Ah, a caution!
Yes, I'd definitely agree with that, but frankly for a newbie I'd strongly caution against designing your own loudspeakers as a first attempt at all.
(..in other words I think the caution is moot for hahayan, plus he seems to have a more realistic expectations of development time and necessarily the amount of effort it will require. He's going to wind-up spending a LOT of time reading over the manuals to LEAP 5 .)The 15W500 has low mass vs. sd and high eff.. It also has a low energy storage and dissipation surround with good compliance at very low excursion potentials (once it's been "broken in"). (..closer to a paper surround in fact.) In conjunction with the recommended loading scheme (aperiodic large box) and T/S param's (i.e. relatively high Qts), it should provide very good depth. (..the same is true of the flat-damped surround of the PHL 10" mid.)
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In some form or another Akabak can, as can the BoxCad program with Soundeasy. The problem is accurately determining the amount (and "nature") of resistance the actual "vent" provides. Basically it's just a LOT easier to do this "empirically" (..build/test/build/test), and far more easy to go with a general rule and put up with net result.
Cardboard boxes and tape can make for nice prototyping with the empirical method. Beyma: TPL 150H
PHL Audio: 3040, with DDS Horn: DMB 10N Pro
18Sound 15W500, with DDS Horn: DVB 15N Pro
Large aperiodic enclosures for the mid and bass.
Subwoofer*s* based on Precision Devices: PD2150Great drivers, but I would use Beyma 21SW1600Nd in my subs, and think about Beyma 15P80Nd/Fe as my lowmid.
thx guys...
nothing prefect, i think i can get a good compression drivers with the E JMLC horn ,however know..in the near future..i will not have those skill to optimize he drivers with those horn, as it need a lot of measuring skill, redesign the phase plug.., tweak the compression..etc..it is beyond my imagination at this stage, but i can live with it...
for the bass section, i think i need to come up a flexible testing fixture, which allow me to quickly build and test..build n test..for the volume, amount of filling an vent length etc..something i can slide the rear panel for volume adjustment.
i am not that crazy for wanting to design my own horn, with OB bass..,
as i am building a speaker with 4 bass driver per side with individual cabinets
what may be the best approach to ensure good outcome.., ? build one of them ,based on some sort of assumption and get it right , then multiplier by 4..an then fine tune it...
or make 4 prototypes cabinets, and tuning all 4 of them at the sametime?
oh..i never think of using a sub beyond 18"..hahaha
nothing prefect, i think i can get a good compression drivers with the E JMLC horn ,however know..in the near future..i will not have those skill to optimize he drivers with those horn, as it need a lot of measuring skill, redesign the phase plug.., tweak the compression..etc..it is beyond my imagination at this stage, but i can live with it...
for the bass section, i think i need to come up a flexible testing fixture, which allow me to quickly build and test..build n test..for the volume, amount of filling an vent length etc..something i can slide the rear panel for volume adjustment.
i am not that crazy for wanting to design my own horn, with OB bass..,
as i am building a speaker with 4 bass driver per side with individual cabinets
what may be the best approach to ensure good outcome.., ? build one of them ,based on some sort of assumption and get it right , then multiplier by 4..an then fine tune it...
or make 4 prototypes cabinets, and tuning all 4 of them at the sametime?
oh..i never think of using a sub beyond 18"..hahaha
How did you figured that out, simply because of the construction of the surround or is it related to the value of the Qms?
In part it's the construction of the surround - there are more "pleats" and the material is "thinner". Then there is the upper end response that is less smooth - a classic sign of a surround providing less damping (..the PHL unit has this same behavior).
Qms relates almost solely to the effect of the spider, not the surround. The spider has little to do with the driver at very low excursion (beyond keeping the driver centered, blocking out-of-phase content from the rear, and damping the driver's diaphragm) . The loading of the driver itself (in box) is actually more relevant to the driver at very low excursion than the spider.
The fact that it is also a high Qms/Qts driver is a nice bonus with respect to its loading in-box.
Does this mean you are interested in Open Baffle bass?
IF it were me and I was forced to choose a mid-treble compression driver solution that has depth I'd do this:
1 Loudspeaker:
2 Bentwood Askew Horns 400hz Modified Iwata re-designed for 1.4" exit.
2 18 Sound ND 1480A drivers.
"Back-to-back operated out-of-phase" like a dipole.
correction: The spider has little to do with the driver at very low excursion. (..the surround is designed to keep the driver centered, blocking out-of-phase content from the rear, damping the driver's diaphragm, and has more to do with the driver at very low excursion increasing resistance and lowering eff.).
..must have been the holiday "spirits".
Yess, this is the kind of system that I would build over an unity. The HF section above, would go great with an array of 4*12" high duty LF drivers (or 15"). Why the array? It would further shape the directivity in the low region (along with the dipole behavior), making for a controlled transition from the CD horn to the low frequency module. This kind of system would have everything needed in a large room: huge spl, ambient reflections, etc. Build it for low diffraction and constant directivity and it would be a real winner.
Also, XT1464 - Constant Coverage HF Horn should do well, back to back, in this application.
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today..i play around those WIniso online and the Unibox for a 15N840 15" for ported
For WiniSD online - i get VB = 54.8L, FB = 48.19 hz
then i out those 2 data into Unibox: i get the following
Standard Design
Vb 64.1 L
Fb 45.91 hz
F3 51.08 -3db
Port min dia. ! 19.53 cm
Port length 10.20 cm
By VB..Fb ..
Physical Vb 54.8
Absorption, Qa 80 (USER input) (was at the spreadsheet already , a common data?)
Leakage, Ql 15 (on the sheet)
Port, Qp 80
Alpha, a 2.612
Vb 55.8
Fb 48.19
F3 36.98
Response peak 0.00
Peak at none
Port dia. not updated 9.65
Port length 10.96
Port 1. resonance 952
so how do i interpret first trial exercise?
let;s say i wanna cross with the horn at 700hz : the port resonance at 952 hz, so it is ok, port length and diameter seem reasonable to me
then i quickly notice..where and what i need to get further learning..
any quick advice for me? and the box size seem so small..
also from BMS, they recommend those
70L / 42 Hz, BRD = 180 mm / 476 mm long
85L / 35 Hz, BRD = 180 mm / 590 mm long
seem big different to above, and what is "BRD"
For WiniSD online - i get VB = 54.8L, FB = 48.19 hz
then i out those 2 data into Unibox: i get the following
Standard Design
Vb 64.1 L
Fb 45.91 hz
F3 51.08 -3db
Port min dia. ! 19.53 cm
Port length 10.20 cm
By VB..Fb ..
Physical Vb 54.8
Absorption, Qa 80 (USER input) (was at the spreadsheet already , a common data?)
Leakage, Ql 15 (on the sheet)
Port, Qp 80
Alpha, a 2.612
Vb 55.8
Fb 48.19
F3 36.98
Response peak 0.00
Peak at none
Port dia. not updated 9.65
Port length 10.96
Port 1. resonance 952
so how do i interpret first trial exercise?
let;s say i wanna cross with the horn at 700hz : the port resonance at 952 hz, so it is ok, port length and diameter seem reasonable to me
then i quickly notice..where and what i need to get further learning..
any quick advice for me? and the box size seem so small..
also from BMS, they recommend those
70L / 42 Hz, BRD = 180 mm / 476 mm long
85L / 35 Hz, BRD = 180 mm / 590 mm long
seem big different to above, and what is "BRD"
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