TS Parameters & FR Curves Of Driver Batches.

[acoustics]

hi all diyer's
i need to share some information with all of you diyer's out there. This is regarding the TS parameters of the drivers we use in our builts. Sometime back i bought a center speaker kit from Mr. Sumit Khanna in New Delhi and i posted a thread regarding this wonderfull kit. Now i was supplied the enclosure dimensions as well as the TS parameters for both the peerless M13NH midbass and the tweeter used in this kit but because the enclosure dimensions were there so i simply got the speaker built using those and never bothered to look at the TS parameters of the peerless M13NH mid
This is the thread i posted related to this thread

http://www.hifivision.com/diy/21040-diy-center-channel-kit-based-m130-midbass.html

two days back i thought of making a surround speaker pair so i picked up the TS parameters of m13nh which were supplied to me with the center channel kit and when i saw the FR curve i was surprized that this was different and smoother than the FR posted on the peerless website for this driver
this is the FR curve i was given for my kit



and this is what's posted on peerless website for M13NH



from the images it can be seen that both the drivers being the same have different FR curves as well as different parameters

so i contacted Mr. sumit and on this issue and he told me that we get the FR curves for each lot of drivers and these are sometimes different so we design our kits as per the TS parameters supplied with each lot because sometimes there is a lot of variation and i was happy and thankfull to him that i got the versions of M13NH which are similar in response to the GR version of this driver

this is not all , now i have a friend who also experiments with speakers and i got a third version of FR curves and TS parameters for M13NH from him

this is it



the region marked in the red shows that this version of M13NH doesnt have a smooth upper end as on the other versions

hyeah:

and when you check the peerless website archieve through the wayback machine you will find a fourth set of TS parameters and FR curve :yahoo:

so what do we learn

dont just buy the drivers without just from anyone and without the authentic
FR and TS parameters
because there are a lot of us who dont have the means to measure the actual driver data and we just have to rely upon the data supplied so its very necessary to be sure about the data that you tend to use along with the drivers to be correct

Now the question is how do we make sure that we have the correct data

either measure your drivers if you have the means or
pick up your drivers and check the magnet , each peerless driver has a set of stickers on the magnet take down the numbers on these one of these marks the lot ID and contact peerless they can send you the TS parameters for that lot

Thanx for reading this hope this helps some of you hyeah:

 

[doors666]

re: TS Parameters & FR Curves Of Driver Batches.

even for established manufacturer's like scanspeak, seas, vifa etc, the published t/s parameters are different from whats measured by people after purchasing the drivers. i would rather trust third party measurements rather than the manufacturer. now if consistency between batches varies a lot, that indicates qc issues.in that case, you need to measure urself and choose closely matching drivers.

 

[acoustics]

re: TS Parameters & FR Curves Of Driver Batches.

I agree that the parameters measured by people are different to what are supplied by companies, but it should be remembered that the companies use very expensive and accurate measurement systems. The curves posted above are all provided by peerless and the measurements are done by the same system. This moreover looks like a lot to lot variation and a qc issue. So better measure before using.

 

[anilva]

re: TS Parameters & FR Curves Of Driver Batches.

hi all diyer's
i need to share some information with all of you diyer's out there. This is regarding the TS parameters of the drivers we use in our builts. Sometime back i bought a center speaker kit from Mr. Sumit Khanna in New Delhi and i posted a thread regarding this wonderfull kit. Now i was supplied the enclosure dimensions as well as the TS parameters for both the peerless M13NH midbass and the tweeter used in this kit but because the enclosure dimensions were there so i simply got the speaker built using those and never bothered to look at the TS parameters of the peerless M13NH mid
This is the thread i posted related to this thread

http://www.hifivision.com/diy/21040-diy-center-channel-kit-based-m130-midbass.html

two days back i thought of making a surround speaker pair so i picked up the TS parameters of m13nh which were supplied to me with the center channel kit and when i saw the FR curve i was surprized that this was different and smoother than the FR posted on the peerless website for this driver
this is the FR curve i was given for my kit

View attachment 6136

and this is what's posted on peerless website for M13NH

View attachment 6137

from the images it can be seen that both the drivers being the same have different FR curves as well as different parameters

so i contacted Mr. sumit and on this issue and he told me that we get the FR curves for each lot of drivers and these are sometimes different so we design our kits as per the TS parameters supplied with each lot because sometimes there is a lot of variation and i was happy and thankfull to him that i got the versions of M13NH which are similar in response to the GR version of this driver

this is not all , now i have a friend who also experiments with speakers and i got a third version of FR curves and TS parameters for M13NH from him

this is it

View attachment 6138

the region marked in the red shows that this version of M13NH doesnt have a smooth upper end as on the other versions

hyeah:

and when you check the peerless website archieve through the wayback machine you will find a fourth set of TS parameters and FR curve :yahoo:

so what do we learn

dont just buy the drivers without just from anyone and without the authentic
FR and TS parameters
because there are a lot of us who dont have the means to measure the actual driver data and we just have to rely upon the data supplied so its very necessary to be sure about the data that you tend to use along with the drivers to be correct

Now the question is how do we make sure that we have the correct data

either measure your drivers if you have the means or
pick up your drivers and check the magnet , each peerless driver has a set of stickers on the magnet take down the numbers on these one of these marks the lot ID and contact peerless they can send you the TS parameters for that lot

Thanx for reading this hope this helps some of you hyeah:

You could have named your subject line better instead of making it look sensational...this is not done.

 

[t.antony]

re: TS Parameters & FR Curves Of Driver Batches.

Across the 3 graphs, there is uniformity in the operating frequency region of the driver, and it's interesting to see that the critical lower mid bass region is virtually same.

Peerless India drivers said to have mid range quality closer to the scan-speaks, and it showed in my measurements also. http://www.hifivision.com/diy/16612-my-mtm-stand-mount-loudspeakers-9.html#post279432.

I have measured drivers from 2 lots and found the Peerless data to be fairly accurate and the tolerance levels between individual drivers within workable range. May be the QC is not way off compared to their export quality .

BTW the last graph seems to be taken from a lot supplied to Varsha Electronics.

 

[acoustics]

re: TS Parameters & FR Curves Of Driver Batches.

Hi Antony you are right the sq from these drivers is awesome , and yes the last graph is from varsha electronics, there is a big drop just after the 1 kHz mark and this doesn't look good

 

[t.antony]

re: TS Parameters & FR Curves Of Driver Batches.

Hi Antony you are right the sq from these drivers is awesome , and yes the last graph is from varsha electronics, there is a big drop just after the 1 kHz mark and this doesn't look good

The drop is occurring after 10Khz, not 1kHz. It does not affect the sound quality as these drivers are usually crossed around 2500Hz.

 

[acoustics]

re: TS Parameters & FR Curves Of Driver Batches.

yes you are right on this antony its 10 k and not 1k , i misread it because the scanned copy i got in my email is not that clear and is very small , so this version of m13 also seems good but anyways the TS parameters differ so i think before using these plz check the parameters