3-way floor standing speakers build thread

[stonemarten]

Dear experts,

thanks to the great help found here, I would like to share what I'm building:

The orange are mids, yellow tweeter and blue the woofer.

Here the wood for one speaker (I'll do the second later )

This is glulam Japanese Cedar, 18mm thick. Every outside panel is 2 pieces glued. I used wood pin for better alignment

As "wood press", I used more than 150kg of water boxes for every panel.

First wrong assumption: the panels are not really flat... this is the result

I'm trying now to fix the issue: will post the result in a couple of days

cheers

 

[TLS Guy]

Dear experts,

thanks to the great help found here, I would like to share what I'm building:

View attachment 14621
The orange are mids, yellow tweeter and blue the woofer.

Here the wood for one speaker (I'll do the second later )

View attachment 14622

This is glulam Japanese Cedar, 18mm thick. Every outside panel is 2 pieces glued. I used wood pin for better alignment

View attachment 14623 View attachment 14624

As "wood press", I used more than 150kg of water boxes for every panel.

First wrong assumption: the panels are not really flat... this is the result

View attachment 14625

That looks all very nice, but what is the design? A fancy box and a dumb design is a fancy box and that's all. If you are posting here, I assume you want peer review of the design, drivers, box alignment and crossovers.

The Net is replete with fancy speaker boxes, that are useless.

You really have to have a good design nailed down before you order any wood and certainly before making the first cut.

I'm trying now to fix the issue: will post the result in a couple of days

cheers

 

[stonemarten]

TLS Guy,

here the response modeler sheets that I used for the calculation

The drivers are:

- SB Acoustic SB26ADC-C000-4
- TB W4-1337sd
- RCF L8S800
all in a single enclosure

That will be driven by a couple of Crown XLS1000. The crossover part will be hybrid, with the MiniDSP 2x8 for the first split and then a passive for the mid-high split.
I have a Dayton DTS for the drivers measurements and the MiniDSP UMIK-1 for the speaker measurement.

cheers

 

[ARES24]

Please tell me this isn't your first DIY project....

Don't get me wrong I love enthusiasm but this seems like a project attempted for someone who has built 5+ pre-designed speakers. You have the 'measurements' but tactile experience is important.

 

[TLS Guy]

Let me be brutally honest.

That project is a waste of effort.

The woofer has an Fs of 60 Hz, which sets the lower response limit. From your impedance curves your enclosure is sealed. This agrees with your model with and F3 north of 100 Hz. That woofer has no reserve for Eq.

The mid range is reasonable up to 7 KHz, but those units are low powered. So you have max power of 50 watts in the mid range. There are huge power demands in the mid range.

You have selected an aluminum diaphragm tweeter with a break up mode well in the audible range. This is a common fault of this class.

The bottom line is that I could design a two way bookshelf that would outperform that design by leaps and bounds.

Sorry, but if you are going to put that much effort into a box, then you need a much better and more robust design.

 

[stonemarten]

Experts,

thanks for the feedback, appreciated.

This is not my first project, but yes, it's the first where I pick the drivers one by one and build the crossover. All the others were a 3-way kits, with drivers and crossover, I did only the cabinet.

Since I have already all the components, I will finish one speaker and test it and post the result.

I will use it for learn.

cheers

 

[TLS Guy]

Experts,

thanks for the feedback, appreciated.

This is not my first project, but yes, it's the first where I pick the drivers one by one and build the crossover. All the others were a 3-way kits, with drivers and crossover, I did only the cabinet.

Since I have already all the components, I will finish one speaker and test it and post the result.

I will use it for learn.

cheers

The main thing you will learn is that the models you posted are correct.

One of your huge problems is that you do not have a woofer, but a high sensitivity mid/bass driver.

That speaker won't have a lick of true bass. The sealed size is a quarter cu.ft and the ported size is 0.65 cu.ft. Sealed F3 is 125 Hz, and ported 70 Hz.

Your enclosure is far too big for that driver, which will compound the problem.

By all means build it. You will at least learn that the major part of the problems you find after the build are already predicted. I listed a good number of them in my PM.

 

[GranteedEV]

You have selected an aluminum diaphragm tweeter with a break up mode well in the audible range. This is a common fault of this class.

