- Looking around for an 18" woofer for my next speakers (to about 500 Hz). Is there a reason why not to choose one from the SB Audience line of subwoofers - https://www.sbaudience.com/index.php/products/subwoofers/ ?
(I have just realized that a 21" would still fit...)
(I have just realized that a 21" would still fit...)
really think 500 hz is too much for a 18"... you risk the too thick human voice, imho ! I would give up at 200/250 hz...
Nothing should stop you to use a 12" or a 15" for that 500 hz cut-off and if you wish, whatever the reason use the 18" or 21" below 50 hz for instance if using the 12" or the 15" in between. I am not sure a 21" has any interrest... push-pull or push-push of 18", why not however !
just my 2 cents, I am sure some may think different . I have the feeling we should think the low bass in focusing on the load and room instead of the cone surface of a standalone driver. We turn inn circle tempting the perfect two ways because of the filters limitations, imho ! Just a feeling, dunno if technically accurate but I put he idea on the table !
Nothing should stop you to use a 12" or a 15" for that 500 hz cut-off and if you wish, whatever the reason use the 18" or 21" below 50 hz for instance if using the 12" or the 15" in between. I am not sure a 21" has any interrest... push-pull or push-push of 18", why not however !
just my 2 cents, I am sure some may think different . I have the feeling we should think the low bass in focusing on the load and room instead of the cone surface of a standalone driver. We turn inn circle tempting the perfect two ways because of the filters limitations, imho ! Just a feeling, dunno if technically accurate but I put he idea on the table !
Well, some guys as Hiraga think 18" are too big for human voices (understand do not use it (the 18") above 100 hz, limit 200 hz at your risk) . I tend to agree with guys having heard tons of loudspeakers ! But yes, not writed in the marble, audition is complex ! I belieeve he talked not only about the patern but what is a 18" and more cone is for that frequency task, at least I guess !
If one 18inch is not enough, here is some information that Kimmosto recently shared about his dual 18inch cardioid design..
Post in thread 'End Game DIY Loudspeakers' https://audiosciencereview.com/forum/index.php?threads/end-game-diy-loudspeakers.40519/post-1434865
Here is some details about its technical performance
Post in thread 'End Game DIY Loudspeakers' https://audiosciencereview.com/forum/index.php?threads/end-game-diy-loudspeakers.40519/post-1434983
Kimmosto says this speaker sounds fine in room sizes from 6m squared to 40m squared sizes..
Have you considered the JBL Dual Differential voice coil units?
The DD drive should completely cancel any 2nd harmonic distortion from flux modulation.
Only the top of the SB line seem to have conductive structure to reduce flux modulation, and it's only reduction, not cancellation.
Your horn looks very much the size and proportions that I want, I look forward to see how it turns out.
Best wishes
David
How about that:
Code:
R-OSSE = {
R = 108.41 ; [mm]
a = 50.618 ; [deg]
r0 = 12.7 ; [mm]
a0 = 8 ; [deg]
k = 2.0601 ; []
r = 0.26841 ; []
m = 0.75543 ; []
b = 0.48209 ; []
q = 3.7893 ; []
tmax = 1.0691 ; []
}
Rot = 2.8192 ; [deg]ST26Wr3 full report, forgot it yesterday:
Optimized small (I did not specifically design it small just free the parameter for the optimization) full report:
Comparison Normalized at 00deg
Comparison Normalized at 10deg
Do you see this design as an improvement over the ST260Wr3 based on whatever target you had in mind?
The bonus is a smaller size which should not impact the XO point if >1000Hz.
BTW, when one uses the 10Deg for normalization, for an axisymmetric device, one sort of use the LW for normalization (10deg weight is about 45% in the LW).
The CEA2034 shows the DI calculated with the LW (SPDI). The ON axis only accounts for 11%, (20deg and 30deg weights are 22% each) but is "probably" the axis on which a lot of artefacts (diffraction and others) are present.
Therefore, I do think one has to make the ON as smooth as possible and not just ignore it (I am not saying this is what you are doing) so the artefacts are also minimized.
With an optimizer (or without), there is no reason NOT to try to get both the LW (or 10deg) AND the ON as smooth as possible, I suspect that Tom is doing that.
However, I have seen some of the designs you presented exhibiting some artefacts ON. Example:
https://www.diyaudio.com/community/...he-easy-way-ath4.338806/page-489#post-6991655
In addition, it does not make sense to normalize to anything but 00deg for general devices (not axisymmetric) unless the design is specifically aimed at a different listening axis.
Those are really interesting. Nice non-resonant impedance curve above fs and very low inductance.
Difficult to find any reviews. One here have made OB thought.
https://www.diyaudio.com/community/...18sw450-first-impressions-open-baffle.366042/
You mean the 18" (or 21") needs off-axis dispersion there to meet the horn's one for constant directivity around 500 hz?
No way to cut off below the Schroeder frequency of most of the rooms (150/250 hz ?) where they dominate and use the horn from there with a tri or bi-axial (BMS) or the Axi from Emminence for instance ... well, ok, bigger throat size...dead end if I understood ! Ther are few designs with big horns around 300 hz... I do not remember the one of an australian small hifi business based on JMLH expansion ?!
Did you plan to use a 1" CD exit ? which compression copes with 500 hz (B&C DE550) without too much stress ?
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No, the idea behind the ring insert is to use a waveguide that starts as deep into the driver as possible and continues without any extensions, i.e. the ring part is actually a part of this waveguide.
See this Desmos graph - https://www.desmos.com/calculator/xokkqpqu9h
Set r_D0, r_D1, l_D (all the way down in the list) for a specific driver and then simply draw a waveguide that fits into the duct.
(Note that you can also set a0 < 0.)
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https://data-bass.com/#/drivers/5b5f77b99e7e420004dab2f8?_k=kjs579
Are you going with an open baffle?
If you should choose a sealed or resistance cab the old trusted BMS 18N862 is hard to beat. It’s fairly light moving mass (260g) and low Fs (25Hz) but not the cheapest on the market.
Just my subjective comment, the measurements are long gone. Using the JBL 2245 18" under a JBL 2360 horn with BMS 4590 crossed at 550-600Hz worked really well. Using Audiolense after my best try of linearizing the system with EQ first, the system left me with little urge to improve anything. Music first!