1. Just move the 4'x4' off-center some in your design (toward one of the four corners of the total baffle, but only part-way). If you move it toward one of the bottom corners then use pillows on the floor near the bottom of the baffle and toward the mic.. (I think at one time I had about 10 really cheap poly-filled "queen" pillows I bought from a discount store for this). Also consider compensating with the baffle height OR make the whole baffle assembly lower off of the floor and move the 4'x4' baffle toward one of the upper corners with the driver on the baffle about equidistant between floor and ceiling. (..several ways to do it, it's just up to you.)
2. the t.amp PM40C – Thomann België
3. I wouldn't/haven't worry about the *noise floor unless you have an added temporary source of sound (..someone talking, phone ringing, etc.), if that sort of sound happens during the measurement: start over. (After calibration) Set the mic distance and gate properly for the upper freq. bandwidth as per the manual. For lower freq.s it should be in the extreme near-field and then compensated after measurement for the correct db for your 2.83v measurement. Again:
http://www.ti.com/lit/an/slaa641/slaa641.pdf
*let the software do its "magic" - just make sure you avoid reflections for the gated/windowed measurement (or are in the extreme near-field for your mic.).
2. the t.amp PM40C – Thomann België
3. I wouldn't/haven't worry about the *noise floor unless you have an added temporary source of sound (..someone talking, phone ringing, etc.), if that sort of sound happens during the measurement: start over. (After calibration) Set the mic distance and gate properly for the upper freq. bandwidth as per the manual. For lower freq.s it should be in the extreme near-field and then compensated after measurement for the correct db for your 2.83v measurement. Again:
http://www.ti.com/lit/an/slaa641/slaa641.pdf
*let the software do its "magic" - just make sure you avoid reflections for the gated/windowed measurement (or are in the extreme near-field for your mic.).
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Thanks a lot for the quick response there ScottG
1. Ok I think I understand what you explained there, basically don't make it symmetrical like I did but still keep the driver at the center of the vertical axis between floor and ceiling.
2. Excellent didn't know that existed, thanks for the link I ordered it.
3. Ok clear, that document link is going to help me a great deal, just one more thing to make sure, I have read that I should not connect the driver to the amp speaker output with a multimeter on it, but at the same time I see it done often, is there a risk for one of the components ? (Tacklife DM10 Digital Multimeter)
1. Ok I think I understand what you explained there, basically don't make it symmetrical like I did but still keep the driver at the center of the vertical axis between floor and ceiling.
2. Excellent didn't know that existed, thanks for the link I ordered it.
3. Ok clear, that document link is going to help me a great deal, just one more thing to make sure, I have read that I should not connect the driver to the amp speaker output with a multimeter on it, but at the same time I see it done often, is there a risk for one of the components ? (Tacklife DM10 Digital Multimeter)
..USB mic.s have sensitivity calibration files (which necessarily includes the adac): effectively making them spl-meters, of course the down-side is that you don't have loop-back for sys. noise reduction (which is particularly important for non-linear distortion measurements).
REW uses spl-meters for NON-USB mic.s:
Calibrating the SPL Reading
but note this:
REW (Room EQ Wizard) - BillFitzmaurice.info
-in any event, for your purpose it probably isn't that relevant: instead you are concerned with differences among your measurements for on & off-axis ASSUMING ALL MEASUREMENTS ARE DONE UNDER THE EXACT SAME CONDITION (excepting of course the axial change for the mic.).
REW uses spl-meters for NON-USB mic.s:
Calibrating the SPL Reading
but note this:
REW (Room EQ Wizard) - BillFitzmaurice.info
-in any event, for your purpose it probably isn't that relevant: instead you are concerned with differences among your measurements for on & off-axis ASSUMING ALL MEASUREMENTS ARE DONE UNDER THE EXACT SAME CONDITION (excepting of course the axial change for the mic.).
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Also note this update to REW:
https://www.diyaudio.com/forums/software-tools/307910-vituixcad-103.html#post5743491
https://www.diyaudio.com/forums/software-tools/307910-vituixcad-103.html#post5743491
Thanks, good procedures there too
I am not sure to understand well that part
If making measurements with a microphone select the Mic or Z Weighted SPL Meter option. If making measurements using an SPL meter as the microphone set the meter to C weighting and select the C Weighted SPL Meter option. Set the meter range to suit the measurement level used in the check levels process (the 80dB range is recommended for the Radio Shack meter
When I play any level the REW with EMM6 show a value and then I take another reference to confirm that the level is right with the probably inaccurate and bad idea but an app on my android phone.
I don't know if this is a lot worst than a cheap level meter (they can get very high in price)
Is it better to do it the alternative way on the second link ?
Thanks that is a nice update, Kimmosto must be pleased as he was complaining about it compared to Arta
I forgive you, it was on my first post but it's a long time ago
Dayton Audio EMM-6
-my bad.
If it really bothers you (SPL reference), you can always purchase a UMM-6.
..for freq. response measurements generally - its the easier option.
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-my bad.
If it really bothers you (SPL reference), you can always purchase a UMM-6.
It does not bother me (yet) as long that the data that I will be gathering are accurate enough to allow me to go further in the project without a nasty surprise when doing the crossover
Also I have made an inventory of what tools I need to even start and the list is longer than I expected, so I will try to limit my purchases to the most needed
Completely agree on that difference, if that was my case I would have put the money on some "better" retail products and be done with it, economy of time and maybe even money. But for the hard core audiophiles there do not seem to be a limit on the money they can spend on it.
That's not my thing, what interest me is the process,I want to understand what is required to build a set of speakers with all the do's and don't
I had my hands in car audio a bit years back and spent a long time reading what would make a better sounding installation, finally most of it was making the car more fit for it by making the doors more rigid, increase, mass and eliminate back-wave, find a good place for the drivers location, adjust levels and use time delays, it felt great to end with something decent, I crashed it a few months after and since had company cars that I can't touch.
