Hi,
Has anyone worked with the SB17CAC35-8 (or-4) and measured the T&S after few months of use or a strong burning in, please ? Any .frd and .zma known please?
I saw measurments by Audioexcite of the NBAC and the T&S parameters seems to move a lot after burning in vs the datasheet. Would like to know how the CAC version compare in the low end for a small cabinet and if a strong BSC is needed...
Many thanks if any feedback, datas,
Has anyone worked with the SB17CAC35-8 (or-4) and measured the T&S after few months of use or a strong burning in, please ? Any .frd and .zma known please?
I saw measurments by Audioexcite of the NBAC and the T&S parameters seems to move a lot after burning in vs the datasheet. Would like to know how the CAC version compare in the low end for a small cabinet and if a strong BSC is needed...
Many thanks if any feedback, datas,
Model the Fs, Qts and VAS - from both the data sheet and the specs from audioexcite. Tell me if they give you the same enclosure responses (likely within 10%).
The 8 has lower extension than the 4 ohm version if that is important.
The 8 has lower extension than the 4 ohm version if that is important.
Many thanks.
Yes, important as I would work with the -8. and want a small enclosure for a very compact 3 ways where the unit will handle the low it is able to till 650/800 hz. My understanding is there is much more bafle step in the 600 hz area than 800 hz in the surface I want to work with (20 width and up to 40 height)... I have a doubt of the spl at 2.8V the driver can exhibit in the cabinet at the cut-off frequency I plan (ideally 87 db/2.8V for the mid it will work with).
Which datas should I simulate from Goran please, right or left window ? (horizontal or vertical added mass method).
I saw Madisson advised 0.5 cf>3 for a 45 hz f3 which is great but I believe this is from the Vas, Fs & Qts of the datasheet... Am I correct to doubt of such datas after few months of use ?
Yes, important as I would work with the -8. and want a small enclosure for a very compact 3 ways where the unit will handle the low it is able to till 650/800 hz. My understanding is there is much more bafle step in the 600 hz area than 800 hz in the surface I want to work with (20 width and up to 40 height)... I have a doubt of the spl at 2.8V the driver can exhibit in the cabinet at the cut-off frequency I plan (ideally 87 db/2.8V for the mid it will work with).
Which datas should I simulate from Goran please, right or left window ? (horizontal or vertical added mass method).
I saw Madisson advised 0.5 cf>3 for a 45 hz f3 which is great but I believe this is from the Vas, Fs & Qts of the datasheet... Am I correct to doubt of such datas after few months of use ?
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Well I'll eat my own words. I don't know if I would trust the audioexcite horizontal measurement as I take it as the driver lying flat with unknown (?) mass.
The vertical measurement seems more appropriate.
My unbroken in SB17NBAC-4 has an Fs of 38Hz (DATS tested - vertical free air position).
I've got a few sims I'll paste when I can work out how. but you are right the box sizing is quite difference for either sealed or vented based on the audioexcite parameters
The vertical measurement seems more appropriate.
My unbroken in SB17NBAC-4 has an Fs of 38Hz (DATS tested - vertical free air position).
I've got a few sims I'll paste when I can work out how. but you are right the box sizing is quite difference for either sealed or vented based on the audioexcite parameters
Just modeled it with J. Bagbys.
Qts are quite higher than specsheet and it could be easily worked sealed as a mid. However I hope (perhaps naivly cause too much HD below 100hz) to take it as a bass-mid driver with not so big box... so vented. While the EBP and the Qts says both it has a good low end and can be used sealed... but with a much higher -f3 i assume for a driver used for bass as well. that's incredible with a Vab of 14 liters what that driver can do in the lows vented...
If I have a look at HifiCompass, then it is the specs of the datasheet for the T&S.
Qts are quite higher than specsheet and it could be easily worked sealed as a mid. However I hope (perhaps naivly cause too much HD below 100hz) to take it as a bass-mid driver with not so big box... so vented. While the EBP and the Qts says both it has a good low end and can be used sealed... but with a much higher -f3 i assume for a driver used for bass as well. that's incredible with a Vab of 14 liters what that driver can do in the lows vented...
If I have a look at HifiCompass, then it is the specs of the datasheet for the T&S.
I would be careful if I was using data for DATS. DATS 3 will be more accurate from what I understand. The simple reason is DATS is running at extremely low power. Maybe 10mW or something to that effect. Listening to music and bass will probably be about 100 to 1000 times more. The parameter will change. DATS 3 apparently can output a higher power but I haven't tried that yet.
Oon
Oon
A whole bunch of factory frd and ZMA files in here - including your drivers of interest:
Speakers - Google Drive
Speakers - Google Drive
Hi Dave,
Since you have it, I am curious how much power it can output while doing measurements. Could it reach 1W?
From what I understand it has an option of multiple sweeps at different power. Have you tried it. Does it show a lot of change?
Thinking of getting one myself to upgrade from V2.
Oon
/I see nothing in the menus for Dats v3 that allows any level of power / voltage setting. The only thing related to voltage is the scale of display in oscilliscope mode. nothing in the help menu either.
the only option I can think of is somehow looping in an amplifier , being careful to use a voltage divider on the return to the DATS unit to not blow it.
However I've never seen anyone dissatisfied with DATS "low level" sweep accuracy, so unsure whether needed. Driver environment (mounting and surface reflections) and voice coil temperature might have a greater influence than DATS drive level.
the only option I can think of is somehow looping in an amplifier , being careful to use a voltage divider on the return to the DATS unit to not blow it.
