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Exakt Filter Variants
2017-08-23, 13:27
Post: #41
RE: Exakt Filter Variants
(2017-08-23 13:03)Phil Budd (Philbo) Wrote:  The resonance of the bass driver in the cabinet is 82 Hz and that does indeed define the natural -3 dB frequency of the driver in its cabinet. The - 6 dB point is around 74 Hz with no augmentation.

However, as the cabinet is sealed and forms a pretty stiff air spring behind the unit, it is quite viable to add gain below this frequency to extend the low frequency performance of the speaker without risk of damage to the unit. This was done in both the Aktiv and Exakt designs.

The Exakt design has a - 6 dB point at about 50 Hz in free space so will be expected to be around 35 Hz in room.

Fascinating - thanks for these additional insights! Big Grin

I'm assuming you have comparable figures for the Keilidhs that you could share with us.

If the resonance of the bass drivers is taken care of by Exakt then I'm assuming there is no requirement for custom room modes in SO+ to address this??

I know, I've used the word "assuming" twice ... ! Big Grin

Unidisk SC | Majik LP12 | Trampolin 2 | Lingo 3.
Akurate DSM | Akurate Exaktbox 10 | 2 x Akurate 4200/1 | Exakt dual-mono Keilidhs
Raspberry Pi 2 Model B | IQAudio Pi-DAC+ | Audiolab 8000A | AR28s.
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2017-08-23, 13:36
Post: #42
RE: Exakt Filter Variants
(2017-08-23 13:27)Donald Wrote:  
(2017-08-23 13:03)Phil Budd (Philbo) Wrote:  The resonance of the bass driver in the cabinet is 82 Hz and that does indeed define the natural -3 dB frequency of the driver in its cabinet. The - 6 dB point is around 74 Hz with no augmentation.

However, as the cabinet is sealed and forms a pretty stiff air spring behind the unit, it is quite viable to add gain below this frequency to extend the low frequency performance of the speaker without risk of damage to the unit. This was done in both the Aktiv and Exakt designs.

The Exakt design has a - 6 dB point at about 50 Hz in free space so will be expected to be around 35 Hz in room.

Fascinating - thanks for these additional insights! Big Grin

I'm assuming you have comparable figures for the Keilidhs that you could share with us.

If the resonance of the bass drivers is taken care of by Exakt then I'm assuming there is no requirement for custom room modes in SO+ to address this??

I know, I've used the word "assuming" twice ... ! Big Grin

...and an additional query please Smile

Philbo Wrote:However, as the cabinet is sealed and forms a pretty stiff air spring behind the unit, it is quite viable to add gain below this frequency to extend the low frequency performance of the speaker without risk of damage to the unit.

Does that imply that if a seal perishes with age that there's a chance Exakt will cause damage to the driver?

ADs/2 -> Klimax Exaktbox/1 -> Silvers -> 2xKCT/D -> K200 -> Ninka
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2017-08-23, 15:52 (This post was last modified: 2017-08-24 10:37 by Phil Budd (Philbo).)
Post: #43
RE: Exakt Filter Variants
(2017-08-23 13:27)Donald Wrote:  I'm assuming you have comparable figures for the Keilidhs that you could share with us.

The natural resonance of the Keilidh bass system is actually rather lower than in the Kaber so with Exakt augmentation the -6 dB corner, in room, is around the 30 Hz mark.

(2017-08-23 13:27)Donald Wrote:  If the resonance of the bass drivers is taken care of by Exakt then I'm assuming there is no requirement for custom room modes in SO+ to address this??

Resonance in this sense is not really comparable with a room mode. The bass driver in the Keilidh has a Q factor of about 0.8. A room resonance will likely have a Q factor of 20+. Since the resonance of a bass system is modeled in Exakt it is fully corrected anyway.

(2017-08-23 13:36)phino Wrote:  ...and an additional query please Smile

Philbo Wrote:However, as the cabinet is sealed and forms a pretty stiff air spring behind the unit, it is quite viable to add gain below this frequency to extend the low frequency performance of the speaker without risk of damage to the unit.

Does that imply that if a seal perishes with age that there's a chance Exakt will cause damage to the driver?

The failure mode you mention would be true of any augmented system, Aktiv or Exakt, and may also cause problems in a passive system. That said, bass units are pretty robust, it tends to be sending them high current DC that causes failure.
It is worth noting that in most instances when I apply bass augmentation in an Exakt design I will add a linear phase high order roll-on at very low frequency (assuming I have the processing headroom).

