pushing a 15" driver higher for crossover

[charlie2]

trying to work with this cabinet at present JBL 4638 twin 15"

now I have a couple of previous posts regards this. (jbl 4435 knock off)

But what i am looking into is, as i have the cabinet vertically unlike horizontally (jbl 4435)

lower driver crossed around from 20---300hz

next driver 20---1500hhz plus

there is a 600hz null with this cabinet center-center spacing.

the waveguides I have are the jbl/pyle 612 econowave now previous advice was that waveguide could not go low enough.

so i had a brainfart

the KEF concord back in its day

the nexo to this day

also this post on diyaudio that went dead https://www.google.co.uk/url?sa=t&r...d.html&usg=AFQjCNH7OkEBLUoPxkL1Ai52FoFbucultA

with good input from bjorno a member on here who provided this tech spec (could someone put his results/findings into plain text please)

An externally hosted image should be here but it was not working when we last tested it.

here is some drawings of what i was thinking (DSP INVOLVED REGARDS DELAY XOVER)

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

basicly having the compression driver and waveguide mounted on the driver but protuding quite a bit forward from the baffle.


if i have not put it into words right please say

 

[charlie2]

jbl 2035hpl

the two 15" DRIVERS ARE jbl2035hpl

I can't find any frequency response graphs for these online, sent a request to JBL but no response from them.

a poster on audio heritage said they are good up to 1200hz

DJK on here mentioned this JBL eon aperature anyone tried these

 

[charlie2]

well after a few measurements here is where i am at

made a nexo directivity guide



all measurents raw no eq or crossover

measured on axis then 20/30/40/50/60/70 degrees without guide




.
.
.

.
.

and here with the guide





will have to measure verticaly next (cabinet laid)



















But I could here a distinct difference verticaly between top driver and CD waveguide mounted on top of cabinet

 

[charlie2]

Well to be honest I made a right hash of the measurements.

I changed the active crossover to bypass on the wrong miniDSP

bells should have rung with such a good roll off

 

[GM]

Raw measurements line up with impedance, so need to find out what's causing all the HF 'ripple': Home Theater Overhaul: JBL Pro L/C/R Build

Reflections off the frame, cone breakup or........? Otherwise not sure how well a simple phase plug will help.

GM

 

[charlie2]

Raw measurements line up with impedance, so need to find out what's causing all the HF 'ripple': Home Theater Overhaul: JBL Pro L/C/R Build

Reflections off the frame, cone breakup or........? Otherwise not sure how well a simple phase plug will help.

GM

realy appreciate the input GM

here is a photo of the cabinet, drivers are not flush mounted, but are 15mm from baffle proud

sides protude about 8mm infront of baffle



I can router the sides flush and recess the drivers into the baffle?????

could you please explain further the high frequency ripple you refer to (at what point do you call HF)

cheers


ps center to center is 18"

 

[manninen]

eminence deltalite 15" is one of highest going 15"
i set and tried to play it to 2k, it beams and response is ok but it´s not so hifi sounding played so high.

http://www.diyaudio.com/forums/multi-way/277565-legis-horny-tales-8.html#post4568737

 

[GM]

The HF peaks in the impedance plot.

GM

 

[charlie2]

The HF peaks in the impedance plot.

GM

Hi GM I am a lttle confused as what you are refering too?

I have not posted any impedence plots just response graphs.

please forgive me,

if you are refering to the graphs I posted, then at what frequeny do you call (HF)

or is it the link you provided that you are refering too.

many thanks

 

[GM]

Greets!

The ones in the link I posted.

'HF' in the sense that it's the upper BW of the woofer and in particular, the BW above the driver's upper mass corner where the cab's impact on the driver's performance has faded away [Fhm = ~2*Fs/Qts], so only the driver's forward radiation.

GM

 

[kenpeter]

http://www.americanradiohistory.com/Archive-Radio-Electronics/50s/1955/Radio-Electronics-1955-10.pdf
Pages 54-57

Mind you, any trick that eliminates beaming and widens dispersion,
is going to reduce the audible level of mids. You'll need to equalize.
The benefit, equalization now behaves much the same everywhere.

 

[GM]

With a [very] little help from me [I was 10], that's the article my neighbor built his Karlson from and gave me my long lasting, mostly negative opinions of them. Thanks for the 'walk down memory lane'!

ROTFLMAO reading the tongue-in-cheek 'Variable-Height Fidelity' [pg.57]. It's a really sad 'state of affairs' that it's still relevant today.

GM