GTI series,car woofers. what Pro or home drivers are the smaller drivers based on?

[1audiohack]

I now have the pair pictured in post #15. I have not measured them in any way yet. I stacked together a slightly larger bedroom system and just dropped the GTI1000's in a pair of .7ft3 sealed boxes with one pound of fiberglass until I get around to building some that fit in the bookcase and they sound surprisingly good just like that.

I have never seen a pro or consumer counterpart of this speaker, that surely doesn't mean there isn't though.

I'm not using them above 100 Hz but if there was something I could measure that would help you out let me know.

[pos]

Thanks! That would be very helpful if you could measure the top end behavior, so my friend can adjust the low pass section of the econowave network knowing what he is doing (he does not have any measurement tool or knowledge, and live ~700km from here).

Did you change the dustcap, or just painted it black?

[1audiohack]

The top line on both graphs is mic on axis, the lower line is 45° off axis. In case the small print is hard to read the top graph is frequency response the lower is phase, all from one sweep with two mic's@ 1meter. The data is rock solid down to 200Hz and believable to 100 Hz, no smoothing applied.

If this isnt what you're after let me know. I don't have my scope or Fluke at the house so I can't give you drive voltage, I will get it if you need it.

The dust caps were on them when I get them.

All the best,
Barry.

[Eaulive]

The top line on both graphs is mic on axis, the lower line is 45° off axis. In case the small print is hard to read the top graph is frequency response the lower is phase, all from one sweep with two mic's@ 1meter. The data is rock solid down to 200Hz and believable to 100 Hz, no smoothing applied.

If this isnt what you're after let me know. I don't have my scope or Fluke at the house so I can't give you drive voltage, I will get it if you need it.

The dust caps were on them when I get them.

All the best,
Barry.

What's the purpose of having two microphones? Better averaging of dips and peaks? No need for smoothing?

Interesting curves you have, I never get them so clean unless I apply smoothing
Of course my environment is always less than ideal.

[1audiohack]

My measuring environment today is my driveway between rains. We love rain!!!

I swept this at 2000 Hz/second with a 20 Hz wide filter, not much time to include noise. Anechoic by definition to 150 Hz.

The mic off axis is for indicating directivity.

[pos]

Thanks a lot Barry!!

That broad 5dB peak at 650Hz will have do be delt with in the passive crossover, as the crossover point will probably be around 1200Hz
How large is the baffle (to assert the baffle step) ?

Thanks again, that is very helpful

[1audiohack]

Hi Thomas;

The baffle on this test box is almost nonexistent at only 10 high and 11 inches wide. It was measured 2M above ground in free space. If something else would be helpful please let me know.

All the best,
Barry.

[mtchyz250f]

What is the top end extension of the 1500Gti, 100, 200, 400hz?

[grumpy]

the spec sheet claims a frequency response of 20Hz-300Hz ...
likely insufficient information to be of much use,
but it matches up with dimensionality of the question.

http://www.jbl.com/resources/Brands/...rs/1500GTI.pdf

[mtchyz250f]

Thanks grumpy. But I find those to be very optimistic in most cases. Specifically do you think in can be used to 200Hz?

[grumpy]

Keeping in mind that the impedance drops quite low,
-if- you're actively crossing over and the amp is up to it,
then sure... 200Hz would probably still work OK.

If what you're intending to cross them over to can handle
lower frequencies, it would be worth trying.

Keep in mind the the driver was designed as a subwoofer,
not a mid-bass driver.

[mtchyz250f]

Thanks again grumpy. I appreciate your patience with me. Let me get into the application a little more to save some time. I have a friend who teaches music part time and wants a simple and inexpensive system for critical listening. He has an old SoundStream Rubicon 5ch amp with built in 12 db active crossovers.

My thinking was with the GTI he would get great sensitivity needed for the low power amp and be able to cross to the OEM door speakers a little higher so as not fry them when he turns the volume up a little; while still getting great sound. Later he can upgrade the door speakers to something a little better. Do you think the GTI is the right speaker, is my thinking correct?

Thanks again for your time.

[grumpy]

one of the 5ch amps with a dedicated sub channel (more power on the sub amp)?

If you want efficiency, go for the vented example in the pdf, I prefer the sealed
sound, but it takes more power to drive it (up to 10x at 50Hz)... and I'm not a
"boomer"

I'd still recommend going lower in the crossover frequency if you can... the JBL
box examples are using 70Hz for a smooth-ish blend and crossover. So somewhere
between there and 100Hz is what I would be trying. You'll also likely need to adjust
the levels between the sub channel and the others... hopefully there are controls
on the amp for that.

All that said, the GTI sub is massive overkill for pairing up with a set of stock
in-door drivers, but that shouldn't stop you from having some fun.

Cheers.

[mtchyz250f]

Thanks grumpy, that is everything I needed to know.

[Lee in Montreal]

BTW I have a 1800GTi and found that anything above 100Hz was pretty muddy. It'll be used as a 2 octave driver. 20-80Hz.