Visaton W170S/8 in a 64L box

[mcl2k6]

Hello all,


I had been doing some tinkering with Boxsim, to try to improve my current W170S/SC10 setup, and came up with the following:


- 64L bass reflex box,

- tuned to 30Hz
- xover at 2kHz;

- SC10N tweeter

I was wondering to get a couple of pieces of MDF in this weekend, and build the coffin.
My question would be: although Visaton already doen't recommend such large boxes, by the graphs it seems to be OK. Would it make sense to even build a prototype, or it is already too large for the W170S?


Ah, and also there is another idea to reinforce the tweeter at low frequency: I have some Monacor WG-300 waveguides, which fit perfectly to the SC10N. With a small modification (filing down around 5mm from the neck), it can be assembled quite well on the tweeter, and it even matches the W170S nicely. There was a whitepaper done by some guys, with some measurements, and it shall yield about 5dB between 2kHz and 3kHz.
This is the whitepaper: https://www.kirchner-elektronik.de/upload/15522388-Photo-Story-OK-eng.pdf


Thanks!

 

[mjf]

what is your current w170s/sc10n setup?

imho visaton itself uses the w170s in 30 liter boxes or sowhat........

 

[mcl2k6]

what is your current w170s/sc10n setup?

imho visaton itself uses the w170s in 30 liter boxes or sowhat........

It's presented in this: Visaton system - what is wrong here?
and this: Advice on Visaton configuration


The crossover is absolutely the same as from the prototype above.



Basically it's ~38L, tuned to 39Hz or so. On the 2nd thread I have done some ARTA measurements.

 

[Lojzek]

This woofer is best placed in a sealed cabinet, a larger one.

 

[mcl2k6]

So I've completed the prototype box, and done some rudimentary measurements with Arta. First graph is taken from 1m, mike centered on the area between the woofer and the tweeter, the second one is a near field measurement (5mm) from the woofer dust cap.
I've installed a Monacor WG300 waveguide on the tweeter.

 

[mcl2k6]

An here is a comparison between my old box and the new one.

 

[giralfino]

Looking at the nearfield graph, your reflex box doesn't work as expected.

Ralf

 

[mcl2k6]

Looking at the nearfield graph, your reflex box doesn't work as expected.

Ralf

Yes, that is right. I think I have failed bigtime with this box 🙁

The volume is just waaay to big for the W170S. Before dismounting it, I'll try to reduce the volume. Luckily I've assembled it in such way, that the bottom of the box can be pushed upwards rather easily, only need to take out some of the bracing I've added.
I'll try with a couple of values from 40L way down to only 25L.
I'll move the BR port up too.

 

[Lojzek]

I guess Ralf's objection had to do with the lack of reduction in spl at Fb or perhaps not. Try to measure W170s TSP yourself, if you haven't already. My speaker unit had TSP in the range of Vas=35 litres and Qts=0.7.

 

[giralfino]

I guess Ralf's objection had to do with the lack of reduction in spl at Fb

Exactly.

 

[Lojzek]

Ok, then it was probably a wrongly chosen time window or the vent was blocked with stuffing, who knows.

 

[mcl2k6]

Before dismissing the box, I've done an experiment: I've installed a ported separator at about 300mm from the bottom of the box. This means the box is split in two, a 42L enclosure and another, about 17L. Both have each a 60mm port, the separator panel also has a 60mm port.

At first it sounds interesting, there is a really solid bass. Tomorrow I'll try to measure it, and see how it performs.
Later on I've found the concept in Weem's speaker building book. It's called double chamber reflex system (DCR). He states, that the bigger volume should be two times the volume of the smaller one.

 

[mcl2k6]

A question: if I have a 60mm port on the baffle only, without a duct, and the material thickness is 18mm, that means I have a 18mm long bass reflex port?

 

[mjf]

.......yes, 60mm diameter and 18mm long bass reflex port

 

[mcl2k6]

Finally managed to measure the box.
This way the reflex system seem to start to work.