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Old 31st August 2019, 08:26 AM   #11
audfrknaveen is offline audfrknaveen  India
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Thanks for sharing !!! This application note is useful
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Old 31st August 2019, 08:46 AM   #12
mart34 is offline mart34  England
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Thanks, I've read the application note before, very informative. I've treated my design like a numbers game, and have designed for flat response down to 20Hz. How this performs "in room" with room gain, will be interesting to see once I'm able to afford a calibrated mic. My main goal was for flat response over the audible range (down to 20Hz), primarily for electronic music, and secondary to that - also for movies.
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Old 31st August 2019, 09:00 AM   #13
audfrknaveen is offline audfrknaveen  India
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Good to know !!!
What do you use to boost the low frequencies ???
Something like mini DSP ??
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Old 31st August 2019, 09:37 AM   #14
mart34 is offline mart34  England
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Quote:
Originally Posted by audfrknaveen View Post
Good to know !!!
What do you use to boost the low frequencies ???
Something like mini DSP ??
I'm not planning on boosting anything, the design is such that the response is flat in the audible range. Ported designs cant compete with sealed for subsonic extension, and I cant boost in the subsonic range due to mechanical limitations of the ported designs. Plan is to use a minidsp parametric equalizer to tune out room modes, but this would typically involve attenuating the peaks in frequency response caused by the room, to eliminate the boominess which is an unavoidable consequence of achieving flat response to the lower end of the audible spectrum. This will be once I get a microphone and use with REW.
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Old 31st August 2019, 04:25 PM   #15
Jag768 is offline Jag768  Netherlands
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Quote:
Originally Posted by mart34 View Post
Thanks. 8 XLS 10" sounds rather impressive, do you have any photos / threads on your build? would be great to see that.

Regarding the Minidsp 2x4 HD, that's the first I've heard about filtration issues - do you have any further specifics about the issue so I can research online? Reason I'd considered the HD is due to the Digital Input which I need since my source is digital, and the fact it has a higher output voltage - 2V I believe. The standard minidsp only has max 0.9V. The crown XLS has two input sensitivities - 0.775 and 1.4V, but I'm still concerned I wont have the Vout to maximise the crown gain.
Here is the build thread. I started doing a cardiod sub experiment, ended up using 4 monopoles (sealed dual xls10), optimized using MSO.

About choosing hd or non-hd, here's more info
AVSforum thread on the subject
MSO creator's take
Measurements showing unwanted LF filter behaviour
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Old 31st August 2019, 05:09 PM   #16
Entas is offline Entas  Lithuania
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So non-HD version is better to use if i want to filter low frequencies at this point subwoofer?
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Old 1st September 2019, 10:14 AM   #17
mart34 is offline mart34  England
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Quote:
Originally Posted by Jag768 View Post
Here is the build thread. I started doing a cardiod sub experiment, ended up using 4 monopoles (sealed dual xls10), optimized using MSO.

About choosing hd or non-hd, here's more info
AVSforum thread on the subject
MSO creator's take
Measurements showing unwanted LF filter behaviour

Wow, that's a ridiculously impressive build, would be great if you could put a video on YouTube!

Thanks for all the detailed links on minidsp. That was all totally new to me, I'm surprised this doesnt get mentioned more on forums and reviews of the HD version. Clearly there is a high risk I wont be able to accurately set a subsonic high pass filter, which is too risky due to the potential mechanical damage of my drivers. So, minidsp 2x4 (non HD) it is for me. One of your links even mentioned that the output voltage just has to be higher than the fed amplifiers maximum voltage in, so the minidsp 2x4 output voltage of 0.9V is good for the Crown XLS series 2 maximum input voltage of 0.775V.

Thanks very much
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Old 1st September 2019, 10:16 AM   #18
mart34 is offline mart34  England
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Quote:
Originally Posted by Entas View Post
So non-HD version is better to use if i want to filter low frequencies at this point subwoofer?
My interpretation is that although you have the ability to set filters / EQ down to 10Hz, the closer you get to 10Hz the more inaccurate the filters/EQ will be, and not by just a minor amount but it could potentially be substantially inaccurate.
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Old 6th September 2019, 02:51 PM   #19
Jag768 is offline Jag768  Netherlands
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Quote:
Originally Posted by mart34 View Post
Wow, that's a ridiculously impressive build, would be great if you could put a video on YouTube!

Thanks for all the detailed links on minidsp. That was all totally new to me, I'm surprised this doesnt get mentioned more on forums and reviews of the HD version. Clearly there is a high risk I wont be able to accurately set a subsonic high pass filter, which is too risky due to the potential mechanical damage of my drivers. So, minidsp 2x4 (non HD) it is for me. One of your links even mentioned that the output voltage just has to be higher than the fed amplifiers maximum voltage in, so the minidsp 2x4 output voltage of 0.9V is good for the Crown XLS series 2 maximum input voltage of 0.775V.

Thanks very much
Im not really into making youtube movices but thank you . Actually building 4 sealed subs was no rocket science, just a lot of work . Getting all 4 subs to produce flat response at multiple listening positions was the hardest part. But if you spend a lot of time in MSO, you always get it right .

Quote:
My interpretation is that although you have the ability to set filters / EQ down to 10Hz, the closer you get to 10Hz the more inaccurate the filters/EQ will be, and not by just a minor amount but it could potentially be substantially inaccurate.
Thats right. And the problem is that the filters start "peaking". However, i can't find any measurements on the HD version of the miniDSP, which is different from the 4x10 version. So i don't know if this issue relates to the miniDSP HD version. But if input sensitivity is not an issue, i would get the regular version anyway.
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Old 7th September 2019, 09:37 PM   #20
mart34 is offline mart34  England
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Join Date: Jul 2004
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Quote:
Originally Posted by Jag768 View Post
Im not really into making youtube movices but thank you . Actually building 4 sealed subs was no rocket science, just a lot of work . Getting all 4 subs to produce flat response at multiple listening positions was the hardest part. But if you spend a lot of time in MSO, you always get it right .


Thats right. And the problem is that the filters start "peaking". However, i can't find any measurements on the HD version of the miniDSP, which is different from the 4x10 version. So i don't know if this issue relates to the miniDSP HD version. But if input sensitivity is not an issue, i would get the regular version anyway.
Totally understand, not everyone wants to put their life on YouTube. I bet is was very hard work, I'm struggling to find the time to make a single enclosure, let alone four !Thanks again for the feedback, appreciated.
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