The home audio have very few elements I can use from my previous experience, it seem like whole another animal to tame, but it is probably because I am going deeper into it.
I am excited but also experience frustration sometimes with my lack of knowledge, tools, space and time that hinder my progress
The help you provide is invaluable and I sincerely am grateful for it, I am going with your proposed design and even I am still puzzled by it I want to see where that will lead me (especially that open-back part)
I would obviously also be satisfied if in the end it sound good to my ears but I don't put my expectation too high for a first project.
Hi Scottg,
Has been some time
Here are the updates on the project :
1- Received the plunging router yesterday (Triton TR001) so I will be able soon to start on working the Test Jig, wanted to make sure to have it before committing on the bits (12mm, 1/2" and 8mm) I will purchase, I am still unsure about the Roundover bit, 12mm tail but the R Value I need to make a 18mm and a 22mm a 90° round isn't clear yet.
2- The AXP-08 arrived also yesterday, at first glance they feel like good quality for the price, ran a test with DATSV2 but ended up with different values than specs, maybe they need some kind of run-in time?
I could only test one driver because the DATSV2 failed for the second (not much luck it seem), even the two calibration tests are failing, have contacted the reseller to a replacement as it is still under warranty.
3- The Fostex FF85WK and a SCR MKP Capacitor, 100µF PA serie (250VDC) to protect the tweeters during tests, but there also I don't have luck because the tracking of the package indicate that it's going back to the reseller, they didn't even came here.
3- I have modified the shape of the driver test rig, please let me know if that is ok, multiplex 18mm for the main part and I plan to use something light for the green parts, I am still trying to figure what exactly, I suppose it has to be somewhat rigid enough for the tests to be ok
Thanks
Has been some time
Here are the updates on the project :
1- Received the plunging router yesterday (Triton TR001) so I will be able soon to start on working the Test Jig, wanted to make sure to have it before committing on the bits (12mm, 1/2" and 8mm) I will purchase, I am still unsure about the Roundover bit, 12mm tail but the R Value I need to make a 18mm and a 22mm a 90° round isn't clear yet.
2- The AXP-08 arrived also yesterday, at first glance they feel like good quality for the price, ran a test with DATSV2 but ended up with different values than specs, maybe they need some kind of run-in time?
I could only test one driver because the DATSV2 failed for the second (not much luck it seem), even the two calibration tests are failing, have contacted the reseller to a replacement as it is still under warranty.
3- The Fostex FF85WK and a SCR MKP Capacitor, 100µF PA serie (250VDC) to protect the tweeters during tests, but there also I don't have luck because the tracking of the package indicate that it's going back to the reseller, they didn't even came here.
3- I have modified the shape of the driver test rig, please let me know if that is ok, multiplex 18mm for the main part and I plan to use something light for the green parts, I am still trying to figure what exactly, I suppose it has to be somewhat rigid enough for the tests to be ok
Thanks
http://www.daytonaudio.com/media/resources/390-806-dayton-audio-dats-quick-start-guide.pdf
Remember that there is a stabilization period for DATS
-hopefully it's not faulty, but IF it is: well it should be in warranty.
Usually test the driver "fresh out of the box" + Rubb and Buzz, and then again after an over-night period with a continuous test-tone around the driver's referenced fs - increase pressure to a point where you can just see the driver's excursion (unless its a high excursion woofer or a really low excursion driver like a small mid.). Usually wire the driver's out-of-phase and place them right next to each other for that break-in period.
http://www.daytonaudio.com/media/resources/390-806-dats-v2-white-paper.pdf
(..I typically just set them on a carpeted floor next to each other without baffle for the break-in period, with a cardboard box over them with several blankets on top of the box.)
Remember that there is a stabilization period for DATS
-hopefully it's not faulty, but IF it is: well it should be in warranty.
Usually test the driver "fresh out of the box" + Rubb and Buzz, and then again after an over-night period with a continuous test-tone around the driver's referenced fs - increase pressure to a point where you can just see the driver's excursion (unless its a high excursion woofer or a really low excursion driver like a small mid.). Usually wire the driver's out-of-phase and place them right next to each other for that break-in period.
http://www.daytonaudio.com/media/resources/390-806-dats-v2-white-paper.pdf
(..I typically just set them on a carpeted floor next to each other without baffle for the break-in period, with a cardboard box over them with several blankets on top of the box.)
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Baffle looks more like an IEC baffle to me. (..I'd personally lower the height of the driver's center on the board slightly, and compensate with height for the stands to get it placed in-room vertically.)
One of the more important aspects though, is the driver's center relative to the room's vertical center: in other words - generally wanting the driver equidistant between floor and ceiling when it's setup properly. So hopefully you've accounted for that.
-btw, I'd probably increase the opening to accommodate 15" drivers..
One of the more important aspects though, is the driver's center relative to the room's vertical center: in other words - generally wanting the driver equidistant between floor and ceiling when it's setup properly. So hopefully you've accounted for that.
-btw, I'd probably increase the opening to accommodate 15" drivers..
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Well just as I was reading your message I remembered one essential thing I forgot about... I played with audio input in the software, and that's the cause of the issue. Have sent a mail right away to reseller to let them know how stupid I feelhttp://www.daytonaudio.com/media/resources/390-806-dayton-audio-dats-quick-start-guide.pdf
Remember that there is a stabilization period for DATS
-hopefully it's not faulty, but IF it is: well it should be in warranty.
Rub & buzz passed for the two
Thanks for the suggestion I will do that during the day next Monday as I am working from home, also the sound travel much to the neighbors, so the night is an issue.
I will have to use my stereo amp to run them together