I remember sitting and manually grinding through all those calculations for the pure love of it. Still, getting my hands on some decent software was a revelation.
LinearTeam
This is a great start. The world is your oyster.
LinearTeam
This is a great start. The world is your oyster.
OK, guys, I surrender!!!!! If your modeling software is accurate; that tells me that the original OEM's published TSP's are not held to a nice, tidy tolerance of say +/- 5%. It tells me they are more like +/- 10, 20, 50 maybe even 100%!?? As some suppliers have told me, some brand names are very true to their specs. Other brands are known to be WAY off (I am avoiding those brands).
So, I would like to take a deep breath and move on here. Are there any other suggestions for a well designed, well built 8 inch we can all agree on? I am especially interested in your actual builds and the measured results in a real room listening environment. Thanks and regards!
So, I would like to take a deep breath and move on here. Are there any other suggestions for a well designed, well built 8 inch we can all agree on? I am especially interested in your actual builds and the measured results in a real room listening environment. Thanks and regards!
Actually, I did discover this WinISD 2 or 3 days ago and tried it. I'm still getting used to it. Guess what; I still got very similar results to my hand calculations even after entering a driver's entire TSP table. I am particularly interested in the Seas Prestige drivers because the box size calculates out to be quite small (that is what I'm looking for). BUT, they have also published FR's that are actual measured results using a 21L closed box corrected to 1 meter. Those Seas curves match almost exactly to my calculated results. (This tells me Seas data can be trusted!)
From my measurements (thousands) a really tight brand might be +/- 10%, +/-20% is more typical, and some samples have been huge.
dave
Was involved a RS225-8 build by xrk971 as far as i remeber our modeling was spot on to real world measurements using Dayton datasheet as data input, link to thread http://www.diyaudio.com/forums/full-range/273524-10f-8424-rs225-8-fast-ref-monitor.html#post4306110.
Active XO including Linkwitz transform filter:
Passive XO:
Expensive solution...Conventional designers will hate it!
Looking at the OP first post I have a left field, budget blowing option ...
See attached simulation.
Who says low Qts drivers dont work in small sealed boxes......Oh yea, all the guys who lived in the 19th century (before DSP and low cost high power amplification) and who wrote the text books that dominated the 20th century.....
Breaking news....This is the 21st century and low cost high quality DSP changes everything....Time to move on from the loudspeaker design cookbook and TS modeling based on frequency domain is king....
New game, new rules!
The last decade or so has seen huge advances in materials science, computer aided acoustic measurement and an understanding of human ear / brain function in the time domain that was simply unimaginable to the 19th & 20th century pioneers.
Where would modern medicine, physics, chemistry etc be if the best current products from those fields were dominated by the thinking and practitioners from the early 1900's....?
Anyway...Back to the driver!
Tiny Vb of 6.1 litres (total cabinet volume is 8.5 litres allowing for damping materials and volume occupied by driver)
Its easier (and cheaper) to make a small non resonant sealed enclosure rather than a big one.
Driver features linen surround and very high Mms to Bl ratio (15g Mms over 10 Bl = 1.5) and 0.707 sealed box Q....Very tight and fast bass with all the texture and detail that is only audible with time domain accurate loading....No TL / port delayed phase distortion here
Requires 280 watts max power and Eq.
Crossover at 200Hz to 400Hz to your wide band / full ranger is ideal.
The matching sub is flat to 20Hz in under 50 litres...
Down side ....£220 per driver plus shipping from UK. (Give it a few years it will be £100)
All the best
Derek.
Looking at the OP first post I have a left field, budget blowing option ...
See attached simulation.
Who says low Qts drivers dont work in small sealed boxes......Oh yea, all the guys who lived in the 19th century (before DSP and low cost high power amplification) and who wrote the text books that dominated the 20th century.....
Breaking news....This is the 21st century and low cost high quality DSP changes everything....Time to move on from the loudspeaker design cookbook and TS modeling based on frequency domain is king....
New game, new rules!
The last decade or so has seen huge advances in materials science, computer aided acoustic measurement and an understanding of human ear / brain function in the time domain that was simply unimaginable to the 19th & 20th century pioneers.
