north creek d28

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has anyone tried the north creek d28 tweeter, would you say its the same as usher 9500 or scan 9500.
george at north creek has them at a good price.
it will be used in active system with volt bm2500.1 bass mid unit (which i'm more than happy with)
the crossover freq is 1700hz
can i expect some improvement over audax hd13d34 (34mm tweeter).
by the way used opamps in x/o and LT circuit.
ne5534 is good
opa134 better
free sample opa627 horrible sound
 
if the D28 is a copy of the dynaudio it should be good. of the 3 i have only used the scan 9500 and yes you should get a lot more resolution that the 34mm Audax dome.

lastly I find OP275 MIL to be adequae for my XO needs. 5532/5534 come close. Then again I made my XO in 1995 so a lot has changed since then.
 
yes now have tried a pair of north d28-06 tweeters.
did a straight substitution into my active speakers just to see what they were like, at first sounded worse than my equalised audax tm025f1, somewhat disapointed !
the audax has a rising topend, about plus 6db by 17khz and also a highish resonance at 1300hz with q about 1.3
one thing i did notice straight away was a definate improvement in what i'd call compression distortion at higher volume levels with the northcreek tweeter.
thought i'd let em run in for a week and do some response measurements.
nearfield, farfield etc
found nearfield to be similar to northcreeks published curves,
however far field with baffle influence shows quite a step up in level at around 6khz to 8khz, about 2.5 db
tried eq at first, then changing baffle proportions.

one of the reasons i wanted new tweeters, is that i dont like pronounced sibilance.

6-8khz is sibilant zone, thought i'd wasted my money

however I now have them sounding great. I'm a great believer in technical spec and thought these tweeters should sound good, what can be wrong?
started by leaving tweeters to run unequalised and slight modified crossover slope on bass mid unit.
redesigned baffle to bring a diffraction peak into depressed 2k-5khz zone.
built some gainclone type amps for treble.
disposed of passive stepped attenuator for volume control.
swapped around with opamps ne5534, opa134, opa627,
impedance compensated opamp inputs and made one buffer class a
built active volume box
tweeked crossover a bit more.

can now listen to speakers with flat gated response (ie not attenuating treble to remove sibilance). find detail to be excellent
most interesting listening to live radio, all the microphone techniques show up and people licking their lips and gnashing their teeth. dont need to play loud to get this detail but turn them up a bit and their is no distortion increase.

how much this is due to 'burn in' or modifications I'm not sure.
but I now dont feel the urge to twiddle with driver levels at every change of track.

there can be some improvement yet but im not sure how to acheive this.

value has been good but after paying customs and post office another £25 I could have bought a pair of scan 9500 from my local shop for the same price. (also the scans dont seem to have the rising treble, will probably get some of these later)

all in all now quite happy, but have learnt that audax tmo25f1 is a fine tweeter for the money and the northcreek has some competition at the price.

I'd just like to say that northcreek have provided an excellent service in the dealings I had with them and am sure they are honest and what their website says you can trust.
I can only imagine how good their kit speakers must be with proper professional design put into them.
 
oh just one other thing,
I think we must all get used to the sound we hear and if there is a fault then it will stand out. this can sometimes be improved by cutting out the frequency that conveys this fault.

I wasnt happy with filtering the sibilance out of my speakers as i lost detail with it to.

now the faults i hear are beyond my control at the recording end, its easy now to hear thats where they lie.

unfortunately all the other speakers i listen to have taken on a really sibilant sound overnight !
 
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