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Multi-Way Conventional loudspeakers with crossovers

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Old 16th April 2019, 03:33 PM   #11
mbrennwa is offline mbrennwa  Switzerland
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Quote:
Originally Posted by Windforce85 View Post
Budget is too low.
No. The budget goal is what it is. Having clear design goals is useful to make the right decisions when designing the speaker.
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Old 18th April 2019, 07:20 PM   #12
Arnandsway is offline Arnandsway  Netherlands
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Quote:
Originally Posted by Windforce85 View Post
You meant controlled directivity, not constant. If constant, specify value and frequency range.
No. 16 mm with dense reinforcements is better from gross volume and weight consideration. You want the thing to be compact. Thinner MDF tends to be stronger per slice area as well.
Budget is too low.
Woofer's choice is wrong from low bass efficiency in small enclosure. After LT linearization to required extension it will run ot of rated power or driving voltage range. Search for woofers with decent power rating and with Bl^2/Re value higher than 12, don't affraid elevated Mms.
Better use VituixCAD 2, it is a real design-devil for free.
Thanks for the feedback.

What are the specific specifications I should prioritse?
I know EBP should be favorable <80, VAS and FS should be relatively low (<25L and <40hz)
But where do I go from there?

I (think) I'd rather have a aluminium woofer because of the CSD is better than most paper woofers and helps against the back wave, and also because I want to use an aluminium tweeter.
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Old 18th April 2019, 07:43 PM   #13
Windforce85 is offline Windforce85  Poland
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Becouse of using DSP your powers unleashed. You don't need to stick to '70s T-S theory anymore. Your main points of consideration are:


- large Bl^2/Re
- large Sd * Xmas
- not too low Mms
- high long-term power rating
- stiff diaphragm material

- clever DSP work
- low and linear Le*

First parameter defines ability of the woofer to work efficiently in small (relative to Sd * Xmax) enclosure, second gives you objective information about bass capability of the woofer, third is necessary for bass efficiency maximization of combined enclosure-woofer-amplifier-DSP electromechanical system, fourth is necessary for low thermal compression and reliable operation in small enclosure after bass equalization, fifth is for durability and pistonic motion in as broad frequency range as possible, the last is a necessary binding factor for all the above aspects. The most important is Linkwitz-transformation a-ka bass equalization.

Your target of using metal drivers is right, sound of modern transducers under DSP equalization is counterintuitive to material's physical properties and other beliefs. You can focus on aesthetic and functional sides of the project and choose cabinet volume in a broad range of available alignments without much bothering (in acceptable range of woofer rated power and amplifier driving voltage).

*for midrange clarity.
In a last word - bass qualities from DSP sealed boxes (that's why I started from this) combined with midrange qualities (diaphragm, Le properities) leads to unusually low IMD content in the acoustic signal and to great quality of sound reproduction.

Last edited by Windforce85; 18th April 2019 at 07:52 PM.
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Old 18th April 2019, 09:33 PM   #14
5th element is offline 5th element  United Kingdom
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Originally Posted by LineSource View Post
The SB17NBAC-4 does not start beaming from the 180-degree baffle-controlled polar directivity until above your 1.5kHz crossover, so a tweeter waveguide would create an abrupt change in polar directivity around the crossover.
With a 5" waveguide though it shouldn't really be affecting directivity down at 1.5kHz and have similarly wide dispersion to the sb17.

The nice thing about the sb17 is that although it breaks up like a classic metal cone it doesn't have any of the usually associated distortion products. A 2.5khz cover to a 5" waveguide would work fine. As should an xover at 1.5kHz.
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Old 18th April 2019, 11:10 PM   #15
Soldermizer is offline Soldermizer  United States
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Default Consider a coaxial driver?

If you will be using subs and/or you don't need much below 100 Hz or so, why not consider a smaller (5") coax driver? These can be of high quality (and price!) like BMS, or ....? You get slightly better alignment (2 dimensions) instead of just one dimension (height) with a "normal" baffle. Time alignment should be easier with a coax. The downside (there always are trade-offs) is .... ?
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Old 21st April 2019, 08:13 PM   #16
Arnandsway is offline Arnandsway  Netherlands
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Aha, that's very helpfull.
I see to recquire a BL^2/Re of 12 I'd need a 8 inch woofer, from a quick look around.
I wonder though, because I want to cross them over to subs at 80-90hz, if a 6-7" would be sufficient anyways.
I worry about driver to driver distance and also the size of the speaker would be getting pretty wide. I acknowledge that maybe I'm asking too much from a small speaker, but wonder where the practical minimal requirements are for a f3 of 70 Hz from a relatively small sealed speaker.

Otherwise I might have to think about dropping the idea of a "full-size" WG and go for the Seas DXT tweeter to maintain the smallest driver to driver distance.
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Old 21st April 2019, 08:18 PM   #17
Arnandsway is offline Arnandsway  Netherlands
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Quote:
Originally Posted by Soldermizer View Post
If you will be using subs and/or you don't need much below 100 Hz or so, why not consider a smaller (5") coax driver? These can be of high quality (and price!) like BMS, or ....? You get slightly better alignment (2 dimensions) instead of just one dimension (height) with a "normal" baffle. Time alignment should be easier with a coax. The downside (there always are trade-offs) is .... ?
Ah just read your reply after posting my reply above.
As I said, f3 of 70 Hz to cross to subs at 80-90 hz is my plan.

A coax would be a nice idea too, especially for near-field. But I'm even less knowledgeable about good coax drivers. I know Seas has a great one, but is too expensive for me. Thought about using a fullranger as well, but worry about high frequency response.
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Old 21st April 2019, 08:23 PM   #18
Arnandsway is offline Arnandsway  Netherlands
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Quote:
Originally Posted by 5th element View Post
With a 5" waveguide though it shouldn't really be affecting directivity down at 1.5kHz and have similarly wide dispersion to the sb17.

The nice thing about the sb17 is that although it breaks up like a classic metal cone it doesn't have any of the usually associated distortion products. A 2.5khz cover to a 5" waveguide would work fine. As should an xover at 1.5kHz.
The SB driver looks great to me because of the low distortion yes.
How to match directivity correctly, still is confusing to me. Could you maybe respons to my reply at Linesource on page 1?
I thought on average a 6,5" driver would start beaming at around 1,5 khz, making a crossover at this frequency preferable.
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