Where would modern medicine, physics, chemistry etc be if the best current products from those fields were dominated by the thinking and practitioners from the early 1900's....?
Anyway...Back to the driver!
Tiny Vb of 6.1 litres (total cabinet volume is 8.5 litres allowing for damping materials and volume occupied by driver)
Its easier (and cheaper) to make a small non resonant sealed enclosure rather than a big one.
Driver features linen surround and very high Mms to Bl ratio (15g Mms over 10 Bl = 1.5) and 0.707 sealed box Q....Very tight and fast bass with all the texture and detail that is only audible with time domain accurate loading....No TL / port delayed phase distortion here
Requires 280 watts max power and Eq.
Crossover at 200Hz to 400Hz to your wide band / full ranger is ideal.
The matching sub is flat to 20Hz in under 50 litres...
Down side ....£220 per driver plus shipping from UK. (Give it a few years it will be £100)
All the best
Derek.
Hi,
WinISD is very quick and dirty and basically gives you results
the same as hand calculations. It only needs Fs, Vas and Qts.
Putting in lots of detail is pointless, a lot is basically ignored.
WinISDpro is much better but is not guaranteed to be entirely
accurate. Still it lets you model a hell of a lot more.
Unibox is probably more entirely accurate. I've never used it.
The free version of Basta! is good for series capacitor loading.
rgds, sreten.
reduction in the speed of sound?
folks,
from wikipedia:
~"The effective volume increase can be as much as 40% and is due primarily to a reduction in the speed of sound, and not to the popular misconception of a change in operating conditions from adiabatic to isothermal."
may I suggest that the presence of a large amount of thin fibers in the stuffing force the sound waves to go not in a "direct, straith" ahead path, but in a very erratic and longer path, where the speed of the sound remains constant but the total distance percorred is bigger than without stuffing?
This could generate the same final result regarding speakers, but whitout changing the speed of the sound which seems not correct to me.
( english is not my native language, so I apologize for any "issues" with my text above)
Flavio
folks,
from wikipedia:
~"The effective volume increase can be as much as 40% and is due primarily to a reduction in the speed of sound, and not to the popular misconception of a change in operating conditions from adiabatic to isothermal."
may I suggest that the presence of a large amount of thin fibers in the stuffing force the sound waves to go not in a "direct, straith" ahead path, but in a very erratic and longer path, where the speed of the sound remains constant but the total distance percorred is bigger than without stuffing?
This could generate the same final result regarding speakers, but whitout changing the speed of the sound which seems not correct to me.
( english is not my native language, so I apologize for any "issues" with my text above
)Flavio
Stuffing does two separate things that influences the driver. Firstly, it adds thermal mass which changes how the air compresses to create sound (changes the spring constant of the trapped air) and secondly it provides a convoluted path through the fibres plus mass to pick up and shake which turns some of the kinetic energy of the air into heat (adds damping). Materials differ in how effective they are at introducing the two effects although this doesn't seem to get discussed much.
How does stuffing work....?
To be honest I am not sure exactly how different types and amounts / density of stuffing works in subs...I have read a lot of conflicting theories that sound plausible in their own right....
But one measurable effect is the change on the system Q ie low to medium density stuffing using Twaron ("Angel Hair") has the same effect as a 10% to 15% increase in box volume.
I have found this effect to be consistent and repeatable from small 8 inch drivers up to big 18 inch drivers.
One caveat is that I dont load my drivers with conventional TS / classic theory.
I use my version of Rod Elliot's ELF /Bag End theory, interesting read here :
Sub-Woofer Controller
All the best
Derek
To be honest I am not sure exactly how different types and amounts / density of stuffing works in subs...I have read a lot of conflicting theories that sound plausible in their own right....
But one measurable effect is the change on the system Q ie low to medium density stuffing using Twaron ("Angel Hair") has the same effect as a 10% to 15% increase in box volume.
I have found this effect to be consistent and repeatable from small 8 inch drivers up to big 18 inch drivers.
One caveat is that I dont load my drivers with conventional TS / classic theory.
