A more then great price if you chose the 18S
https://hoangbaokhoa.com/en/8nmb420-driver-8inch-neo-18sound-b47576.php
https://hoangbaokhoa.com/en/8nmb420-driver-8inch-neo-18sound-b47576.php
I know that - I'm not disagreeing on mathematical facts here. All I'm proposing is, that he measures both, since it is not really a true point source, and it is not really a true line array, and he still needs to get a good idea of his cross-over and dispersion of the given drivers in his given cabinet.
Further, we do not know the exact measurement of his room, listening distance, overall setup placement, absorption of the room at different frequencies... etc.
I'm only advocating to be curious and to try different approaches, since statistics often show, that we do not get it perfectly right the first time - especially when we get creative with our designs.
You have a good point about the multiple woofer approach, regarding the Eighteen sound driver. Except - I do not agree fully, that a lighter cone will be much better at pumping air - when used below 250Hz.
Just playing with an idea - I know it will not fit physically great in Theo's design though:
One of my friends have 2 of these in each speaker with an 8" coax, in his big living room, with 4 x 15" subwoofers:
https://sica.it/prodotto/10-sr-2-5-cp/
They play loud enough for even one of my horn-friends to be satisfied - and he likes it LOUD!
So as hifijim proposed on the first page of this thread - if you could ditch the idea of 2-3 x 8" woofers per section - and put one bigger driver instead - that would simplify things.
Running out of ideas for woofers.... but I look forward to seeing the further development
All good digitalthor and looking forward to watching how this excellent design develops.
I think TheoSweden's design is really interesting and will benefit from the line array / distributed bass which will reduce room interaction problems and mean much less DSP/Eq is required to fine tune the sound.
The mid and top is a high quality point source and with the excellent cabinet design/material and high performance DSP for crossovers should really showcase the drivers ability.
I agree that one big driver Vs lots of small drivers are both valid approaches and often aesthetics and room design dictate which path you go down.
TheoSweden's cabinets obviously are designed for multiple small bass drivers which are great all the way up to 300Hz, but just for interest, here is a Sim showing what a nice ELF design (designed to operate BELOW box resonance) 18 inch Pro driver can do in a small (70 liter) sealed box does below 70Hz... Major advantages are low cost / simple sealed box, reduced driver cost and simple installation/wiring/8 Ohm load. Eq to taste and room position and you have killer bass...
Using just 128 watts (less than 10% of the drivers AES continuous power handling 1,600 watts!!) and just 21% of the 13mm XMax (60mm travel before damage!) one sub holds the same 106dB at 40Hz with just 2.7mm cone travel. If you have a Kilo watt of Hypex type power available a pair (plus 3dB) in room corners (plus 6dB) can shake a 100 Kg sofa and the family sitting on it...!!
I think TheoSweden's design is really interesting and will benefit from the line array / distributed bass which will reduce room interaction problems and mean much less DSP/Eq is required to fine tune the sound.
The mid and top is a high quality point source and with the excellent cabinet design/material and high performance DSP for crossovers should really showcase the drivers ability.
I agree that one big driver Vs lots of small drivers are both valid approaches and often aesthetics and room design dictate which path you go down.
TheoSweden's cabinets obviously are designed for multiple small bass drivers which are great all the way up to 300Hz, but just for interest, here is a Sim showing what a nice ELF design (designed to operate BELOW box resonance) 18 inch Pro driver can do in a small (70 liter) sealed box does below 70Hz... Major advantages are low cost / simple sealed box, reduced driver cost and simple installation/wiring/8 Ohm load. Eq to taste and room position and you have killer bass...
Using just 128 watts (less than 10% of the drivers AES continuous power handling 1,600 watts!!) and just 21% of the 13mm XMax (60mm travel before damage!) one sub holds the same 106dB at 40Hz with just 2.7mm cone travel. If you have a Kilo watt of Hypex type power available a pair (plus 3dB) in room corners (plus 6dB) can shake a 100 Kg sofa and the family sitting on it...!!
Attachments
PS I am planning on building a pair of these sealed box ELF designs with a 300 watt into 8 Ohm power amp and DSP.
I have chosen a slightly higher Q to get the box resonance UP to 65Hz as I am crossing over at 65Hz... I lose a little bit of sensitivity but still only need 200 watts and 3.75mm cone travel to hit 104dB at 30Hz... A pair in the room corners.... OMG!
