North Creek D28 + Peerless Hds-164 Nomex

[Klimon]

Hello,

I'ld like to rebuild a lovely pair of transmissionlines (first ones I built) with the peerless hds-164 nomex (which has the right specs for the cabinets) + North Creek D28 I purchased.... Do you think these can be paired using a first order crossover?

Muchos gracias,

Simon

[crazyhub]

Originally posted by Klimon
Hello,

... hds-164 nomex (which has the right specs for the cabinets) + North Creek D28 I purchased.... Do you think these can be paired using a first order crossover?

Muchos gracias,

Simon

Yes, I don't see any reason you couldn't, however take care on Fx, even this tweeter doesn't love high levels with such a resulting feable slope. Shouldn't need a Zobel.

[Klimon]

Fantastic! That should make things doable for me (my ears are my best testing equipment). Would you give an educated guess about crossover frequency? On the previous two-ways I tinkered with I had best results laying the - 3db point of the tweets a couple of khz above that of the woofers. E.g. in this case I'ld probably start with 1,5k for the woofers and 3,5k for the tweeters. Your opinion is much appreciated.

Cheers,

Simon

[sreten]

Originally posted by Klimon

... Do you think these can be paired using a first order crossover?
Simon

Hi,

In a word no. Not properly.

http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://www.geocities.com/woove99/Spkrbldg/

/sreten.

[crazyhub]

Originally posted by sreten


Hi,

In a word no. Not properly.

/sreten.

I guess because of the un-possibility to get correct mismatched phases with first-order x-over regarding the shape of the woofer in its upper-range, isn't it?

[sreten]

Originally posted by crazyhub

I guess because of the un-possibility to get correct mismatched phases with
first-order x-over regarding the shape of the woofer in its upper-range, isn't it?

Hi,

Simply put you do not know the resulting acoustic order of
your crossover slopes and hence phase matching. There are also
issues of BSC (baffle step compensation) and tweeter distortion.

www.zaphaudio.com is as good as any regarding croosovers.

/sreten.

[Klimon]

Thanks for the hints

Simon

[Inductor]

Originally posted by Klimon
Thanks for the hints

Simon

Do you have the drivers already? (You have North D28.)
The SS 6-1/2" Midwoofer 18W/8545K00 is also a great speaker driver.

[sreten]

Hi,

There seems to be a number of HDS164 driver models .....

http://www.northcreekmusic.com/Drivers/NorthD28-06S.PDF

Suggests 2nd order electrical on the tweeter at around 2Khz.
Efficiency will be low so due to L-pad values you likely will not
need the additional parallel LCR for the D28's impedance peak.

This suggests to me your target is the classic 4th order L/R with
some assymetry to manipulate the phase due to driver offsets.

/sreten.

[Klimon]

The SS 6-1/2" Midwoofer 18W/8545K00 is also a great speaker driver.

The Peerless has T/S specs that would be suited for the existing enclosere, anyway I don't have to check the SS price to know I can't afford it

...Suggests 2nd order electrical on the tweeter at around 2Khz.

In the application notes there's something about a certain ratio between L and C (forming the second order low-pass) which they recommend; on investigating George Short from northcreek informed me that on their commercial speakers with D28 they use that ratio e.g. Kitti Cat 11µF and 0,315mH (more info on that crossover is on their website) ; Eska 7µ and 0,5m. Adding: The correct choice of C and L depend on the net tweeter + L-pad resistance. For a higher net impedance, C gets smaller and L gets bigger. For a lower net impedance, C gets larger and L gets smaller. Apparently that ratio sounds best for the D28; Kitty Cat has Fx 1,65 and acoustical 3rd order highpass mated with electrical 2nd order for the midwoofer which results in 3rd order lowpass also. Ideally I'ld like to use that ratio for the tweeters X-overs but I'ld probably need to use simulation software for determining the precise value given the specific L-pad needed for matching the hds164. See here: http://www.northcreekmusic.com/Kitty..._Kat_Info.htms given I'll investigate further later on, meanwhile any input is welcome.

Cheers,

Simon