Lex breijs

Hello Josh,

If i recall correctly the weighing was done with the driver installed. So afterall really not bad. I live in the Netherlands. Bike systems are more and more popular here, some people just prefer openair dancing i guess. Also its easy to move when authoritys disagree. Ill probably make the ckram into a bike cart and will upload pics of it.

Unrelated question, do you know if anyone ever posted measurements of the gjallard horn #2 its very intreguing. Im considering building it aswell the ckram has gotten me appreciative of that low end information. Can you tell me how it would compare to the ckram?

Hello Josh,

8 ohm 21sw152 is the driver that i used, driven by a Powersoft Digam amplifier. The front plate looks cool and as far as i can see raises the plot a little between 40 and 50 Hz. The plip around 150Hz is no problem for me as i am testing the sub currently underneath Art Welters Syntripp's. These are crossed at 80 Hz to minimize sense of direction in the sub (not sure this is the right word but at this moment its difficult to locate the sub by ears alone). The Syntrips Themselves have a way of dissapearing (diffucult to locate blind) audibly if that makes sense. 

I am very pleased with the result i have tortured it quite little with some sub tests and there is no noises from the cabinet other then a poorly sealed speakon socket (very minimal). Building it, i made sure the front plate is not touching the cabinet on the sides.

I still have to play loud music over it but sofar to my ears CKRAM has a very clean and accurate sound, revealing a lot of information in the lowest frequencys. Deepeer modern house tracks are truly a joy, but also recent music for instance billy eilish and for instance beonce. Even at higher levels (sofar) it doesnt sound boosted like with some commercial BR designs i find.

The only minus is personal. I hoped it would be more portable. You cant have everything and to have impressive volume down to 30Hz obviously comes at a cost. For this setup to be a solo operation is not as easy as i hoped. its just a little to much weight x size, to comfortably load alone. That being said it matches the Syntrips very well i think.

As in some occasions i am looking to transport the sub by bicycle, i am considering building another smaller sub cabinet. I saw a design allegedly by you😀, wich would match my project. single 18" BR with a square port in one of the corners of the front plate. I cant find it at the moment (Diy audio forum rabbit hole syndrome). Does this sound familliar at all?

Thx again for the great drawings and calculations wich i am sure have costed a lot of attention. If there is anything that you or anybody else want me to measure or test please let me know. Currently i am using a focusrite Dac and Umic measuring mic. combined with REW.

Lex,

So.. here are some measurements with front plate installed and up to 3 ports blocked with grain sacks (quite tightly)

Measurements were done in an mostly open area, the speaker was sat on a few tonnes mill stone on some paper bags to make it very stabil. The cobble stones were too uneven. there is a highway nearby but during spl calibration the noise of the cars didnt surpasse 68 dB. the microphone was sat 360cm from te center of the cabinet.  It was sat close to ten meters away from the building wich is round so we felt that maybe it would be less visible in the measurements. Please comment on the plots so i know what to look at. And thanks again to Josh Ricci for sharing these plans

Regards Lex

ckram Dec 30 molen meting volledig.mdat

its finised.

used the best quality multiplex for this part and its absolutely rock solid. its attached with pocket screws and theres foam in between the baffle and the cabinet. will update with test results soon, when the weather turns  a bit.

Greets

heres the REW file can someone please explain what the "phase line" (dotted red) is for and what it tells us in this case?

ckram Dec 20 op hout.mdat

Hi,

Did initial measurements today to see if i have everything in place. the sweep is set 10hz to 150hz. The dsp was set 20hz to 500hz lower slope was BW12, hadnt seen youre suggestions yet. I live in a crowded place close to airport and highway. The measurement is too close to a building+-5 meter and my neighbours camper. Before the sweeps i tried some youtube bass tests on different frequencys searching for rattles but it is sofar very quiet. I may continue (weather allowing) tomorrow and set the DSP to your suggested settings. I used a firefly as a DAC and UMIK1 as microphone. Software is REW. Im very much open to interpretations and adjustment suggestions for the next measurements.

greetings Lex

small update,

Added much needed grips and a couple simple corners. Also connected the speakon input using 6mm2 wires. Was gonna do some initial testing first and then complete the design with the front disk. Does anyone have some recommendations for setting the DBX drive rack im using? low cut off frequency aswel as top  cut off point. As an amp i have the Powersoft Digam 7000. 

thanx in advance

Thanks

Ill post more pics once i i get to it, and will upload measurements once im finished!

Regards Lex

Using economy style plywood and some scraps for the 12mm parts i started construction here are some pictures of the process.

First off thank you Josh the drawings are flawless!

Sadly upon reaching this point my work shift starts again so will continue with the circular bit once i get back home. sofar everything is up to the millimeter exactly as drawn.

Upon completion i would like to submit measurements. I think i have everything (software, calib. mic., mic, stand etc) Could anyone point me in the right directions on a step by step measurement process?

I know theres a big chance this thread is dead, no one will be reading this but im trying anyway and like to thank Josh again for the nice drawings.

Greetings Lex Breijs.

Hello,

New to the forum, impressive stuf !! searching the different forums for a compact somewhat light enclosure with max output for a sound system operated outside and bike mounted (Dutch people.....). Am i correct in concidering the ckram for this purpose, or can more knowledgable people on this forum direct me in the right way. Also, are the plans for the ckram yet available in any cnc or cnc transferable format?