@mikessi I wonder if they also use a different polymer for the surround vs diaphragm. The impedance curve is awfully clean with just one primary peak at Fs, but hopefully its not over smoothed like many companies do. The HF108 is also capable of going under 1k with a steep slope and still remaining clean. I have one in an Eminence 12" neo coax crossed @ 900 hz. It sounds pretty nice, even when its louder.
Alot of these big diaphragm 1" CDs can really go low. I look for the ones that really do well under 1k to adhere to my midband integrity protection scheme.
The CDX1-1430 is for example excellent over 3k on a nice small seos horn. Thats good for a hotter dome mid to pair up with. I wonder how good the $30 Hivi DMB-A is in a WG?
Alot of these big diaphragm 1" CDs can really go low. I look for the ones that really do well under 1k to adhere to my midband integrity protection scheme.
The CDX1-1430 is for example excellent over 3k on a nice small seos horn. Thats good for a hotter dome mid to pair up with. I wonder how good the $30 Hivi DMB-A is in a WG?
I was able to purchase a pair of these domes from Playback Distributions. They only had one pair. I bought the pair. These are the ones in their newer PMC hifi speakers
@profiguy -- from the audioXpress test bench:
Features for the SB Audience 44CDN-PK include a 1” throat exit designed for use with 1” horns, a 44.3mm (1.75”) diameter voice coil wound with flat copper-clad aluminum wire (CCAW) on a high temperature Kapton non-conducting former driving a single piece PEEK diaphragm and surround (Photo 2). Other features include a FEA-optimized neodymium (neo) ring magnet motor structure, a cast-aluminum damped rear chamber, a 60W AES power handling rating (120W maximum power handling defined 3dB over nominal), a 1.8kHz recommended crossover frequency (with a minimum 12dB/octave high-pass network), an annular phase plug design, and a 1W/1m 109dB sensitivity.
Features for the SB Audience 44CDN-PK include a 1” throat exit designed for use with 1” horns, a 44.3mm (1.75”) diameter voice coil wound with flat copper-clad aluminum wire (CCAW) on a high temperature Kapton non-conducting former driving a single piece PEEK diaphragm and surround (Photo 2). Other features include a FEA-optimized neodymium (neo) ring magnet motor structure, a cast-aluminum damped rear chamber, a 60W AES power handling rating (120W maximum power handling defined 3dB over nominal), a 1.8kHz recommended crossover frequency (with a minimum 12dB/octave high-pass network), an annular phase plug design, and a 1W/1m 109dB sensitivity.
If one intends only ever to play up to 95dB or so, maybe 100dB absolute peak, what's the lowest 2nd order point you would recommend for the d7608 with the rear chamber you've been working on? I just made payment for some woofers I hope to mate mine with, and am looking forward to starting to play with them
@mikessi I did two prints of the D7608 chambers out of ABS. They weren't pretty due to weird settings with new filament I previously haven't used, but functional. I took pictures before I stuck them in the small test boxes I made for my son's monitor project and for some reasons I couldn't find them in my phone, but the original chamber design worked well. At least I'll have those measurements once I transfer the whole folder from the laptop.
@stv I'd say its ok to post the files on here for people to print from. The design is close enough to print unmodified as long as the infill ratios are high enough. 50 - 60% is probably more than enough for adequately stiff walls. Might be a little resonant for standard PLA depending on grade. Printing it inverted (open side up) is likely the orientation that will yield the lowest print time. You will need to tweak the inside ID to fit exactly on the D7608 motor. I don’t recommend extending the inner center post of the back toroidal shape so that it touches the motor. I'd use a good quality contact adhesive to attach the chamber around the inner ID to motor edge so it can be removed later. You can also attach the chamber to the enclosure opening for the mid. Id personally do the later, as its a bit simpler to make dampening changes on the fly, not needing to be constantly re-glued.
People can post questions in the D7608 thread or here, but its probably more organized and logical to have it in the specific D7608 thread.
The lowest cutoff for the D7608 with a basic LR2 or BW2 filter is 600 hz for acceptable lower mid output / THD ie. 100 dB max in room SPL for the stereo pair. It will also depend on the mid's distance to floor, walls, speaker baffle width, crest factor and overall EQ the music was treated with. I can't overemphasize how much a wide baffle will reinforce the lower mid output.
Anyone who uses the design, please dont share or host the files outside of these forums. You're welcome to augment or adapt the design for your own personal needs but please don't repost a changed file without asking me first. This is to avoid any confusion.
Please feel free to post all measurements and other details of your build using the D7608 on here if you so wish. I just ask that the chamber model files aren't used commercially for profit.
Again, I'd like to thank stv for his time and efforts in getting this done for us.
@stv I'd say its ok to post the files on here for people to print from. The design is close enough to print unmodified as long as the infill ratios are high enough. 50 - 60% is probably more than enough for adequately stiff walls. Might be a little resonant for standard PLA depending on grade. Printing it inverted (open side up) is likely the orientation that will yield the lowest print time. You will need to tweak the inside ID to fit exactly on the D7608 motor. I don’t recommend extending the inner center post of the back toroidal shape so that it touches the motor. I'd use a good quality contact adhesive to attach the chamber around the inner ID to motor edge so it can be removed later. You can also attach the chamber to the enclosure opening for the mid. Id personally do the later, as its a bit simpler to make dampening changes on the fly, not needing to be constantly re-glued.
People can post questions in the D7608 thread or here, but its probably more organized and logical to have it in the specific D7608 thread.
The lowest cutoff for the D7608 with a basic LR2 or BW2 filter is 600 hz for acceptable lower mid output / THD ie. 100 dB max in room SPL for the stereo pair. It will also depend on the mid's distance to floor, walls, speaker baffle width, crest factor and overall EQ the music was treated with. I can't overemphasize how much a wide baffle will reinforce the lower mid output.
Anyone who uses the design, please dont share or host the files outside of these forums. You're welcome to augment or adapt the design for your own personal needs but please don't repost a changed file without asking me first. This is to avoid any confusion.
Please feel free to post all measurements and other details of your build using the D7608 on here if you so wish. I just ask that the chamber model files aren't used commercially for profit.
Again, I'd like to thank stv for his time and efforts in getting this done for us.