I use my version of Rod Elliot's ELF /Bag End theory, interesting read here :
Sub-Woofer Controller
All the best
Derek
Well, thanks! I just might have had tons of plain, dumb, blind luck over the years. I always seem to choose very well behaved drivers that have repeatable and predictable results. So, this tells me that these drivers were manufactured to fairly high tolerances. I was totally serious about having many successful designs and builds (literally dozens). Based on your findings of +/- 10% being quite good and +/- 20% being more typical; I was most likely in the 10% (or better) realm. This DOES help explain things; the suppliers have been very helpful by suggesting brands that have accurate published specs. which is I why I have been avoiding other brands known to have very inaccurate specs. (possibly due to poor manufacturing processes!??).
Perhaps a higher variance?
And one has to remember that T/S are not scalars, they are curves. When a diyer measures and says his measures do not match the factory data it is more likely that he is capturing data from a different part of the curve. Getting a measure that comes close to replicating a factory set is likely more of an inication of how horizontal the curves are.
Also, 2 driver measures cannot be directly compared if not done in the same session (or in climate controlled space (temp, humidity, barometric pressure at a minimum))
dave
Looking at the OP first post I have a left field, budget blowing option ...
See attached simulation.
Who says low Qts drivers dont work in small sealed boxes......Oh yea, all the guys who lived in the 19th century (before DSP and low cost high power amplification) and who wrote the text books that dominated the 20th century.....
Breaking news....This is the 21st century and low cost high quality DSP changes everything....Time to move on from the loudspeaker design cookbook and TS modeling based on frequency domain is king....
New game, new rules!
The last decade or so has seen huge advances in materials science, computer aided acoustic measurement and an understanding of human ear / brain function in the time domain that was simply unimaginable to the 19th & 20th century pioneers.
Where would modern medicine, physics, chemistry etc be if the best current products from those fields were dominated by the thinking and practitioners from the early 1900's....?
Anyway...Back to the driver!
Tiny Vb of 6.1 litres (total cabinet volume is 8.5 litres allowing for damping materials and volume occupied by driver)
Its easier (and cheaper) to make a small non resonant sealed enclosure rather than a big one.
Driver features linen surround and very high Mms to Bl ratio (15g Mms over 10 Bl = 1.5) and 0.707 sealed box Q....Very tight and fast bass with all the texture and detail that is only audible with time domain accurate loading....No TL / port delayed phase distortion here
Requires 280 watts max power and Eq.
Crossover at 200Hz to 400Hz to your wide band / full ranger is ideal.
The matching sub is flat to 20Hz in under 50 litres...
Down side ....£220 per driver plus shipping from UK. (Give it a few years it will be £100)
All the best
Derek.
Thanks! Years and years ago, I traveled back and forth to Japan for more than 15 years as a part of my job. I got to see and hear many of their different products, some of which were never exported. Fostex and Coral (Copal sp?) had a very strong following for obvious reasons to the fullrange (FAST?) fans out there among you. Pioneer used to sell DIY drivers too. I tried a 4.5 inch driver of theirs in a closed box probably 4 liters max. This was both a woofer and wide band driver and they sounded great! I measured F3 at about 75Hz; they finally ran out of steam at 7KHz wherein I used a super tweeter. I don't remember any of the published specs. but everyone that heard these really liked them. And, they only cost about $35; today's US dollar maybe $85 to $100 each.
I forgot to mention this was a hybrid paper cone with a cloth (linen?) surround. This surround was coated in a rubbery feeling substance (probably silicon). [The above post reminded me of the linen].
I am considering https://www.madisoundspeakerstore.com/approx-8-woofers/audax-hm210c0-8-carbon-fiber-woofer/ and a Hivi RT2Pro.
This Audax seems as smooth as can be.
This Audax seems as smooth as can be.
In a 3-way the Prestige CD22RN4X in a closed box looks very good. Flat <450Hz and 20Hz FS
$125-$135
http://www.seas.no/images/stories/prestige/pdfdatasheet/h1192_cd22rn4x_datasheet.pdf
The L22RN4X/P is close but has an aluminum cone which is a no-no for some. Higher power handling than the CD22 and costs a little less. 21Hz FS.
