Radial(Tangerine) versus the regular circumcerential phase plug

[Baaronj]

Have you made sure the phase-plug ( from the the lower level driver > which I believe is the tangerine one ) is still glued in properly?

That glue does eventually let go ( that's much more likely a problem than a magnetic polarity problem ).

I have not check on the Tangerine's glue, but I have changed the 'phragms out several times and didn't notice anything amiss.

I took some quick measurements with my iPhone RTA app this morning...I did these from right on top of the horns - I realized afterward I probably should have done them from 1-3 feet out. Still, it's pretty much what I thought I was hearing. The question is, how much of this is due to the phase plugs vs. other stuff?

If it's all due to the phase plugs, it looks like a pretty compelling case for the superiority of the radial/Tangerine types...these measurements were taken on pink noise with the Markwart L-pads set to the middle (12 o'clock)....

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I just spoke to Bill at GPA. He said he could replace the circumferential phase plug with a Tangerine. I'm going to do take more measurements - and swap the diaphragms out - before I go to the trouble of sending the speaker to GPA.

[Earl K]

I have not check on the Tangerine's glue, but I have changed the 'phragms out several times and didn't notice anything amiss.

I took some quick measurements with my iPhone RTA app this morning...I did these from right on top of the horns - I realized afterward I probably should have done them from 1-3 feet out. Still, it's pretty much what I thought I was hearing. The question is, how much of this is due to the phase plugs vs. other stuff?

If it's all due to the phase plugs, it looks like a pretty compelling case for the superiority of the radial/Tangerine types...these measurements were taken on pink noise with the Markwart L-pads set to the middle (12 o'clock)....

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I just spoke to Bill at GPA. He said he could replace the circumferential phase plug with a Tangerine. I'm going to do take more measurements - and swap the diaphragms out - before I go to the trouble of sending the speaker to GPA.

Thanks for the pics ( #2 is certainly the best IMO ).

Testing right in front of the horn is just fine for this type of trouble-shooting exercise ( IME ).

EarlK

[Baaronj]

Thanks for the pics ( #2 is certainly the best IMO ).

Testing right in front of the horn is just fine for this type of trouble-shooting exercise ( IME ).

EarlK

I agree. I'm going to do some more testing and will report back if I find anything of note.

[GM]

I always assumed that the primary reason that my model 19's have a significantly/noticeably "better" extended high frequency response than my Valencias is because of the radial phase plug design incorporated into the 802 driver compared to the circumferential design used with the 806 (Valencia) driver (the 19's seem to have a flatter h.f. response than the Valencias--they don't start to drop off at 13k).

I'm not argumentative by nature so please don't take this the wrong way but it seems like either you two guys are underestimating the effect of the "improved" phase plug design or I'm over-estimating it and Altec was over "hyping" it?

As already noted, there's a major difference beyond phase plugs that explains the HF performance difference, so what needs to be tested is a comparison of an 808-8A, 802-8G in M19s or any speaker using the M19's 811, XO and pretty sure there will be little, if any, difference since with such a high XO point the 802-8A's phase plug won't be so resistive nor will the horn's inertance be so high, hence less HF roll off up high.

GM

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GM...You state that the band width shifted on the 802 with the tangerine driver on a 511. What are your thoughts on the 288 with the circumferential phase plug vs the tangerine. Does something similar happen with a large format driver such as the 311-90? Thanks.

The 802-8G was a whole new design, not just a different phase plug, i.e. gave up a little LF for more extended HF. I've no experience with any Altec large format driver other than the early 288, but again it in theory would only do if the new 288s are redesigned to do similar. Is there any measurements posted somewhere? I couldn't find any.

GM

[mah]

FWIW.

http://alteclansingunofficial.nlenet...ers/TL_231.pdf