I have chosen a slightly higher Q to get the box resonance UP to 65Hz as I am crossing over at 65Hz... I lose a little bit of sensitivity but still only need 200 watts and 3.75mm cone travel to hit 104dB at 30Hz... A pair in the room corners.... OMG!
Agree
The problem is the size of the room, too small and not enough space behing and .front of the baffle to heard the bass. 50Hz is 6.8m wavelength.But why do you write this in this thread ? You are breaking dream of a lot of people here.
I think one of the reasons people don't immediately realize this is because the F3 is NOT the lower limit. With an F3 of 50hz you could likely have an F6 of 43hz and F10 of 38hz. (And probably higher output in an actual room, depending on the speaker placement.) Yes there is still plenty of musical content below 50hz, but it is not like the SPL drops to zero at 50hz.
Thor,I know that - I'm not disagreeing on mathematical facts here. All I'm proposing is, that he measures both, since it is not really a true point source, and it is not really a true line array, and he still needs to get a good idea of his cross-over and dispersion of the given drivers in his given cabinet.
Further, we do not know the exact measurement of his room, listening distance, overall setup placement, absorption of the room at different frequencies... etc.
I'm only advocating to be curious and to try different approaches, since statistics often show, that we do not get it perfectly right the first time - especially when we get creative with our designs.
You have a good point about the multiple woofer approach, regarding the Eighteen sound driver. Except - I do not agree fully, that a lighter cone will be much better at pumping air - when used below 250Hz.
Just playing with an idea - I know it will not fit physically great in Theo's design though:
One of my friends have 2 of these in each speaker with an 8" coax, in his big living room, with 4 x 15" subwoofers:
https://sica.it/prodotto/10-sr-2-5-cp/
They play loud enough for even one of my horn-friends to be satisfied - and he likes it LOUD!
So as hifijim proposed on the first page of this thread - if you could ditch the idea of 2-3 x 8" woofers per section - and put one bigger driver instead - that would simplify things.
Running out of ideas for woofers.... but I look forward to seeing the further development
I have build many loud playing systems, Troels The Loudspeaker 2/3 clone was one of them not so long time ago. But now I give this design a chance.. I think it can be good and look good. If the right drivers can be found
That brand was interesting, never heard about Sica before. How would a Sica 8S2,5CP https://sica.it/prodotto/8-s-2-5-cp/ perform in a sealed ~20litre box?
The price for them wasnt high, but do they perform?
Edit. Sorry, I forgot that you mentioned this driver earlier.
Last edited:
I really think this driver is great to listen to, I admit my knowledge ist as high as my building different-speakers-experience.
You have tried to convince me good but I must say I fear the high fs(maybe just preconception) and that I have to Eq much to be able get them to play deep.
I dont want my 18"s to play so high up in frequency..
Theo
Sica has nice drivers, their "studio" line, some coaxials and subwoofers which are very good usable for hifi speakers. Made in Italy.
I think that 8S2,5CP is a solid driver, but the parameter set seems to be made for ventend enclosure - from the TSPs I see no difference to other PA 8" drivers like a Faital 8RS350, the mentioned 18sound e.g...
Of course you can correct those with EQ, but would I take lower Fs / higher VAS drivers for CB, because in the enclosure the air suspension then dominates and linearizes Kms (which also can be assumed to be on the progressive side for the PA and PA based drivers...), and also I don't like too much boost to avoid power compression and thermal modulation effects. So for that use case I would prefer something like a 22W Discovery or Dayton RS225 in a comparable price range of the Sica.
However, for that limited bandwidth application, and with 4 drivers per speaker, just take a solidly made one without significant issues in the useable range, and go also a bit for nice looks and optics of the drivers!
I think that 8S2,5CP is a solid driver, but the parameter set seems to be made for ventend enclosure - from the TSPs I see no difference to other PA 8" drivers like a Faital 8RS350, the mentioned 18sound e.g...
Of course you can correct those with EQ, but would I take lower Fs / higher VAS drivers for CB, because in the enclosure the air suspension then dominates and linearizes Kms (which also can be assumed to be on the progressive side for the PA and PA based drivers...), and also I don't like too much boost to avoid power compression and thermal modulation effects. So for that use case I would prefer something like a 22W Discovery or Dayton RS225 in a comparable price range of the Sica.