$100-$110
http://www.seas.no/images/stories/prestige/pdfdatasheet/h1208_l22rn4x_p_datasheet.pdf
I have used both with great results, but I have not tried the L22 in a closed box. The CD22 however did very well. 4 of them in a 40L was a real surprise.
High quality 8" in closed box with Linkwitz Transform is nothing short of a revelation.
$125-$135
http://www.seas.no/images/stories/prestige/pdfdatasheet/h1192_cd22rn4x_datasheet.pdf
The L22RN4X/P is close but has an aluminum cone which is a no-no for some. Higher power handling than the CD22 and costs a little less. 21Hz FS.
$100-$110
http://www.seas.no/images/stories/prestige/pdfdatasheet/h1208_l22rn4x_p_datasheet.pdf
I have used both with great results, but I have not tried the L22 in a closed box. The CD22 however did very well. 4 of them in a 40L was a real surprise.
High quality 8" in closed box with Linkwitz Transform is nothing short of a revelation.
I got this old tread open again. Since I find a lot of information here, which I still find relevant. By doing so, I aim to see what modern solutions like multiple subwoofers and DSP has brought to the table.
Typically, I sense that most 8" drivers are chosen for either playing low, loud or fitting smaller cabinets. With tons of cheap power, DSP's and readably available simulation and measuring software, It now seems a bit outdated to purely focusing on a bump in the frequency response, when you actually just straighten it out afterward.
1. How much does the Q of 0,7 even matter anymore?
2. How much can we bend the rules?
3. When more people adapt to using subwoofers, how important is it to aim for deep extension with the mid-woofers, and what does it mean when choosing mid-woofers?
4. What really dictates sound quality from a typical 8" woofer, when all modern bells and whistles are used?
5. How much does cabinet volume dictate regarding sound quality? Does drivers with higher VAS have an easier time, if we just live with bigger cabinets?
6. How much do we tolerate when it comes to quality of a driver, when we go lower in frequency?
This is merely a brainstorm, to dig deeper into the perceptible level of sound quality, that we are able to sense - practically. In my "research", I bought an RS125 as midrange with my Seas DXT. When swapping to a SB MW13TX, I found it easier to listen to, and in general, voices were clearer and details in music were easier to detect - even when both constructions were measuring flat within +/-1dB.
This made me think, that maybe a Satori WO24 would be better than a RS225 as a woofer. But at the same time, I thought that maybe we can't hear the same level of detail in lower frequencies, with respect to our psychoacoustical hearing abilities.
Anyone who has an idea, or thought, regarding this?
Typically, I sense that most 8" drivers are chosen for either playing low, loud or fitting smaller cabinets. With tons of cheap power, DSP's and readably available simulation and measuring software, It now seems a bit outdated to purely focusing on a bump in the frequency response, when you actually just straighten it out afterward.
1. How much does the Q of 0,7 even matter anymore?
2. How much can we bend the rules?
3. When more people adapt to using subwoofers, how important is it to aim for deep extension with the mid-woofers, and what does it mean when choosing mid-woofers?
4. What really dictates sound quality from a typical 8" woofer, when all modern bells and whistles are used?
5. How much does cabinet volume dictate regarding sound quality? Does drivers with higher VAS have an easier time, if we just live with bigger cabinets?
6. How much do we tolerate when it comes to quality of a driver, when we go lower in frequency?
This is merely a brainstorm, to dig deeper into the perceptible level of sound quality, that we are able to sense - practically. In my "research", I bought an RS125 as midrange with my Seas DXT. When swapping to a SB MW13TX, I found it easier to listen to, and in general, voices were clearer and details in music were easier to detect - even when both constructions were measuring flat within +/-1dB.
This made me think, that maybe a Satori WO24 would be better than a RS225 as a woofer. But at the same time, I thought that maybe we can't hear the same level of detail in lower frequencies, with respect to our psychoacoustical hearing abilities.
Anyone who has an idea, or thought, regarding this?
