mini dsp hears show always too much in spl meter and can not calibrate

[user44455555]

Hello

I have done a testfile which contain no sensivity data and i want calibrate but REW do not allow calibrate. I have a ambient noise db(A) in my room of around 35 db. the hears have dip switches. in the default (18 db set in hears) rew spl meter show around 57 db(A). when i switch to 0 db setting rew show around 40 db. so i need reduce 5 db more that spl is show correct in rew . rew control input volume setting do nothing change in spl meter output. How i can calibrate that it show correct values ?

I want use hears for speaker room correction too because the ear shape filter room reflections as real ears do and i get much better sound results now what i hear and in compare to headphone. and btw this explain wy target curves with reduce heights are used. with omni microphone there see only 2 large room modes at 88 hz and 160 hz. so everybody assume reduce this nodes by around 8 db and you get a good linear sound. but thats wrong. the minidsp hears show the true. the mids need boost . I need not reduce the room modes a EQ 700 hz q 0.5 3 db and i get amazing sound very simular to headphone. also the gap at 5.3 khz that hears show is true. because it sound even more simular when i boost this with Q 4 2.5 db

 

[user44455555]

does rew support the phase value of correction file ? . is this important phase shift ?

the correction file l(can download for my serial number) contain this. I delete sens factor in my test file.

"Sens Factor =0.9dB, EARS Serial xxx-xxxx, compensation HPN V1"
"Use this file on the RIGHT channel. Your sensitive side is RIGHT."
*
* HPN: Default headphone compensation curve for miniDSP EARS
*
* For use with headphones. Do not use with IEMs.
*
* Changelog:
* Version 1, 12 Dec 2017 : Initial version
*
* Freq(Hz) SPL(dB) Phase(degrees)
*
10.0 -2.1 3.8
10.6 -2.0 3.7
11.2 -2.0 3.5
11.8 -1.9 3.4
12.5 -1.9 3.2
13.2 -1.8 3.1
14.0 -1.7 2.9
15.0 -1.5 2.7
16.0 -1.3 2.5
17.0 -0.9 2.3
18.0 -0.5 2.3
19.0 -0.2 2.2
20.0 0.0 2.2
21.2 0.2 2.1
22.4 0.3 2.1
23.6 0.3 2.1
25.0 0.4 2.0
26.5 0.4 2.0
28.0 0.5 2.1
30.0 0.7 2.2
31.5 0.8 2.2
33.5 0.9 2.2
35.5 1.0 2.1
37.5 1.0 2.2
40.0 1.1 2.3
42.5 1.2 2.4
45.0 1.2 2.5
47.5 1.2 2.5
50.0 1.3 2.6
53.0 1.3 2.7
56.0 1.3 2.8
60.0 1.3 3.0
63.0 1.2 3.0
67.0 1.2 3.2
71.0 1.2 3.3
75.0 1.2 3.5
80.0 1.2 3.6
85.0 1.1 3.8
90.0 1.1 4.0
95.0 1.1 4.2
100.0 1.0 4.4
106.0 1.0 4.6
112.0 1.0 4.8
118.0 0.9 5.1
125.0 0.9 5.3
132.0 0.9 5.6
140.0 0.9 5.9
150.0 0.9 6.3
160.0 0.9 6.6
170.0 0.9 7.0
180.0 0.9 7.4
190.0 1.0 7.7
200.0 1.0 8.1
212.0 1.0 8.5
224.0 1.0 8.9
236.0 0.9 9.4
250.0 0.8 9.9
265.0 0.8 10.4
280.0 0.7 10.9
300.0 0.6 11.7
315.0 0.6 12.2
335.0 0.5 12.9
355.0 0.4 13.6
375.0 0.2 14.2
400.0 0.2 15.1
425.0 0.1 16.0
450.0 0.0 16.9
475.0 -0.1 17.7
500.0 -0.2 18.6
530.0 -0.2 19.6
560.0 -0.3 20.6
600.0 -0.3 22.1
630.0 -0.4 23.0
670.0 -0.4 24.4
710.0 -0.3 25.8
750.0 -0.3 27.0
800.0 -0.2 28.7
850.0 -0.1 30.5
900.0 -0.1 32.3
950.0 0.0 33.9
1000.0 0.0 35.6
1060.0 0.0 37.6
1120.0 0.1 39.7
1180.0 0.2 41.7
1250.0 0.2 44.2
1320.0 0.3 46.7
1400.0 0.4 49.3
1500.0 0.6 52.3
1600.0 0.9 55.4
1700.0 1.2 58.3
1800.0 1.5 60.8
1900.0 1.8 62.9
2000.0 2.1 65.1
2120.0 2.4 68.0
2240.0 2.7 71.6
2360.0 3.1 75.7
2500.0 3.6 81.2
2650.0 4.3 87.8
2800.0 5.3 95.1
3000.0 7.3 103.6
3150.0 9.3 108.9
3350.0 12.5 110.3
3550.0 15.9 104.0
3750.0 18.8 91.9
4000.0 21.2 67.5
4250.0 22.3 37.9
4500.0 21.2 7.4
4750.0 18.3 -8.2
5000.0 16.4 -12.1
5300.0 15.6 -17.5
5600.0 14.0 -33.6
6000.0 9.9 -43.1
6300.0 7.2 -39.4
6700.0 5.1 -30.4
7100.0 3.9 -22.5
7500.0 3.1 -16.5
8000.0 2.5 -10.1
8500.0 2.3 -5.4
9000.0 2.1 -2.4
9500.0 2.0 -0.8
10000.0 1.9 0.1
10600.0 1.8 0.5
11200.0 1.5 0.4
11800.0 1.0 0.2
12500.0 0.5 0.0
13200.0 -0.2 -0.1
14000.0 -1.1 0.1
15000.0 -2.1 0.3
16000.0 -3.0 0.7
17000.0 -3.9 1.0
18000.0 -4.7 1.0
19000.0 -5.1 0.9
20000.0 -5.6 0.6

