternatives to BE. Eminence has a novel textreme diaphragm compression driver.