Welcome, Guest
Username: Password: Remember me
  • Page:
  • 1
  • 2

TOPIC:

Loudspeaker project 5 years 3 months ago #25899

  • dirkwright
  • dirkwright's Avatar Topic Author
  • Offline
  • Premium Member
  • Premium Member
  • Posts: 138
  • Thank you received: 7
I'm almost finished with my loudspeaker project using a miniDSP plate amp. The driver I'm using is the B&C 12CXN76, which is a coaxial 12" driver. After struggling with the software I think I have something that works pretty well. These plate amps are not really quiet enough for a high sensitivity loudspeaker, like a horn or this one, which is nearly 100 dB sensitive. There is hiss, but not a terrible problem.

Please Log in or Create an account to join the conversation.

Loudspeaker project 5 years 3 months ago #25901

  • dirkwright
  • dirkwright's Avatar Topic Author
  • Offline
  • Premium Member
  • Premium Member
  • Posts: 138
  • Thank you received: 7
I give up. Your image loading software does not work. I add a file, and it refuses to be inserted. I put in a url and it does not work. I give up. Have a nice day.

photos.google.com/photo/AF1QipOsTf7THJfm...D7IAwPUziDE6LJpTWc6N

photos.google.com/photo/AF1QipPrxZ8ROePg...bGmp3jADkVtTGpWa7QGw

photos.google.com/photo/AF1QipMDS34Rm9L7...W_-ZltyoVNxQEIKj_Hnl

Please Log in or Create an account to join the conversation.

Last edit: by dirkwright.

Loudspeaker project 5 years 3 months ago #25905

  • john.reekie
  • john.reekie's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 3775
  • Thank you received: 1588
The links don't work.
I am not miniDSP support.

"You must ask the right questions." - Dr. Alfred Lanning's hologram.
-> Have you read the User Manual??
-> Have you drawn and posted a diagram?
-> Have you posted a screenshot?
-> Have you posted your config file?

Please Log in or Create an account to join the conversation.

Loudspeaker project 5 years 3 months ago #25931

  • dirkwright
  • dirkwright's Avatar Topic Author
  • Offline
  • Premium Member
  • Premium Member
  • Posts: 138
  • Thank you received: 7
I'm sorry but uploading images does not work. I tried several different ways. Oh well.

Please Log in or Create an account to join the conversation.

Loudspeaker project 5 years 3 months ago #25932

  • john.reekie
  • john.reekie's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 3775
  • Thank you received: 1588
I mean the links that you posted simply don't work - they result in a 404 error. (It is nothing to do with uploading to the miniDSP server.)

Maybe you have put the images in a private album on photos.google.com? If so you would need to change a setting to make them visible to other people.
I am not miniDSP support.

"You must ask the right questions." - Dr. Alfred Lanning's hologram.
-> Have you read the User Manual??
-> Have you drawn and posted a diagram?
-> Have you posted a screenshot?
-> Have you posted your config file?

Please Log in or Create an account to join the conversation.

Loudspeaker project 5 years 3 months ago #25933

  • dirkwright
  • dirkwright's Avatar Topic Author
  • Offline
  • Premium Member
  • Premium Member
  • Posts: 138
  • Thank you received: 7
How about now?
photos.google.com/share/AF1QipOkYKzfMfNK...WVBmZ2NaRjRweGN3UWR3

photos.google.com/share/AF1QipOkYKzfMfNK...WVBmZ2NaRjRweGN3UWR3

photos.google.com/share/AF1QipOkYKzfMfNK...WVBmZ2NaRjRweGN3UWR3

FR has been improved a bit last night. It's now +/- 1dB or so from 100Hz to 10kHz. I have a smoothed curve on the other computer that I can up load.

These miniDSP amps are not really suitable for really high sensitivity drivers, since there is hiss and hum if I put my ear near the speaker. It's not a huge problem, but still, for super high end use, silence is required. Once the music is playing you can't hear it of course. But, miniDSP is basically the only game in town for this kind of plate amp as far as I know. No one has developed anything this far, so I'm basically stuck with them. The mechanical aspect of their gear is pretty bad, with stripped screws in the chassis, etc. but the electronics do work pretty well. I guess they cut a lot of corners in order to make this stuff affordable. I dunno.

Please Log in or Create an account to join the conversation.

Last edit: by dirkwright.

Loudspeaker project 5 years 3 months ago #25935

  • john.reekie
  • john.reekie's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 3775
  • Thank you received: 1588
Working now B)
I am not miniDSP support.

"You must ask the right questions." - Dr. Alfred Lanning's hologram.
-> Have you read the User Manual??
-> Have you drawn and posted a diagram?
-> Have you posted a screenshot?
-> Have you posted your config file?

Please Log in or Create an account to join the conversation.

