Hello everyone, first I will thank you for your wonderful forum.
There is a tremendous wealth of knowledge here and I hope to learn more in the future in my exploration of DIY audio. This may be noob question but I don’t quite understand all the various t&s parameters and I was wondering if some of you could assist me in some cabinet design.
I have a set of Eminence Beta CX10 Coaxial drivers with ASD1001 compression drivers and appropriate cross overs. These are drivers that I have owned for a while, I have them in cabinets that I built based on an Eminence cabinet recommendation paper. I am looking to replace the cabinets since they are ugly, it was my first and somewhat rushed attempt at speaker building. I would like to get the best performance out of these drivers that I own already. I these will be used as LCR speakers for home theatre use. I plan on having a 80hz highpass filter as they are crossed over with a subwoofer. It might not be particularly relevant but the subwoofer is a Tekton Cinema sub. Eventually when I build up some money and addition knowledge I’d like to build 4 DIY subs to place around my room.
I’m trying to optimize for sound quality and output above 80 hz. My understanding is that a higher crossover frequency effectively limits the strain on the low frequency driver which should allow for higher output.
Now on to the relevant question at hand.
From my research these drivers are better suited for ported cabs. The speakers sit behind an AT screen in my home theatre and therefore the drivers theoretically have a reasonably large volume if required. I say the exterior dimensions could be as large as 2’ wide, 5’ tall, 3’ft deep. I can’t imagine they need to be that impractically large.
I plugged my numbers into one of the automatic calculators online, I am trying to understand how the box tuning effects the cab.
No specified Fb gives me:
Vb = 1.77 ft3 = 50.21 lts
f3 = 53.44 Hz
fb = 52.09 Hz
Dv = 4 in = 10 cm
Lv = 3.8 in = 9.22 cm
If I set the fb to 80hz it gives me
Vb = 1.77 ft3 = 50.21 lts
f3 = 53.44 Hz
fb = 80 Hz
Dv = 4 in = 10 cm
Lv = -0.23 in = -0.7 cm
Does this mean I just have to make a 1.77ft3 box and cut a 4” hole in it?
Can you walk me through this stuff?
There is a tremendous wealth of knowledge here and I hope to learn more in the future in my exploration of DIY audio. This may be noob question but I don’t quite understand all the various t&s parameters and I was wondering if some of you could assist me in some cabinet design.
I have a set of Eminence Beta CX10 Coaxial drivers with ASD1001 compression drivers and appropriate cross overs. These are drivers that I have owned for a while, I have them in cabinets that I built based on an Eminence cabinet recommendation paper. I am looking to replace the cabinets since they are ugly, it was my first and somewhat rushed attempt at speaker building. I would like to get the best performance out of these drivers that I own already. I these will be used as LCR speakers for home theatre use. I plan on having a 80hz highpass filter as they are crossed over with a subwoofer. It might not be particularly relevant but the subwoofer is a Tekton Cinema sub. Eventually when I build up some money and addition knowledge I’d like to build 4 DIY subs to place around my room.
I’m trying to optimize for sound quality and output above 80 hz. My understanding is that a higher crossover frequency effectively limits the strain on the low frequency driver which should allow for higher output.
Now on to the relevant question at hand.
From my research these drivers are better suited for ported cabs. The speakers sit behind an AT screen in my home theatre and therefore the drivers theoretically have a reasonably large volume if required. I say the exterior dimensions could be as large as 2’ wide, 5’ tall, 3’ft deep. I can’t imagine they need to be that impractically large.
I plugged my numbers into one of the automatic calculators online, I am trying to understand how the box tuning effects the cab.
No specified Fb gives me:
Vb = 1.77 ft3 = 50.21 lts
f3 = 53.44 Hz
fb = 52.09 Hz
Dv = 4 in = 10 cm
Lv = 3.8 in = 9.22 cm
If I set the fb to 80hz it gives me
Vb = 1.77 ft3 = 50.21 lts
f3 = 53.44 Hz
fb = 80 Hz
Dv = 4 in = 10 cm
Lv = -0.23 in = -0.7 cm
Does this mean I just have to make a 1.77ft3 box and cut a 4” hole in it?
Can you walk me through this stuff?
Last edited:
Greets!
The 1st one says it needs a 4" i.d. pipe 3.8" long and the 2nd one gives a negative length, ergo the vent must be larger in diameter just to have a baffle thickness vent.