I think you're confusing the effects of the diffuser with dome breakup. It doesn't show any break-up until 26khz,.

That speaker won't have a lick of true bass. The sealed size is a quarter cu.ft and the ported size is 0.65 cu.ft. Sealed F3 is 125 Hz, and ported 70 Hz.

By his model, sealed size is 26L, or 0.9 cu ft. F3 is ~105hz which should be perfect for mating to a pair of quality subs.

 

[lsiberian]

I see no problem with a high FR design. You can easily pair these with a great sub and when the time comes for an upgrade move them to surround duty. My woofers don't have the greatest F3 in the world, but I have a sealed TC sounds subs that takes care of the bass duty. As long as you tune the box properly and do a reasonably competent job on the crossover you will have a good speaker. Plus during the build you will make all the mistakes you want to make on the cheap projects so you can avoid them on the reference ones. At the very least you will be better off than Bose. I think we can all agree reference projects are a lot more work then a quick build like this one.

I will suggest you get a minidsp and chip amp to help dial in the crossover before swapping in passive components.

 

[stonemarten]

Experts,

here a picture on the building progress: very close to make the drivers holes and start the measurement!

 

[lsiberian]

I suggest cutting the holes before gluing it to the box. For solid wood I suggest using some peel-n-seal with 1/2" ply on the panels to reduce resonance. You don't have to have full coverage for it to be effective.

 

[stonemarten]

Thanks Isiberian!! For the holes sure, the front baffle is "just there" for the sides reference.
Here I can't find exactly the equivalent of peel-n-seal: there is something similar, I will post a picture before buy

Cheers

 

[slipperybidness]

Thanks Isiberian!! For the holes sure, the front baffle is "just there" for the sides reference.
Here I can't find exactly the equivalent of peel-n-seal: there is something similar, I will post a picture before buy

Cheers

This is what I have used
http://www.amazon.com/gp/product/B00BWAKYIU/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

[stonemarten]

After some research, this is what I found

http://www.amazon.co.jp/dp/B003GZ8QRK/ref=gno_cart_title_0?_encoding=UTF8&psc=1&smid=AN1VRQENFRJN5

http://www.amazon.co.jp/gp/switch-language/product/B0043CP4VG?ie=UTF8&language=ja_JP

what do you think?

thanks!

cheers

 

[stonemarten]

Dear Experts,

here a snapshot of the woofer chamber with the peel-n-seal applied.

Soon I will fill in the box with the Acousta-Stuf Polyfill

Cheers

 

[stonemarten]

here some other progress pictures





Ready for the measurements!

 

[stonemarten]

Dear Experts,

finally I made the measurements. Below the results (75dB calibration, UMIK-1 mic at 1.5mt on tweeter axis):
- DATS V2
- 10 measurement on 0deg and 15deg, 5 on 60deg, averaged, done with the REW software (Original files available). Can you please let me know if a window of 2.35ms is ok, and if I can extend a little? I've already smoothed the FR with that value
I still need to calculate the Z-Offset, will post later

Can you please let me know if you see anything unexpected and if I can start to use the data for the crossover simulation?

Tweeter



Mids



Woofer



Tweeter at 0, 15 and 60 degree



Mids

 

[stonemarten]

Woofer



Impulse window (woofer test)



cheers

 

[TLS Guy]

I think it is fine to go ahead and model the crossover.

However unless you run a sub up to around 120 Hz, I'm not sure this is a speaker you will enjoy listening to. I'm certain I would not.

The woofer peak of impedance is 95 Hz in that enclosure. This is far too high. I predict the speaker will be around 12 db down at 50 Hz.

In addition there is a small secondary impedance rise at around 40 Hz, and a prolonged impulse response. I suspect that your enclosure is nowhere near rigid enough.

The bottom line is that you could have built a speaker, with a lot less resources and smaller that would be much better.

 

[stonemarten]

TLS Guy,

thanks for the feedback: do you have any recommendation on how to reduce the issue? More Polyfill? less?

The box is made by 36mm of wood, thick enough you can walk on it, the internal surface is hardened by paint and it's sealed with putty in every corner. Do you think is "leaking" air? I can make it stronger as much as I like, as long I'm sure I'm doing the right thing

thanks!

cheers