SBS18

[apexaudio]

Serial Bandpass Subwoofer with 18 inch EVX180B driver.

 

[m R g S r]

I thought this was an SBS (systems by shorty) thread...
Anyway what's your point? The EV driver is expensive for what it is, and your design shows no details....do you want to build this?

 

[apexaudio]

I thought this was an SBS (systems by shorty) thread...
Anyway what's your point? The EV driver is expensive for what it is, and your design shows no details....do you want to build this?

I like sound of Dynacord PWH18 subwoofer and I want to DIY similar box.
Regards

 

[m R g S r]

Isn't the driver $500usd or So?
Do you have the drivers already? If not...I think that $500 will get you much further with a B&C or 18sound driver in a TH-18 or keystone....just my 2cents.

 

[apexaudio]

Isn't the driver $500usd or So?
Do you have the drivers already? If not...I think that $500 will get you much further with a B&C or 18sound driver in a TH-18 or keystone....just my 2cents.

Yes I have 4 EV drivers replaced with B&C 18TBX100 in bass reflex.

 

[m R g S r]

I've heard the dynacord cobras on multiple occasions, wasnt really impressed by them. But hey if you liked them go for it!

They're -10db at 30hz...so I'm guessing you don't care to dig that low with these? Or do you have some other sort of subwoofer to compliment these?

 

[apexaudio]

I've heard the dynacord cobras on multiple occasions, wasnt really impressed by them. But hey if you liked them go for it!

They're -10db at 30hz...so I'm guessing you don't care to dig that low with these? Or do you have some other sort of subwoofer to compliment these?

I have 2 cobra subs, but FX20 is not same as PWH18.

 

[apexaudio]

Today this sub was shaking my house

 

[apexaudio]

I change port, now is 150x100mm

 

[djk]

That's what is called a 'planar wave horn' at another forum.

The front stub adds gain peaking at its 1/4W length frequency.

The Klasko patent (expired) gives us some better ideas as far as multiple drivers and wasted space around the 1/4W stub. The area of the 1/4w stub need not be as large as the Sd of the driver (s), 70%~80% should work well.

Patent US5313525 - Acoustic apparatus with secondary quarterwave resonator - Google Patents

 

[apexaudio]

Recomanded speakers
http://bmsspeakers.com/fileadmin/bms-data/downloads/bms_catalogue_2012-03-14_72dpi.pdf

 

[bjorno]

Patent US5313525 - Acoustic apparatus with secondary quarterwave resonator - Google Patents

FYI, This approach was known and executed in designs ~20 Years before this Patent were issued,at least here in Scandinavia including the use of a referenced positive feedback to cure high Qts Driver. BTW..Here is a picture containing snip of the suggested positive amp. and others.

b

 

[djk]

5150417 is nothing like 5313525, or the Dynacord being discussed.