Planar Speaker Asylum Welcome! Need support, you got it. Or share your ideas and experiences.

---

[ Follow Ups ] [ Post Followup ] Thread: [ Display  All  Email ] [ Planar Speaker Asylum ]

---

[ Alert Moderator ]

---

RE: Neo8s ...

Posted by Satie (A) on April 19, 2016 at 20:22:54

In Reply to: RE: Neo8s ... posted by andyr on April 19, 2016 at 17:15:25:

OK

Two things. First is how much baffle are you going to provide them, as you can see in the spec/info sheet (I didn't look to see if they put them back online) baffle loading changes the FR in the sub 1khz range.
Second is how loud you play, the louder you play - the drivers will bottom out at a higher freq. At 126db it bottomed out at 800hz or so with the lower mid going from weak to MIA..At 100 db you are flat to below 300 db and bottom out about 250 hz. Playing to 110 db you will have a slightly weak lower mids but I don't have a solid -3db point for you - I would guestimate that an array of 6 with ample baffle on one side will go to 500hz at 110 db (if you care)
.

The more drivers in the array the lower the freq at which they are usefully additive and the smaller is the gap resonance peak at 11-12 khz. There are still traces of it at 6 per side, none at 9 per side. I should point out that though on axis the FR will roll off at 14 khz with the regular Neo8, the off axis FR of the array will drop off earlier - 3db @ 11-12khz at less that 30 deg off axis. .The PDR version will get to >14khz off axis (well at a reasonable angle) and will ony droop on axis to -3 to 5 db at 20 khz

My solution is to cut off at 150 hz 6db and stretch the bass LP up to 250 hz LR4 or 200 hz B3. That way there is hardly any phase on the driver and I can plug in the ribbon tweeter at the 18khz 1st order (still shares the 150hz HP so is not really exposed to very low freq)

I starte out with B3 symmetrical and equidistant drivers at 300 ant 6khz. I didn't have a head in a vice problem but having measured the off axis FR I wanted to stay out of trouble on the dispersion side. So I pretty much did the same with symmetrical LR4.

I then experimented with letting the driver array play full range (hence my knowledge of when it bottoms out) and just added in the tweeter and bass with B3 and LR4 at various freq between 6 and 12 khz. Never got it to mesh perfectly.

The compromise solution was to go linear phase for the entire speaker, so 1st order symmetrical at 250 hz and appx 8 khz avoided the head in a vice most of the time and had the most perfect imaging I ever heard. Of course with an equidistant arrangement of all the drivers. I think that would be the place to start. You would then only bottom out the mid array at 300hz when playing 110 db peaks (since you are sitting closer - I measured at 3m) It is not bothersome since the bass panels are only 1st order in this setup and fill out the missing bits 250-500 hz perfectly adequately on 110 db peaks.

I experimented with myriad other XOs for different placements. Ask and I will answer if you have anything in particular in mind.

In your version Q1 you have no mid LP - If your drivers are equidistant then you can LP at the same freq as the tweeter. 4 khz is still marginally too low for the ribbon to operate with a 6 db HP, so I would take it up till you have the beginning of dispersion problems - likely 6-8khz. Otherwise the ribbon will show you its displeasure at being driven hard with a metallic sheen to everything. You can try doing the Bass LP at 1st order instead of 3rd and experiment with lowering the LP to 150hz if it is not interfering with .clarity. If the bass' intrusion into the 300 hz bothers you then do cut it off at B3 at 300hz - or even lower. Just that you will no longer be able to have time alignment and you will need to get it in phase carefully according to how your drivers are offset from equidistant.

In Q2 I am guessing that you are offsetting the XO from symmetrical -3db freq to compensate for offsets from equidistant driver placement. If that is not the case the mid-tweeter should XO symmetrically, and up to an octave higher, And the bass LP freq should be matched to get you in phase and compensate for offset.

Go by ear if you have a variable XO and then measure.

If your listening levels are more civilized then you can crossover the tweeter lower and take it to as low as 4khz so long as it has another HP before it in the 100-500 hz range. If you can set it up to share the mid HP then that will simplify it somewhat,

Lots of options

This post is made possible by the generous support of people like you and our sponsors:

Kimber Kable

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---