Regardless, 'we' did lots of designs way back when for these drivers, but for an 80 Hz XO the main choices regardless of speaker design is normally = > 80 Hz Fc sealed or best tuned to Fs vented in a tower/column (MLTL) designed to put the center of the tweeter at 2/3 screen height, so you tell us what you want/need and/or search here or the AVS forums.
BTW, what's the link? I want to make sure it's on my blacklist.
The 1st one says it needs a 4" i.d. pipe 3.8" long and the 2nd one gives a negative length, ergo the vent must be larger in diameter just to have a baffle thickness vent.
Regardless, 'we' did lots of designs way back when for these drivers, but for an 80 Hz XO the main choices regardless of speaker design is normally = > 80 Hz Fc sealed or best tuned to Fs vented in a tower/column (MLTL) designed to put the center of the tweeter at 2/3 screen height, so you tell us what you want/need and/or search here or the AVS forums.
BTW, what's the link? I want to make sure it's on my blacklist.
Link to which? I don’t think I posted anything nefarious, I tried to link to an Eminence spec page from their website. Are you recommending that I just build a sealed cabinet? What internal volume should I be shooting for given my application requirement and or do you think it’s even worth reusing these drivers or moving onto a more contemporary design?
also p.s. Nice Vott picture I have a set of model 19s in my main 2 channel rig.
also p.s. Nice Vott picture I have a set of model 19s in my main 2 channel rig.
If sealed gives you the response you require (even if it requires a little EQ down towards the xover point) this will be preferable to ported in terms of fidelity - ported enclosures store energy which has to be dissipated over time, blurring transients and reducing the signal to noise ratio, as it were. If you must go ported, try for a higher f3 closer to xover frequency as this will usually reduce group delay where it matters. A hole in the box is just as valid as a tube port, and don't be temped to make them to small or too long; a single circular port being optimum, but take care to make the port's airflow symmetrical - a simple pipe in a baffle is far from ideal.
Don't become too fixated about a few Hz of response here and there, or agonise over port length to the last mm, since the eventual response will change with time, temperature, and output level anyway!
My tiny 'pub' 10" PA speakers are only 20l, ported and flat to 80Hz but bear in mind these are designed for maximum output.
Design. Build. Enjoy! Anything we make with our own hands along with the almost inevitable blood, sweat, and tears will always 'sound better' than commercial offerings...😉
Don't become too fixated about a few Hz of response here and there, or agonise over port length to the last mm, since the eventual response will change with time, temperature, and output level anyway!
My tiny 'pub' 10" PA speakers are only 20l, ported and flat to 80Hz but bear in mind these are designed for maximum output.
Design. Build. Enjoy! Anything we make with our own hands along with the almost inevitable blood, sweat, and tears will always 'sound better' than commercial offerings...😉
Last edited:
The calculator you used; only nefarious in that it's much too simplified, i.e. negative numbers ?!
No, though while a good option due to high(er) Qts was just noting my way of viewing cab alignment choices based on my interpretation of the pioneer's musings:
Pg. 76: https://archive.org/details/HowToBuildSpeakerEnclosuresByAlexixBadmaieffDonDavis/page/n75/mode/2up
“A nagging question in the design stage of any enclosure of this type is "How large shall it be?” It was pointed out earlier that the enclosure can be too large or too small for proper bass-reflex action. This implies that an optimum volume exists and indeed it does. This optimum volume does not depend upon the size of the speaker nor its resonant frequency per se but rather on the ratio of enclosure air stiffness to the speaker cone suspension stiffness. This optimum ratio is 1.44 or, looking at it another way, the speaker resonant frequency in the enclosure before porting should be 1.56 times the free-air resonance of the speaker. This size enclosure, when properly tuned, yields at the same time the most extended low-frequency response and a transient response with subjectively unnoticeable hangover, assuming sufficient damping exists. Compared to the entirely closed cabinet, the half-power point (3 db down) occurs at 0.7 times the closed cabinet speaker resonance for an extension of one-half octave."
Already stated my guidelines for a DIY cab alignment, which require you telling us the dimension from floor to 2/3 screen height if floorstanding.
Nothing wrong with using them for your app, though of course newer, more expensive, ones will in some ways be an audible improvement, especially WRT music soundtracks in general and low level/whispering dialog in high ambient background noise, music, a major problem for seniors without hearing aids.
Thanks, actually had an L-C-R system of the single bass horn configuration back in '69-'70 where the 'C' was a derived CC, though HF horns were 'only' tar filled 805. Cool! Those make great L-C-R speakers (as I'm sure you know). 😉
Last edited:
