Measuring T/S parametrs

[sva86]

Hello!
This is my first thread in the forum,and i like to thank everyone for crating this wonderful community.
I`m trying to measure a speaker t/s parameters for a firs time.I have the knowledge and equipment,but
have confused about some of the results.Most of the data is looking good to me,but two measurements differ too much from the manufacturer data.
The Fs (free air resonance frequency) and the VAS.
The manufacturer Fs is : 42hz but the measured one is 53Hz.
The vas have to be between 24-34l but the measured is 18.8l.
I have checked all the signal parameters with oscilloscope and and frequency counter,there was no
objects around the tested speaker to affect the measurement,and that is why i`m confused!
The only thing that is the speaker i tested have not "braked in"(Burned in).
Can this affect the measured data so much,were can i be mistaking?
Or the Manufacturer lie about the data?

If some one with more experience had this issue?

Regards.

 

[TLS Guy]

Hello!
This is my first thread in the forum,and i like to thank everyone for crating this wonderful community.
I`m trying to measure a speaker t/s parameters for a firs time.I have the knowledge and equipment,but
have confused about some of the results.Most of the data is looking good to me,but two measurements differ too much from the manufacturer data.
The Fs (free air resonance frequency) and the VAS.
The manufacturer Fs is : 42hz but the measured one is 53Hz.
The vas have to be between 24-34l but the measured is 18.8l.
I have checked all the signal parameters with oscilloscope and and frequency counter,there was no
objects around the tested speaker to affect the measurement,and that is why i`m confused!
The only thing that is the speaker i tested have not "braked in"(Burned in).
Can this affect the measured data so much,were can i be mistaking?
Or the Manufacturer lie about the data?

If some one with more experience had this issue?

Regards.

A lot of manufacturers have huge driver to driver variation. What you are getting is par for the course. Believe your data and not the manufacturers.

What is the make a model of the driver? Far Eastern drivers are so often all over the place. If you spec. drivers form a company like SEAS then one driver is much more likely to be like the next. Consistency in manufacture is one of the things you have to be prepared to pay for.

If you are going to build your own speakers, spec quality drivers. Your hard work is worth it.

 

[sva86]

Thanks for the quick reply.
Yes i want to build my own speakers.
The driver is Peerless SKO- 165 WTR(POLY) for which i have the data,but only for
the 8ohm version and i have the 4ohm one.The t/s differ between them for sure.
But Fs is the same,and the VAS of the lower impedance has to be smaller but 18l is too
lower than 34l of the 8ohm one.

 

[TLS Guy]

Thanks for the quick reply.
Yes i want to build my own speakers.
The driver is Peerless SKO- 165 WTR(POLY) for which i have the data,but only for
the 8ohm version and i have the 4ohm one.The t/s differ between them for sure.
But Fs is the same,and the VAS of the lower impedance has to be smaller but 18l is too
lower than 34l of the 8ohm one.

Do you have a link to that driver? I can't find it anywhere, not even on the Tymphany site. If it is a discontinued driver then do not use for a new build. You only ever spec an older driver, is it is so good and famous, there is a plentiful supply on the used market.

I can't find that driver at all, so if your part No. is correct pick another driver. If that is a driver from the Peerless Indian division you are definitely down the wrong alley.

 

[sva86]

Yes it is discontinued driver.That is why i don't have any info on it!
And Yes i think it is from the Indian division.
This is the only thing written on them.
https://i.ebayimg.com/images/g/sv0AAOSwfIxZaJNx/s-l1600.jpg
https://cdn.shopify.com/s/files/1/0809/2387/products/Dave00656.jpg?v=1494342190
I think that this driver was used in the KEF Coda 8 but not sure.

 

[TLS Guy]

Yes it is discontinued driver.That is why i don't have any info on it!
And Yes i think it is from the Indian division.
This is the only thing written on them.
https://i.ebayimg.com/images/g/sv0AAOSwfIxZaJNx/s-l1600.jpg
https://cdn.shopify.com/s/files/1/0809/2387/products/Dave00656.jpg?v=1494342190
I think that this driver was used in the KEF Coda 8 but not sure.

Don't waste your time building speakers with those drivers. Pick something else.