Why do my 288-8Ks sound like cr@p?

[Coendert2011]

Coen, the 12kHz bump is what you get with the 288's - that's normal. The bump goes away off-axis, so the power response is usually quite smooth. I think that the response of your realigned 288's is very acceptable. I suspect that GPA diaphragms won't bring anything much better.

Hi Vuki, maybe I was a little overconfident that the new diaphragms would cure the harshness and a little too fast in ordering for shure. Well they are paid for and on the road so let's wait and see for the final verdict.
Anyhow, even if these do not make the desired difference I really would like to proceed to get to the bottom of this and make them sing in my setup. Your off axis graph for instance makes a lot if sense to me.

I noticed the 12k bump in the other 288-k graphs before. Save for what the diaphragms may bring this is suspect nr 1 next on the list. Furthermore I'm interested in your opinion on the 288-8k, do you like them all theway up, or do you consider a seperate (super) tweeter like gm suggested?

Coen

[vuki]

I'm using them without supertweeter. They sound (to my ears) better than 902s on 511 or even tractrix. BTW those were GPA dias in the 288k's that were measured.
I suggest you to measure 902 on 511 with the crossover than the 288, keeping the exactly same measuring conditions (distance, mic placement, amp gain etc). Using ARTA's overlay function you'll probably find out more about sound difference between those drivers.

[Altec Best]

Hi Vuki, maybe I was a little overconfident that the new diaphragms would cure the harshness and a little too fast in ordering for shure. Well they are paid for and on the road so let's wait and see for the final verdict.

Good Point ! There is nothing wrong with having a pair of new diaphragms. They are the weak point in the driver and fatigue...

[Earl K]

Hello Coen,

Well, more than 4 months have passed , so;

I'm wondering if you have any updates to share with us about your 288/511E setup ?

Did you receive those GPA diaphragms ( # 23763 ?? ) that you ordered & did you load them up & measure their performance ( etc. ) ?

Did you go back to listening to the 802/511 as your primary setup ? ( if so , why ? / if you don't mind me asking )



cheers <> EarlK

[Coendert2011]

Hello Coen,

Well, more than 4 months have passed , so;

I'm wondering if you have any updates to share with us about your 288/511E setup ?

Did you receive those GPA diaphragms ( # 23763 ?? ) that you ordered & did you load them up & measure their performance ( etc. ) ?

Did you go back to listening to the 802/511 as your primary setup ? ( if so , why ? / if you don't mind me asking )



cheers <> EarlK

Hi Earl,

Thanks for the interest.
I have been very busy with my family during the summertime and left this project for rainy autumn and winter nights!

Being so busy I did not pay enough attention to an important lack. As a matter of fact I never received the GPA replacement diaphragms.
Worse, while slipping my attention repetetively, I did leave a few track and trace requests by mail at GPA without any reply. I planned to post about that in this forum.

I am really surprised about this since the service has been excellent so far.

Anyway, I made a new sealing ring (gasket?) to place between the units and the horn. When I resetup my setsystem I will measure with and without these.

Any information about the whereabouts of GPA would be welcome.

Regards, Coen

[Earl K]

Hi Earl,
<<SNIP>>

As a matter of fact I never received the GPA replacement diaphragms.

<<SNIP>>

Any information about the whereabouts of GPA would be welcome.

Regards, Coen

Sorry to hear about this . Maybe the diaphragms were simply never shipped .

- GPA is located at ;

GREAT PLAINS AUDIO ™
7127 NORTHWEST THIRD ST.
OKLAHOMA CITY, OKLAHOMA 73127

(405) 789-0221 or (405) 787-0987

- I'm not that surprised GPA didn't respond to your emails ( they're widely known for ignoring emails ) .
- ( It's said ) you have to telephone them to get their attention.

- If you can't get any action on your own , contact Todd White ( this forums webmaster ) and ask if he will intervene on your behalf ( alternately, Altec Best may want a crack at helping you out , so as to help maintain GPA's reputation ) .

<> EarlK

[Coendert2011]

Thanks for the information and tips!

i'm located in Europe so I'll try to phone them this afternoon or next week.

Regards, Coen

[Earl K]

Thanks for the information and tips!

i'm located in Europe so I'll try to phone them this afternoon or next week.

Regards, Coen

Coen, were you ever charged for these 2 diaphragms ?


If not, you may just want to leave "sleeping dogs lay" ( since I doubt you really need a new pair of diaphragms / all things considered ) .

I just ordered two new GPA diaphragms.

They were a bit hesitant to sell them to me, assuming I did not like the 288 character. Kudos to that attitude, wich I think is a good customer relation is all about!
<<SNIP>>

- As you previously stated ( from your first contact with them over this order from post# 81) GPA were hesitant to sell you new diaphragms fearing you may simply not enjoy the legacy sound of the 288 .

- Perhaps GPA figured they were doing you a favour by not shipping you superfluous parts .

<> EarlK

[Altec Best]

( alternately, Altec Best may want a crack at helping you out , so as to help maintain GPA's reputation ) .

You know Earl I'm always here to help anyone who asks for it..

FYI ~ Todd is taking a break from the daily duties.So I can pretty much help anyone with any issues they may have with the Altec User board.