In general, you either have good deep bass properties with disadvantages in terms of precision and tightness in the upper bass area and the mids, or it's the other way around: Clear and tight bass with very high resolution in the upper bass area and midrange, but without the blackness in the sound, i.e. without really good properties in the area of ultra low frequencies between 20 and 50 Hz.
Either this driver under
https://www.diyaudio.com/community/threads/obscure-peerless-xls-style-8-sub-woofer.398960/
or this examples under
https://www.fane-international.com/downloads/FANE-SOVEREIGN-PRO-8225-DS141117.pdf
https://www.eighteensound.it/en/products/lf-driver/8-0/8/8NMB420
https://www.eighteensound.it/en/products/lf-driver/8-0/8/8MB400
Both advantages without the disadvantages of both at the same time isn't possible - so I think.
Drivers who combine both advantages to a certain extent are these models:
https://voltloudspeakers.co.uk/speaker/bm228-8-8inch/
https://voltloudspeakers.co.uk/speaker/b220-2-8inch/
https://www.costruireaudio.com/en-gb/volt-b220-2-woofer-8-20-cm.html
Either this driver under
https://www.diyaudio.com/community/threads/obscure-peerless-xls-style-8-sub-woofer.398960/
or this examples under
https://www.fane-international.com/downloads/FANE-SOVEREIGN-PRO-8225-DS141117.pdf
https://www.eighteensound.it/en/products/lf-driver/8-0/8/8NMB420
https://www.eighteensound.it/en/products/lf-driver/8-0/8/8MB400
Both advantages without the disadvantages of both at the same time isn't possible - so I think.
Drivers who combine both advantages to a certain extent are these models:
https://voltloudspeakers.co.uk/speaker/bm228-8-8inch/
https://voltloudspeakers.co.uk/speaker/b220-2-8inch/
https://www.costruireaudio.com/en-gb/volt-b220-2-woofer-8-20-cm.html
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@digitalthor Sure a wo24p is a killer ! You won't regret to use it !
For me bass reproduction is the harder part in a speaker. As explained above you have masking effects. A good motor can minimise these effects. Don't try to go too low in frequency.
Purifi builds drivers with low imd, they have a test with two tones 30Hz and 255Hz.
For me bass reproduction is the harder part in a speaker. As explained above you have masking effects. A good motor can minimise these effects. Don't try to go too low in frequency.
Purifi builds drivers with low imd, they have a test with two tones 30Hz and 255Hz.
Long response to all these questions of what I observe, my first response was story short.
1. It is question of response extension and phase behavior in closed box. Depends on the driver and the design, some drivers can work well with Q=0.7 and some Q=0.8.
2. For me it is guidelines, no rules to bend. The designer makes his choices. Bass extension depends on a lot of parameters like the amplifier, the room etc.
3. It is a smart solution to use dedicated subwoofers, cut above 150Hz the satellite that things can be great in the midrange-treble.
4. Depends on your specifications and how do you use the driver and the limits you choose. If you use a 8" in the range 30-2kHz, you cannot have big bass and a clear midrange than if you use it in the range 50Hz-2kHz. I own several 8" and they are all good when correctly used, some gives best defintion than other because they have more advanced motor or more rigid cone etc. You can have good compromise depend on sensitivity-bass extension-treble extension.
5. I didn't notice relation with sound quality and correct volume used. The problem is bass extension and sensitivity. My SICA 8H2CP in only 28L@34Hz bass reflex (F3=40Hz) gives enough bass and a very good midrange, with the 22W8534, higher Vas in the same volume, closed box, F3=60Hz but 2dB more senitivity. The SICA have a better midrange because its motor is better than the 22W8534 motor and I cut lower the SICA 1800Hz vs 2500Hz.
6. Go lower in frequency with a big driver, you need quality when you go low in frequency, a well ventilated frame, and a good motor to handle large linear displacement.
No typical answers, depends on a lot of parameters.
Yes you can hear very different level of details in bass. Some drivers can do miracle in this area. There are notes in Bass and not all drivers could clear detached these notes. Bass in not boom-boom or dong-dong ...