I am quite surprised myself - I expected much more peaking in the smaller boxes and more extension in the larger ones . . . So, the DSP/EQ applied was able to maintain a target curve for the smaller boxes without losing much SPL output, right?
tajanes, In looking at your pictures and testing procedures, this project reminds my of a two part article that appeared in Audioxpress Magazine (Jan 2002 and Feb 2002 issues). It was called "The Infinite Box Concept", Part 1 and Part 2, written by G.R. Koonce and R.O. Wright, Jr. They built a small box and mounted an 8" woofer on one end and then mounted several 1" or 2" thick layers of Owens Corning (OC) fiberglass, #703 and #705, on the other end. They mounted the OC in frames that were held together with long threaded rods and then sandwiched together with different size reducer plates to control the amount of aperiodic venting through the fiberglass. Just wondering if you had read this article. I don't think this is the article that you were looking for, but I thought that you might be interested in it.
@Steve_Lee said:
I am quite surprised myself - I expected much more peaking in the smaller boxes and more extension in the larger ones . . . So, the DSP/EQ applied was able to maintain a target curve for the smaller boxes without losing much SPL output, right?
No Xmax issues at this point (freq).
I’m going to push it a bit to see what more ~35 to 45Hz of the curve it can go w/o issues (and keeping a slowish rolloff). I’d like to move the rolloff curve left (upwards) 5Hz from where it is currently. It may be a big ask ???
@4thtry said:
tajanes, In looking at your pictures and testing procedures, this project reminds my of a two part article that appeared in Audioxpress Magazine (Jan 2002 and Feb 2002 issues). It was called "The Infinite Box Concept", Part 1 and Part 2, written by G.R. Koonce and R.O. Wright, Jr. They built a small box and mounted an 8" woofer on one end and then mounted several 1" or 2" thick layers of Owens Corning (OC) fiberglass, #703 and #705, on the other end. They mounted the OC in frames that were held together with long threaded rods and then sandwiched together with different size reducer plates to control the amount of aperiodic venting through the fiberglass. Just wondering if you had read this article. I don't think this is the article that you were looking for, but I thought that you might be interested in it.
I see the 2002 issues are available on CD, which I no longer have a reader, and are not offered in hard copy. I've emailed AudioXpress to see if they would be available for download / or pdf versions.
Looks very interesting, thanks for bringing this to my attention.
This is a great project. I did something similar a number of years ago but playing with vented alignments. Just did it to kill time, I think - nothing as empirical as what you are doing.
Final design I’ll be going with a two piece speaker box set-up: Bass & Mid-tw. I’ll be able to compare a 6.5 in. Audio Nirvana broad-range as the Mid-tw vs a 6.5 in. Celestion FTX0617 coax side-by-side. Both have their + & -‘s. I’m a bit more of a fan of the Beyma coax’s (in my current 3-way) with their extended tw horn and less issues with mid acting as a moving waveguide, but the single motor positioning of the Celestion has some merit. And, I luv the ‘simplicity’ of the Audio Nirvana lack of Xover in this frequency range.
Comments
I am quite surprised myself - I expected much more peaking in the smaller boxes and more extension in the larger ones . . . So, the DSP/EQ applied was able to maintain a target curve for the smaller boxes without losing much SPL output, right?
tajanes, In looking at your pictures and testing procedures, this project reminds my of a two part article that appeared in Audioxpress Magazine (Jan 2002 and Feb 2002 issues). It was called "The Infinite Box Concept", Part 1 and Part 2, written by G.R. Koonce and R.O. Wright, Jr. They built a small box and mounted an 8" woofer on one end and then mounted several 1" or 2" thick layers of Owens Corning (OC) fiberglass, #703 and #705, on the other end. They mounted the OC in frames that were held together with long threaded rods and then sandwiched together with different size reducer plates to control the amount of aperiodic venting through the fiberglass. Just wondering if you had read this article. I don't think this is the article that you were looking for, but I thought that you might be interested in it.
I’ll look for the article- thx
I’m going to push it a bit to see what more ~35 to 45Hz of the curve it can go w/o issues (and keeping a slowish rolloff). I’d like to move the rolloff curve left (upwards) 5Hz from where it is currently. It may be a big ask ???
Sunfire true subwoofer
I see the 2002 issues are available on CD, which I no longer have a reader, and are not offered in hard copy. I've emailed AudioXpress to see if they would be available for download / or pdf versions.
Looks very interesting, thanks for bringing this to my attention.
latest aVented with eq
(blue line aVented no eq 0.35ft^3 Vb)
105 Hz -2.8 gain Q 0.5, 40 Hz 4.5 gain Q 1.4, 55 Hz 0.5 gain Q 7.5
Looks like a final build with Vb ~0.35ft^3 (or a bit north) with some more work on the aVent w eq will do it
This is a great project. I did something similar a number of years ago but playing with vented alignments. Just did it to kill time, I think - nothing as empirical as what you are doing.
Final design I’ll be going with a two piece speaker box set-up: Bass & Mid-tw. I’ll be able to compare a 6.5 in. Audio Nirvana broad-range as the Mid-tw vs a 6.5 in. Celestion FTX0617 coax side-by-side. Both have their + & -‘s. I’m a bit more of a fan of the Beyma coax’s (in my current 3-way) with their extended tw horn and less issues with mid acting as a moving waveguide, but the single motor positioning of the Celestion has some merit. And, I luv the ‘simplicity’ of the Audio Nirvana lack of Xover in this frequency range.