Open Source "Tower XL"

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Important note Nov. 2018:
This free open source project is for DIYers only. DIYers may build and enjoy and maybe adapt this project for their own personal use, This project made possible by a lot of members donating their time, experience and money. Please do not use the information developed in this open source project in ANY commercial use or product.



Following "Open source speaker project?" and "Open source speaker project - Part II" this thread will be design thread for "Tower XL".

Tower XL Goals : amp friendly (high efficiency) and flattish impedance curve of 8 ohms, low bass extension of 35-40Hz within -3db and cabinet volume will be up to 150 liter. Drivers costs will be maximum of 1000$ for the pair ( excluding crossover parts and cabinet).

Drivers will be chosen to meet the task's goals (no size criteria at this point). Stated goals are not fixed and may change (not drastically) as design team needed.

and of course everyone is welcome to help and participate :)

Update (10-22-18):

It will two versions of Tower XL, Acoustic Elegance and Faital Pro Versions.

After a lot discussions, research and simulation Acoustic Elegance TD15X has been chosen as the woofer for this project, but due to limited worldwide availability and high shipping costs and manufacturer lead time, we decided to go with two versions and Faital Pro 15H520 as the woofer of choice for alternative version with trying to keep same form factor in mind, front baffle will be the same dimension for both versions but due to higher VAS of AE driver the AE tower need will be deeper.

Midrange: AE TD8M will be used for AE version and for Faital Pro version current candidate is Faital Pro 8PR200.
Tweeter: Faital HF107 + STH100 is the driver of choice for AE version.

More details about cabinets:

Tower XL AE
- Cabinet W x H x D = 47 x 112 x 62 cm
- Woofer AE TD 15X, Midrange AE TD 8M, Tweeter tbd
- 247 L bruto and 217 L netto for the woofer; 20 L bruto for the midrange, 5 L for the woofer and 5 L for the bracing subtracted
- Internal cabinet netto volume for midrange is 15 L
- Port length long: FB = 20 Hz, F3 = 35 Hz, F6 = 24 Hz, F10 = 19 Hz
- Port length short: FB = 28 Hz, F3 = 28 Hz, F6 = 25 Hz, F10 = 22 Hz
- Data for BR simulation: netto volume = 43.2 cm x 57.1 cm x 88 cm or 217 L; port long = 57.9 cm; port short = 24.0 cm; port area = 236 cm2

Tower XL Faital
- Cabinet W x H x D = 47 x 112 x 50 cm
- Woofer Faital 15FH520, Midrange 8 inch tbd, Tweeter tbd
- 195 L bruto and 165 L netto for the woofer; 20 L bruto for the midrange, 5 L for the woofer and 5 L for the bracing subtracted
- Internal cabinet netto volume for midrange is 15 L
- Port length long: FB = 25 Hz, F3 = 53 Hz, F6 = 34 Hz, F10 = 22 Hz
- Port length medium: FB = 36 Hz, F3 = 35 Hz, F6 = 31 Hz, F10 = 28 Hz
- Port length short: FB = 39 Hz, F3 = 36 Hz, F6 = 33 Hz, F10 = 30 Hz
- Data for BR simulation: netto volume = 43.2 cm x 45.1 cm x 84.7 cm or 165 L; port long = 57.9 cm; port medium = 24 cm; port short = 13 cm; port area = 236 cm2

more info can be found here.
 
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Assuming this is a tower speaker? A 15" driver will not fit on the front because it is too wide. If it is put on the side it will have to be crossed low like a subwoofer forcing the midrange to become a large midwoofer and compromising upper midrange/tweeter response. This could be handled with a large waveguide on the tweeter but, again, will it fit on a narrow baffle?

So is this a tower speaker or not? If it is not then it might be wise to make that clear so people can make sensible contributions.

What is the width of the baffle? Large, small or no waveguide? What size is the midrange or midwoofer? How many woofers: 4, 2, 1? How many midrange/midwoofers? How are the drivers arranged? What is the minimum sensitivity of the complete speaker and why? Is 40 Hz low frequency extension acceptable for a massive home speaker? Ported, sealed or something else? Open baffle was talked about at one point? Etc, etc...

If the basic configuration hasn't been sorted how can we determine if a suggested driver is or is not suitable?
 
