stupid polarity question.

[Artmaster]

Originally posted by BillFitzmaurice


I have no idea what he means by that either. Sounds like a line from 'Star Trek' to me: "More power to the shields, Scotty, and modulate the phase frequency!"

ok. no problem. should you understand what means "phase" control on the picture - let me know, I'll be able to show you some more scheme.
however, if you can't hear effect of phase - something wrong.

[Learnincurve]

Hey, Nice schematic! Do you have a .pdf of that, or an eagle project or whatever. Would be good for the coillection.

I see you maths folks were kept busy last night. It makes me wish I'd paid attention in school. I can just about follow it on paper, but how to actually apply it is, and will remain a mystery, I'm glad some of you know what it means.

I'd like to thank yopu all for your time and patience. Unfortunately a combination of SAF and finance are putting a stop to this entire project. In order to do what I want I need a driver (drivers) that will work at under Fc in a tiny box (around 1 cu.ft.). They just cost too much. So despite having the silicon and the will it will just have to wait. I may pass the time by building the electronics to control the signal and hope for better econoimy later.

Cheers!

[Artmaster]

ok. forget it Learnincurve.
it's just nuance. DIY user have lot of it

but formulas: money- quality cut down our desire often... it's pity.

I'm always produced just what you want. subwoofers 27 litres inside. see the picture in my homepage.
should you need some consult - I'm always ready for you.
sorry my English

[Learnincurve]

Hey Yury, that looks really great. So small = very high WAF value!!

I just wish I had the money for one. Tell me what the passive version costs, without finish (just plain MDF) When I have the money that's just what I'm looking for.

my mail= marius@schrecker.org

[Artmaster]

I'm not sure about passive version. do you mean wothout ampl and crossover?
I think it is.
unfortunately - it's won't work...
I'm meaningly cut of range of waves about 80Hz. couse that sub have to work with front loudspeakers, you can see it too there and they have 60-20000 range as well.
marble - for the best damping factor and for silent box.
I have MDF version, wich I use for modelling difference design of sub box. it's working almost the same like marble one.....
almost..... it's "almost" take lot of money for my customers
but they are happy. they get nice, exclusive element of interior.

so, you can make it easy, using wood, or MDF of course, but in that case you need calculate box according the driver.
port system make easy way for small box and low resonanse of system. therefore - I make it ported.

[Learnincurve]

I understand. The reason I say passive is that I already have amp. Up to about 800 watts into 4 Ohms (seen because of bridge mode), and acoustic correction circuit: http://www.marchandelec.com/wm8.html. I will of-course cross over at a good frequency (posssibly 40 Hz = -6dB of main pair) possibly 60 with matching high pass for main pair. I wil never have the money for "exclusive finishes" and anyway they wouldn't look right in our old-fashioned house, so ordinary MDF is better. I was staying away from ported designs because of chuffing. How do you avoid this?

Cheers!

[Artmaster]

I see. it's ok.
let's make MDF box.
I use simple formulas for port system:
L=(2354*D^2/VF^2)-0.85D
L - port length (cm)
D -port diam (mm)
V - box capacity (litres)
F - tuning frequency (Hz)
and make more exact then. it's very depend of driver.
I consider "Onken" design are very interesting. do you know it?
probably you'll get result easy. hardly made a mistake

[Learnincurve]

No, I don't know Onken. What drivers do you use?

I still prefer the idea of a high pressure sealed box, and driver that will take a lot of watts like in http://sound.westhost.com/project48.htm

but I think economy and size restrictions will force me to use a ported box.

If I asked you to supply a kit with a MDF box, port and driver what would it cost?

[Artmaster]

unfortunately I don't sale parts. but I'm sure - you'll buy it in your sity

[Learnincurve]

Thanks for your help. I'll let you know if i decide to build a ported enclosure, perhaps you wouldn't mind giving me some more help then. Will look a little more at servo assisted mini-sealed variants first. See you around.