Bass reflex design for PM6C?

[juanito]

Has any body got a design with a bass reflex tipe of enclosure for the Lowther PM6C? Can it be done with WinISD? I tried with this software and it is not included. Also I tried to add the parameters but I miss some from official lowther web site, so I can't simulate either with WinISD. Has any body tried with winISD and Lowther PM6C??
Thanks in advance.

[MJK]

Measured T/S parameters for Lowther drivers can be found on my site.

http://www.quarter-wave.com/General/Lowthers.pdf

There is also a ML TL enclosure design that will work with the PM6C. Make sure you use a BSC filter to even out the rising SPL response.

Martin

[juanito]

Thanks Martin, but do you know why are these parameters diferent to thes others:
BD-Design - Thiele-Small parameters Lowther C-Series
http://www.lowtherspeakers.com/c.jpg
The Lowther PM6C Drive Unit
There are all diferent between them...

[MJK]

The first two links are the standard T/S parameters from Lowther, they are wrong. The third link may be actual measured values since they are closer to what I measured.

I think the foam surround and spider on Lowther drivers makes the unit to unit variation fairly high. If you are going to buy Lowther drivers make sure you have the capability to measure the T/S properties before designing an enclosure.

Lowthers are great drivers but the buyer/user needs to be careful and technically savvy to get the best results from a pair.

Martin

[juanito]

Some how the WinISD doesn't work either. I fill the T/S parameters, then the electrico mechanical parameters (some of them) and it gives error. There is no way I can go any further. Also is sodificult, if not impossible, to find a bass reflex design wich should be easy... aiiah! There is a guy selling a pair of PM6C here and I would only get them if there is a simple box design for them. Otherwise I'll may go for Fostex FE167E.

[MJK]

I have never used WinISD so I cannot comment. My measured properties are consistent, did you try them. Maybe a different freeware program would work better.

There is a world of difference between Lowther and Fostex drivers. If you can get the Lowther drivers to work you will be amazed. Fostex drivers are very good but are not Lowthers.

Martin

[juanito]

I've just done it with a beta version of winisd, and it will give me a box of 28,3 litres, vented with 5 cm diameter and 8 cm depth. Of course if parameters are OK!! I'll try and upload an image of parameters with WinISD.
By the way, wich other software do you know?

[juanito]

Hope you can see it!! This is how I introduced the parameters.

[juanito]

This is waht it says from Lowther Korea for the acousta 90, wich is more or less a 35 litres bass reflex box, given the mesuremets from that link.
Impedance

[rjbond3rd]

Originally Posted by juanito

By the way, [to MJK] wich other software do you know?

Martin has made his own software (and generously allows people to license it):

MathCad Computer Models : Upgraded Versions

Whereas WinISD is a box calculator (not really a simulator), Martin's software models a very large number of factors, for example the box's internal geometry, the exterior geometry (e.g., baffle width), floor bounce, wall and ceiling boundaries etc.

But Martin's software -can- definitely model simple boxes. When you are ready to move off WinISD, his software will let you start accounting for additional factors as you are ready, e.g., baffle step, distance from the listening position, toe-in, placement in the room, etc.

If you don't want to -design- a box, then as Martin suggested, check out this design of his (it's a simple build, and has vastly better bass than a bass reflex as long as you do the circuit):

Enclosure Design and Construction for the Lowther DX Series of Drivers