However I've never seen anyone dissatisfied with DATS "low level" sweep accuracy, so unsure whether needed. Driver environment (mounting and surface reflections) and voice coil temperature might have a greater influence than DATS drive level.
Hi,
This is from the description from Parts Express.
DATS Linearity Test for comparing parameters and impedance plots at multiple drive levels
Maybe it is under something called Linearity Tests.
Oon
This is from the description from Parts Express.
DATS Linearity Test for comparing parameters and impedance plots at multiple drive levels
Maybe it is under something called Linearity Tests.
Oon
Thanks Celef,
1 V and not 1 W...indonesian style, uh...
Now I am lost....🙁
Well, I will use AudioExcite datas of the sb17NBAC-8 irh vertical measurment and will get off few hz and few Vas. The spl the cac 8 is able to is staying mysterious for me as I am not a math guy.
1 V and not 1 W...indonesian style, uh...
Now I am lost....🙁
Well, I will use AudioExcite datas of the sb17NBAC-8 irh vertical measurment and will get off few hz and few Vas. The spl the cac 8 is able to is staying mysterious for me as I am not a math guy.
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I recall that my DATSv3 used a signal level of about 0.15 V RMS when making impedance sweeps and T/S measurements. This would be considered a "small signal", and it would be safe for any driver including small tweeters with high Fs and low excursion.
Many years ago Morel began quoting two different sets of T/S parameters, one for small signal and one for large signal (which for Morel is 1 V RMS). For example: Morel TiW 638Nd Titanium 6" Woofer, Neo/Ferrite Magnet, 8 ohm
Morel TiW 638Nd Titanium 6" Woofer, Neo/Ferrite Magnet, 8 ohm
So drive level makes a difference, and it is not unexpected, nor is it unique to SBA drivers. However, since SBA has chosen to use 1 V RMS as their standard (according to the post from Celef), it means our DATSv3 results are not directly comparable to published data.
I don't know what the solution is. It would be nice if all manufacturers published T/S data like Morel. It would be nice if DATsV3 had a voltage control feature.
But the real issue is that driver T/S parameters change as the drive level goes up and down. It would be nice if it were constant. It is not. We have to pick some set of T/S values to design our systems with, and there is not a consensus on what that should be. I like 1 V personally. As Dave Bullet says, voice coil temperature will make a big difference, and I suspect the temperature of the spider and surround. So judging which T/S parameter set to use is, well, a judgment. Speaker design is both and art and a science, and judgment calls like this are the "art" part of it...
J
Many years ago Morel began quoting two different sets of T/S parameters, one for small signal and one for large signal (which for Morel is 1 V RMS). For example: Morel TiW 638Nd Titanium 6" Woofer, Neo/Ferrite Magnet, 8 ohm
Morel TiW 638Nd Titanium 6" Woofer, Neo/Ferrite Magnet, 8 ohm
So drive level makes a difference, and it is not unexpected, nor is it unique to SBA drivers. However, since SBA has chosen to use 1 V RMS as their standard (according to the post from Celef), it means our DATSv3 results are not directly comparable to published data.
I don't know what the solution is. It would be nice if all manufacturers published T/S data like Morel. It would be nice if DATsV3 had a voltage control feature.
But the real issue is that driver T/S parameters change as the drive level goes up and down. It would be nice if it were constant. It is not. We have to pick some set of T/S values to design our systems with, and there is not a consensus on what that should be. I like 1 V personally. As Dave Bullet says, voice coil temperature will make a big difference, and I suspect the temperature of the spider and surround. So judging which T/S parameter set to use is, well, a judgment. Speaker design is both and art and a science, and judgment calls like this are the "art" part of it...
J
Attachments
So temperature of the voice coil will drop the spl of 1 or two dbbin the mid ? Even with 85 db average listening level ?
Do you think guys than the CAC 8 ohms can handle 86 db at 2.83 V please at say 700 hz?
Do you think guys than the CAC 8 ohms can handle 86 db at 2.83 V please at say 700 hz?
Re DATS v.3 it can put out up to a maximum stated 11.4dBu (open the oscilloscope & adjust the Z sweep amplitude at the bottom left -it applies to the Impedance Analyser mode also; why they had to bury it there I don't know). 11.4dBu, if my maths is correct, equates to a nominal 2.878v RMS. Standard level is set to 10dBu. Since to the best of my knowledge there is only one way of converting dBu to vRMS, either it's got a higher output than often noted, or some form of unstated 'equivalent' extrapolation is going on. I wouldn't like to say which, I haven't tried physically measuring the output level myself, although out of interest I'll try at some point as I have one on the shelf.
Either way, I've measured a number of the CAC units at 8 & 4ohm persuasions & obtained relatively similar results to Audioexcite etc. in T/S terms with the aluminium cone models. Pair matching is typically good, Fs usually within target production tolerance, Q usually higher, Vas lower than published. I'm not in a position to upload the data as it was not done in a DIY context; however, I'm impressed with the quality of the CAC drivers.
T/S data is not fixed -it varies a little, even after break in with VC and ambient temperature, so expect some differences in the same drive units measured on different days or in slightly different conditions.
Either way, I've measured a number of the CAC units at 8 & 4ohm persuasions & obtained relatively similar results to Audioexcite etc. in T/S terms with the aluminium cone models. Pair matching is typically good, Fs usually within target production tolerance, Q usually higher, Vas lower than published. I'm not in a position to upload the data as it was not done in a DIY context; however, I'm impressed with the quality of the CAC drivers.
T/S data is not fixed -it varies a little, even after break in with VC and ambient temperature, so expect some differences in the same drive units measured on different days or in slightly different conditions.
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