Assuming this is a tower speaker? A 15" driver will not fit on the front because it is too wide. If it is put on the side it will have to be crossed low like a subwoofer forcing the midrange to become a large midwoofer and compromising upper midrange/tweeter response. This could be handled with a large waveguide on the tweeter but, again, will it fit on a narrow baffle?

So is this a tower speaker or not? If it is not then it might be wise to make that clear so people can make sensible contributions.

What is the width of the baffle? Large, small or no waveguide? What size is the midrange or midwoofer? How many woofers: 4, 2, 1? How many midrange/midwoofers? How are the drivers arranged? What is the minimum sensitivity of the complete speaker and why? Is 40 Hz low frequency extension acceptable for a massive home speaker? Ported, sealed or something else? Open baffle was talked about at one point? Etc, etc...

If the basic configuration hasn't been sorted how can we determine if a suggested driver is or is not suitable?

yes your assumption is right it is a tower and yes 15" is too large for a front tower style IMO but it is still possible to stay in a tower style foot print, but this is not a fixed set spec, any suggestion how to achieve mentioned "goal" of going low (maximum f3 of 35-40Hz, but the lower the better) and still keep the high sensitivity is absolutely welcome, either using one woofer or 4 as long as it keeps the price and specs as mentioned in first post. width of the baffle, number of woofers/ mid ranges and sizes... is all depends on how to reach the goal and stay within the limits (mostly budget). it would make it easier after we figure out LF part, so it is flexible! I do not know how but if you can get to 35-40Hz with sealed box of mentioned size I do not think anybody would mind but let's say ported to get things simple. no open baffle ( as you see no OB option was in the poll). goal is to keep this as simple as it can be, this will encourage less experienced users. I mean to avoid complicated CNC machined baffles, and also not requiring a carpentry degree ! hope this answer all you questions. almost all this info is available through previous poll and discussions.
 
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Aatto,

The sims, all B4 alignments.

BMS 15N630
Cabinet = 125 L and tuned at 39 Hz, F3 = 40 Hz and sensitivity = 96 dB half space

Faital Pro 15FH520
Cabinet = 130 L and tuned at 39 Hz, F3 = 39 Hz and sensitivity = 96.5 dB half space

Eminence Kappa 15FLA
Cabinet = 145 L and tuned at 39 Hz, F3 = 40 Hz and sensitivity = 97.4 dB half space

The Eminence Kappa needs more volume, because of lower Qts and higher Vas. Highest sensitivity, 91.4 dB full space ... almost the 92dB full space.

The Faital has a high Qms = 10.25, interesting...
 
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Achieving a high efficiency 8 ohm speaker with low extension is the main factor here and all falls under woofer's territory, so I suggest to start with possible woofer candidates.

I would suggest a poll is in order to see how many users will accept a 15" woofer > especially when a pair of 12" woofs would also ( more than ) deliver the SPL & extension requirements.

A pair of 12" woofers can offer more design flexibility ( ie; TMWW, > even a 3.5 arrangement ) and give a nicer looking tower ( IMHO )

:)
 
totally agree about the looks and the fact that if we can achieve that with smaller woofer there's no need for a huge 15 incher, but finding a woofer even within 15 inch range to meet needed specs is not easy, 16 ohm woofer for a TMWW also not easy to come by, so what do you suggest ?
 
I would suggest a poll is in order to see how many users will accept a 15" woofer > especially when a pair of 12" woofs would also ( more than ) deliver the SPL & extension requirements.

A pair of 12" woofers can offer more design flexibility ( ie; TMWW, > even a 3.5 arrangement ) and give a nicer looking tower ( IMHO )

We've had that discussion before. I fully agree with your, except that using two woofers means you'll have to find suitable 16 Ohm drivers. The choice is rather limited compared to the 8 Ohm world.
 
Aatto, mbrennwa,

Right, I forgot you're currently set on a minimum 8 ohm impedance.

For my own purposes, I always allow 4 ohms as the minimum impedance.

You may find that others may accept that lower impedance choice ( POLL ? ), once they understand the trade-off realities ( when pursuing sensitivity ).

:)
 
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Really?

I guess I missed some implied meanings that were baked into that poll (since there's no specific mention about impedance limits in any of the polling questions that I can see).

I now wonder how many others may be in the same boat (regarding confusion over "what's an allowable impedance curve").

:)
 
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