T/S Parameter Sanity Check - Sub Measurements

[Seriosha]

Hey Guys, last Weekend is was finally able to put my DATS V3 to work. Unfortunately, the way to get there was rough, to say it nicely. After my diy-testbox was too big according to the DATS - 47liters, and not rethinking that error even after reducing the volume by almost 10liters, i threw the box in the garbage and did weight based Vas measurements. The two subs have both seen service in a dual ~30l (for each) sealed box in car-audio, were then put in the basement for quite some years, and were now pulled out to give them a new life.

Here are my measurements along with the manufacturer ones. It seems weird to me that they are that far apart from each other.

Since i want to built separate Enclosures for them,would a recommendation for one of those change in respect of the measurements?

Intended use is Home-Theater and Music at Home.

Thanks for your knowledge =)

 

[hagenfeuchter]

Hey Guys, last Weekend is was finally able to put my DATS V3 to work. Unfortunately, the way to get there was rough, to say it nicely. After my diy-testbox was too big according to the DATS - 47liters, and not rethinking that error even after reducing the volume by almost 10liters, i threw the box in the garbage and did weight based Vas measurements. The two subs have both seen service in a dual ~30l (for each) sealed box in car-audio, were then put in the basement for quite some years, and were now pulled out to give them a new life.

Here are my measurements along with the manufacturer ones. It seems weird to me that they are that far apart from each other.

Since i want to built separate Enclosures for them,would a recommendation for one of those change in respect of the measurements?

Intended use is Home-Theater and Music at Home.

Thanks for your knowledge =)

It is not uncommon for machine made drivers (most on the market). to have variance. Best optimize design for the actual woofer.. do not worry about the mfg specs... long as your measurements are good. Other thin to consider is the room effect for

 

[hagenfeuchter]

It is not uncommon for machine made drivers (most on the market). to have variance. Best optimize design for the actual woofer.. do not worry about the mfg specs... long as your measurements are good. Other thin to consider is the room effect for

subs is much greater than the design difference you might have with the 2 subs

 

[wus]

SWR-1221D are from Alpine, right? They seems to have Santoprene (rubber) surrounds. They might have changed their properties due to the long inactive storage. If the surrounds still look o.k., it might help to drive them with low frequency (15 to 20Hz) to reasonably high excursion - maybe +/- 5mm - for 24 hours (open air, so be careful when turning up the volume - it is easy to damage speakers in this condition with surprisingly low power).

Repeat the TSP measurement again afterwards.

 

[Dourou]

Hi,
I had a similar problem with my main speakers’ 8’ woofers. Went on to change the rubber and the sound (and response and sensitivity) changed by leaps and bounds.
Mine felt quite stiff to the touch btw.

 

[Seriosha]

Hey =)

Yes, those are Alpines.
I wired them to an Amp before Measuring them and played variating Sine Tones for about 10 minutes with visible excursion before i measured them to get rid of the usual stiffness after non-use. Not a 24h Stint tho ^^ I don't know about the sourround material, only that the diaphragm is Kevlar reinforced Pulp and the Spider is Nomex.

I put them both in WinISD and get pretty different results, one for a 23 Hz tuned 110 Vented Enclosure, and the other for a 27Hz Tuned 65lVented Enclosure - i will built the 65lVersion in the next days and see how it works. And i guess i will also put the other sub in there just for comparison too