the text sens factor i remove in my testfile but REW allow me not to calibrate

 

[John Mulcahy]

To manually calibrate when there is no sens factor figure in the USB mic's cal file just say No when REW asks if you have a cal file. It won't remove the file you have already loaded, it is just asking as a way to get a sensitivity value. Alternatively put the sens factor line back in the cal file you made and adjust the figure for the change in gain. Phase data in cal files is used if it is present.

 

[user44455555]

thanks, I find other thing that cause the problem. it is control input volume setting In java audio. when i choose the hears rew select automatic 0,53 . when i switch to my analog microphone input the values stay on 0.53 . but my analog microphone have 0.71. So this value is not store for every sound device. when i disable control input volume in my analog input, then when choose hears input and later analog input it enable automatic for analog input and value 0.53

 

[John Mulcahy]

I'll change the code so control of input volume stays disabled if you select that.

 

[user44455555]

I am not the only with the problem. I have put the rta with the hears and with my soundlevel meter calibratet microphone in a post to thos thread. at 1 khz the hears show 20 db too much spl. so seem i need change sens factor to 21 db. https://www.minidsp.com/forum/ears-...l-levels-way-off-after-following-manual#61126

 

[John Mulcahy]

The sens factor should change by the same amount as the gain, but the cal file shape will also affect the SPL figure because the cal file corrections are applied before calculating the SPL. If the cal file has a different response the sens factor may no longer be appropriate for that new response for a broadband signal, though it may still be correct at 1 kHz (assuming the cal files are zero there) which is the frequency used by most calibrators.

 

[user44455555]

thats really strange how this hears can change the gain setting with dip switches (between 0 db and 36 db. it work really because it can see that dbfs value when have ambient noise change. after such a change and restart of REW spl show near same too high SPL value between 0 and 18 db. the write in their manual that no calibration file need change. sens factor of my files are 0.9 db.

how it is possible that REW show same spl when reloiad the cal file after a gain change ?. does the USB driver of this device report some sens information ?

2
Switches 1 to 3 control the internal gain of the microphone amplifier, as shown in Table 1. (Switch 4 is not used.)
The default gain as shipped and as indicated in the diagram above is 18 dB.

.6.5 Measuring at higher SPLs
If you measure headphones at a reference SPL higher than 84 dB, or IEMs at a reference SPL higher than 94 dB,
you may find that the measurement signal clips. In that case:
1. Quit REW.
2. Unplug the USB cable from the EARS.
3. Reduce the analog gain of the EARS using the DIP switches (see page 7).
4. Connect the EARS to the computer by USB.
5. Start REW and re-select the calibration files.
Note: you do not need to edit your calibration files.

 

[John Mulcahy]

The cal file response data will not need to change, but the sens factor will.

 

[user44455555]

As far i understand the sens factor is only in the cal file so i need edit it. but they write in manual

Note: you do not need to edit your calibration files.

in https://www.minidsp.com/images/documents/EARS User Manual.pdf page 17 stand that the preamp level can change and after a reload of the same cal file the calibration should be correct they write. that this can work there need on other place a sens factor. maybe in usb device ?