Loudspeaker project 5 years 3 months ago #25937

  • dirkwright
  • dirkwright's Avatar Topic Author
  • Offline
  • Premium Member
  • Premium Member
  • Posts: 138
  • Thank you received: 7
Here is a 1/6th octave smoothed response as of last night, after some more tweeking. I'm very satisfied with how easy it is to alter the speakers FR. Performance of the loudspeaker is outstanding. I am hearing details in familiar music that I've never heard before, even with really great headphones. I just need to finish building the rest of the system, which will take time because I leave for a 4 week vacation tomorrow. Obviously, I built these boxes by myself by hand, including all of the veneering, the grill frame, etc. I did not expect much of any response below 100Hz, since this driver trades off sensitivity for bandwidth. It sure is strange to have such a huge satellite, but that is the consequences of high sensitivity and thus high resolution in a loudspeaker. I have also yet to build the 18" sub woofer that goes with this 2.1 system. That is also a high sensitivity driver of some 99dB and fits into a 7 cu ft vented box. Fortunately I have a gracious wife who loves music also.

photos.google.com/share/AF1QipOkYKzfMfNK...WVBmZ2NaRjRweGN3UWR3

The crossover is 48dB/octave LR @ 1.2kHz. Driver is a coaxial B&C 12CXN76 12" pro sound driver in a vented box. I used Basta! to design and fine tune the box. The only issue I have is the noise when there's no music present. Other than that, performance is really great.

One other thing that's cool about these speakers is that the dispersion of the tweeter and woofer are identical at the crossover point. They are both very close to 60 degrees, so the crossover should be seamless regardless of where you sit relative to the speaker. Also, using a sharp cutoff crossover with a coaxial speakers minimizes IM distortion. So, that's good also. I'm really happy with these so far, except for the noise.

Please Log in or Create an account to join the conversation.

Last edit: by dirkwright.

Loudspeaker project 5 years 3 months ago #25959

  • devteam
  • devteam's Avatar
  • Away
  • Administrator
  • Administrator
  • Posts: 8965
  • Thank you received: 1291
@ dirkwright

Nice speakers. :-) Did you check your jumpers for the output section? (user manual p10, bottom section) A 250W on a very sensitivity driver could be the issue here as i'm sure that you don't need much power looking at the sensitivity so you're most likely doing a big attentuation inside the DSP?. Just pad that output as a test.

DevTeam
miniDSP, building a DSP community one board at a time.

Please Log in or Create an account to join the conversation.

Loudspeaker project 5 years 3 months ago #25971

  • dirkwright
  • dirkwright's Avatar Topic Author
  • Offline
  • Premium Member
  • Premium Member
  • Posts: 138
  • Thank you received: 7
I can check that when I return from vacation in 4 weeks.

Please Log in or Create an account to join the conversation.

Loudspeaker project 5 years 2 months ago #26499

  • dirkwright
  • dirkwright's Avatar Topic Author
  • Offline
  • Premium Member
  • Premium Member
  • Posts: 138
  • Thank you received: 7
I first tried switching to the digital input and there was no change in the noise. So, I opened up the box and pulled off the two jumps as instructed to reduce amplifier output by 16 dB. I reinstalled the amp in your metal box and turned it on. Now the thermal light comes on! I turned it off, opened up the box, did an inspection and cannot find anything obviously wrong. I reinstalled the jumpers and put the amp back in the box, same result: LED #3 Thermal comes after a few seconds of turning the amp on. This is with no input or output cables connected. I tried it outside the box, same result. This amp is apparently no good! Please help.

Please Log in or Create an account to join the conversation.

Loudspeaker project 5 years 2 months ago #26551

  • devteam
  • devteam's Avatar
  • Away
  • Administrator
  • Administrator
  • Posts: 8965
  • Thank you received: 1291
@ dirkwright

This is odd indeed. It sounds like you already have a tech support ticket opened with our team. Correct? If so , no need to double our work, our tech support team will assist directly in trying to solve what is the issue here.

DevTeam
miniDSP, building a DSP community one board at a time.

Please Log in or Create an account to join the conversation.

Loudspeaker project 5 years 2 months ago #26574

  • dirkwright
  • dirkwright's Avatar Topic Author
  • Offline
  • Premium Member
  • Premium Member
  • Posts: 138
  • Thank you received: 7
Yes, I have mailed them back to you in Hong Kong. I am completely baffled as to why they do no work. I have no clue what happened. I am using them in your metal boxes and I don't know if that made a difference when I installed and removed them from the boxes. I did a careful visual inspection and did not find any disconnected wires, or any other obvious problem. I don't have a service manual so I can't do even basic things like voltage measurements. One of them has a thermal light come on a second or so after turning it on, and the other does not work at all. Oh well, I hope they can easily be fixed. Otherwise I'm out hundreds of dollars.

Please Log in or Create an account to join the conversation.

Loudspeaker project 5 years 2 months ago #26611

  • devteam
  • devteam's Avatar
  • Away
  • Administrator
  • Administrator
  • Posts: 8965
  • Thank you received: 1291
OK, we'll have a look at them once we receive them and report via the tech support ticket you already opened.

Devteam
miniDSP, building a DSP community one board at a time.

Please Log in or Create an account to join the conversation.

Loudspeaker project 5 years 1 month ago #26794

  • dirkwright
  • dirkwright's Avatar Topic Author
  • Offline
  • Premium Member
  • Premium Member
  • Posts: 138
  • Thank you received: 7
Two satellites done, subwoofer is next. Testing the system in the living room:

www.facebook.com/photo.php?fbid=10207335...51952&type=3&theater

I'm using the smaller plate amps. There's still some noise, but it's not terrible.

Please Log in or Create an account to join the conversation.

Last edit: by dirkwright.
  • Page:
  • 1
  • 2
Moderators: devteam