Are these drivers defective?

[system7]

Yes, the bottom end below 40Hz is of little interest in most measurements but it was preventing me from calculating the T/S parameters. Now, that's a bit of a show-stopper for speaker design, isn't it? [emoji2]

You can measure stuff yourself, or just go to the published speaker specs. I'd generally expect the manufacturer to know more than you do about Thiele-Small bass performance.

I notice you are being very secretive about the exact woofer. It seems to have a fairly high basic Fs resonance. Around 70Hz. It might be a parcel-shelf car woofer for all I know.

You take your beating on enclosures. Generally high efficiency equates to big enclosures and stiff surrounds and a lack of low frequency performance. I'd trust a picture of a woofer more than anything to know what to do with it.

 

[tcpip]

You can measure stuff yourself, or just go to the published speaker specs. I'd generally expect the manufacturer to know more than you do about Thiele-Small bass performance.

Not correct. You can only depend on some manufacturers to publish accurate figures, and maintain manufacturing QC tight enough to retain consistency of parameters over the years. The woofer I'm working with is quite the opposite. I took up a project to design a couple of inexpensive speakers with Indian drivers, and those drivers don't have trustworthy published data. In fact, I bought a tweeter from the same manufacturer with published Fs of 596Hz, and I'm getting measured Fs clearly around 1KHz. Read all about the whole scoop here. I'd measure every Tang Band or HiVi driver I use, if I ever use them.

I notice you are being very secretive about the exact woofer.

This is a funny comment. You never asked. I am using the Peerless India SM16IH-4. The only reason I never mentioned the model specifics was because diyaudio.com is an international community and no one here will know or care about a small Indian brand of mediocre speaker drivers.

It seems to have a fairly high basic Fs resonance. Around 70Hz.

No, it's about 55Hz. (A few posts back, I'd posted graphs of two drivers, a 5.25" with an Fs of about 63Hz, and a 6.5" with an Fs of about 55Hz. Please ignore the 5.25" graph.) I agree that 39Hz would have been nicer, though.

 

[tcpip]

If anyone is interested in Peerless India drivers and their story, check this post from Feb 2004 and this page written in 2010. No secrets here.

When these things were written, these Peerless India options were the only game in (the Indian DIY) town. Now, with easing of imports into India and international transactions becoming routine, more DIYers are able to order directly from Parts Express and Madisound.