Double Chamber Reflex info?

[bill poster]

My (basic) understanding, if correct, is that the cabinet size remains the same as a standard BR (for the chosen driver) but is split in two parts, the driver in the larger cavity (roughly two thirds); both cavities are ported with the third port joining each. Not sure if all ports are the same size/length or how to calculate ..


Looking for any info or designs to understand better and also if their advantages include extra sensitivity or bass extension

thanks

[Æ]

Re: Double Chamber Reflex info?

My (basic) understanding, if correct, is that the cabinet size remains the same as a standard BR (for the chosen driver) but is split in two parts, the driver in the larger cavity (roughly two thirds); both cavities are ported with the third port joining each. Not sure if all ports are the same size/length or how to calculate ..


Looking for any info or designs to understand better and also if their advantages include extra sensitivity or bass extension

thanks

The best articles on Double Chamber Reflexes appeared in Speaker Builder Magazine. There was an Australian, Paul Sechi if I remember correctly who thoroughly analyzed and modeled the design. Yeah, he was able to get 20 something Hz from a 6.5 inch woofer, but it required a washing machine sized enclosure.
I consider it to be a dead end design.

[Chris Roemer]

Re: Double Chamber Reflex info?

Wolf's got a TB W3 (in the Showcase I believe) that uses a double chamber. I think the 1/3 - 2/3 volume split is correct, and I also think all 3 vents are the same dims.

[Jeff B.]

Re: Double Chamber Reflex info?

These don't really extend any deeper than a standard vented box of the same overall size, but what you do gain is more control of the driver's excursions and lower overall distortion due to the ports controlling the cone over a wider bandwidth.

[MGrant1957]

Re: Double Chamber Reflex info?

you are essentially correct. Design a ported box with 2 ports, split the box into 1/3 and 2/3s volume. most usually put the driver in the larger section just because it has more room. make an extra port the same size as called for in the 2-port original box to connect the 2 chambers. This design will help reduce cone excursion in the upper passband of the woofer as the smaller chamber resonance increases loading. at the lower end both champers act as a single larger volume and tune the box to the lower freq. This type of design is usually used to control cone movement at the upper tuning freq. but also has the effect of decreasing distortion in that region as well.

[Æ]

Re: Double Chamber Reflex info?

These don't really extend any deeper than a standard vented box of the same overall size, but what you do gain is more control of the driver's excursions and lower overall distortion due to the ports controlling the cone over a wider bandwidth.

Yeah, you cannot break the laws of physics. If you want to tune it lower, you'll have to build it bigger.

[bill poster]

Re: Double Chamber Reflex info?

Ah! also found a Tech Talk thread from 2013, gives great info http://techtalk.parts-express.com/sh...php?236975-Dcr

edit just spotted this book by Paul Sechi from 1992

https://books.google.co.uk/books/abo...AJ&redir_esc=y

[donradick]

Re: Double Chamber Reflex info?

Claudio Negro has a good DCR article here:
http://www.claudionegro.com/ (Projects -> Speakers -> Dual Chamber Reflex)

I built a DCR MTM with the SB13:


IMHO, it's not hard at all to divide a particular volume into 2/3 and 1/3 sub enclosures, but it can be "interesting" to fit in
all the ports without running into something. I like the design concept - seems like the bass is a bit better controlled.

Hope this helps!

[Wolf]

Re: Double Chamber Reflex info?

http://micka.de/org/en/4kammer2chassis_en.php

You can model pretty much whatever you want here^^^.

Chris- I have a W3-517S1 DCR project in the 'bucket, and a W4-1337 3CR ('3CR-Ti') project in the showcase.

Later,
Wolf

[bill poster]

Re: Double Chamber Reflex info?

http://micka.de/org/en/4kammer2chassis_en.php

You can model pretty much whatever you want here^^^.

Chris- I have a W3-517S1 DCR project in the 'bucket, and a W4-1337 3CR ('3CR-Ti') project in the showcase.

Later,
Wolf

Thanks Wolf, much appreciated. I modelled the 5" satori - around 7 litres and 57hz tuning - The biggest problem is trying to fit the bloody ports in ! they only fit if max 1.25 inch diameter. Not sure if thats enough..

[donradick]

Re: Double Chamber Reflex info?

Thanks Wolf, much appreciated. I modelled the 5" satori - around 7 litres and 57hz tuning - The biggest problem is trying to fit the bloody ports in ! they only fit if max 1.25 inch diameter. Not sure if thats enough..

Fitting the ports in is my main problem with DCR designs!

[Chris Roemer]

Re: Double Chamber Reflex info?

I've heard "capable" 5"ers (which I'd assume that Satori IS) chuff w/1.75" id ports. Rounding over the exits can help some.

[bill poster]

Re: Double Chamber Reflex info?

I've heard "capable" 5"ers (which I'd assume that Satori IS) chuff w/1.75" id ports. Rounding over the exits can help some.

is that a single or double port BR? I was hoping that with a DCR having two external 1.25" ports it may be borderline ok

[Jeff B.]

Re: Double Chamber Reflex info?

is that a single or double port BR? I was hoping that with a DCR having two external 1.25" ports it may be borderline ok

Unless you plan to drive it with a lot of power, two 1.25" ports should be fine.

[bill poster]

Re: Double Chamber Reflex info?

Unless you plan to drive it with a lot of power, two 1.25" ports should be fine.

Thanks Jeff. Now thinking a slotted port is a better solution and less clumsy looking, as I can maximise the length (and therefor the vent area) along the top and bottom of the cab; in this case exiting at the rear. And as the cab dimensions are taller than deep, I can run the internal vent up the back.. fingers crossed it will fit

Am I right in thinking slot ports chuff less the circular ports?