However, for that limited bandwidth application, and with 4 drivers per speaker, just take a solidly made one without significant issues in the useable range, and go also a bit for nice looks and optics of the drivers!
I can't be certain. But if the Eighteen sound can do it - as a midrange driver - then this Sica should easily do it too.Thor,
I have build many loud playing systems, Troels The Loudspeaker 2/3 clone was one of them not so long time ago. But now I give this design a chance.. I think it can be good and look good. If the right drivers can be found
That brand was interesting, never heard about Sica before. How would a Sica 8S2,5CP https://sica.it/prodotto/8-s-2-5-cp/ perform in a sealed ~20litre box?
The price for them wasnt high, but do they perform?
Edit. Sorry, I forgot that you mentioned this driver earlier.
All I can say is - that its bigger brother works absolutely great in a small volume and sounds good - and can take a ton of beating 💪
But do some sims, all the data is there, and maybe you even need to buy one and test it out - before you buy 8
Again:
https://www.diyaudio.com/community/threads/8-woofers-40-250hz.409600/page-2#post-7613390
Note the T/S pic. in the negative review here:
https://www.parts-express.com/Dayton-Audio-PM220-8-8-Wideband-Midbass-Neo-Driver-295-345?quantity=1
https://www.diyaudio.com/community/threads/8-woofers-40-250hz.409600/page-2#post-7613390
Note the T/S pic. in the negative review here:
https://www.parts-express.com/Dayton-Audio-PM220-8-8-Wideband-Midbass-Neo-Driver-295-345?quantity=1
Last edited:
or 12I can't be certain. But if the Eighteen sound can do it - as a midrange driver - then this Sica should easily do it too.
All I can say is - that its bigger brother works absolutely great in a small volume and sounds good - and can take a ton of beating 💪
But do some sims, all the data is there, and maybe you even need to buy one and test it out - before you buy 8
It should have a better eq’ed result than most pure pro 8” drivers.
It’s lower Mms and lower Kms generally provide greater detail for a similar eff.. It’s also likely lower in odd-order harmonic’s with its more sophisticated motor and suspension design.
Cost is also comparable to 8” pro woofers.
Note that Vas is much lower than spec’ed, but Fs is also much higher: comparable to most 8” pro woofers.
Last edited:
Oh I’m just talking about linearizing the lower-end, that once done the overall result should be better.
Qtc (as a subjective result) is largely dependent on the driver-amp interaction with impedance. Consider making the cabinets aperiodic for the bass sections. I generally prefer something more critically damped: more resistance on the low-end.
http://www.teamaudionutz.com/tutorial/1/AP_Enclosures-The_Aperiodic_Cookbook
Qtc (as a subjective result) is largely dependent on the driver-amp interaction with impedance. Consider making the cabinets aperiodic for the bass sections. I generally prefer something more critically damped: more resistance on the low-end.
http://www.teamaudionutz.com/tutorial/1/AP_Enclosures-The_Aperiodic_Cookbook
The idea that line arrays drop only 3dB per doubling of distance is only valid in the near field, and is the result of level lost due to destructive interference. There is only loss of SPL in the near field compared to a point source.
The near field in a line array exists for any frequency and distance where moving farther away will result in more drivers summing coherently (close to “in phase”), instead of incoherently. Once all the drivers sum coherently, the far field is attained.
https://www.prosoundtraining.com/2010/03/17/line-array-limitations/
The near field distance can be defined by the following relationship:
D=1.57 L squared/λ
where
D is the distance to the far field transition
L is the physical length of the line source
λ = the wavelength of the frequency in question (all lengths in identical units).
Beyond this distance the listener is in the far field and there is 6 dB drop in level per doubling of distance.
The transition distance can be quite long at short wavelengths, that is, high frequencies, but it is shorter at low frequencies.
For each octave lower in frequency, the transition distance is cut in half.
At 250Hz the "line array" will be out of the near field cancellation region within a few meters and drop at 6dB per doubling of distance.
Of course, all this relates to a free field environment, indoors room modes and the Schroeder or "transition" frequency will dominate response.
And EQ Qtc to the shape you want