Phil.
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2017-08-24, 16:34
Post: #44
RE: Exakt Filter Variants
Thx Philbo - matches with my suspicions & what my ears tell me. I like a sub with the Kabers, in my current room the crossover set at about 65hz. Happy to see the Kaber Exakt models include a sub and looking forward to take that route eventually.

Also I have a thing for 4 Inch drivers running more or less full range, one of my other speakers is a Needle with a TangBand W1320. The Kaber mids seem to cover 90-2500hz, quite a range.

http://www.last.fm/user/mcgillroy

MDSM/2 - 6100/D - active Kabers - Nubert 441w sub + Qobuz Sublime.
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2017-08-31, 11:00
Post: #45
RE: Exakt Filter Variants
I have exakted Ninkas (w/ Klimax Katalyst Exaktbox) and just ordered an Akurate Exaktbox 6 and Exaktbox Sub for my Ekwal and (single) Sizmik 10.25 for Exakt Surround. I was planning to use the Sizmik only for Surround but am wondering now if it should be an improvement to music / stereo as well - as indicated for Kabers above. So far I have not been missing anything w/o the sub in stereo...

Are there comparable figures for Ninka? Would those support the use of a sub in stereo?
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2017-08-31, 13:03
Post: #46
RE: Exakt Filter Variants
(2017-08-31 11:00)TimB Wrote:  I have exakted Ninkas (w/ Klimax Katalyst Exaktbox) and just ordered an Akurate Exaktbox 6 and Exaktbox Sub for my Ekwal and (single) Sizmik 10.25 for Exakt Surround. I was planning to use the Sizmik only for Surround but am wondering now if it should be an improvement to music / stereo as well - as indicated for Kabers above. So far I have not been missing anything w/o the sub in stereo...

Are there comparable figures for Ninka? Would those support the use of a sub in stereo?

It is pretty simple to try both options, it is just a case of changing the settings for the subwoofer in Konfig.
A sub will always add low frequency power to the system, whether or not it adds much in terms of frequency extension. That said the Sizmik will go lower than the Ninka.

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2017-09-13, 09:17
Post: #47
RE: Exakt Filter Variants
Speaking of toe-in, does the advice to have the same amount of toe-in for each speaker still hold if the listening position is off-centre?

ADs/2 -> Klimax Exaktbox/1 -> Silvers -> 2xKCT/D -> K200 -> Ninka
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2017-09-13, 09:31 (This post was last modified: 2017-09-13 09:40 by Donald.)
Post: #48
RE: Exakt Filter Variants
Ramblings deleted - sorry!

Unidisk SC | Majik LP12 | Trampolin 2 | Lingo 3.
Akurate DSM | Akurate Exaktbox 10 | 2 x Akurate 4200/1 | Exakt dual-mono Keilidhs
Raspberry Pi 2 Model B | IQAudio Pi-DAC+ | Audiolab 8000A | AR28s.
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2017-09-13, 12:12
Post: #49
RE: Exakt Filter Variants
(2017-09-13 09:17)phino Wrote:  Speaking of toe-in, does the advice to have the same amount of toe-in for each speaker still hold if the listening position is off-centre?

Not usually - adjust to suit by experimenting, but the toe-in on the nearest speaker is likely to be less. However, other elements in the room, such as how close the speaker is to the side wall, furniture items etc., will also influence the amount of toe-in.

At Scalford earlier this year I found the RH speaker needed a little more toe-in than the left, probably due to the step in the RH wall (the room got narrower due to a built-in wardrobe) just about in-line with listening position. Both of them needed more toe-in than used at home, probably due to the side wall being closer.

Main: AK/0/D; AEDSM; MeiCord AExaktbox10; Silvers 2x A4200/1; K400 NSL Exakt dual-mono PMC Twenty.26; Twenty.C; Blacks AV5125 PMC Twenty.21
Playroom: SBT; V-DAC1; Cyrus6; M773e
Garage: SBT/Rega DAC; Arcam AVR100; 2x AV5125; Aktiv Ninkas, Trikan, AVSeKretan
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2017-09-13, 14:44
Post: #50
RE: Exakt Filter Variants
(2017-09-13 12:12)sunbeamgls Wrote:  
(2017-09-13 09:17)phino Wrote:  Speaking of toe-in, does the advice to have the same amount of toe-in for each speaker still hold if the listening position is off-centre?

Not usually - adjust to suit by experimenting, but the toe-in on the nearest speaker is likely to be less. However, other elements in the room, such as how close the speaker is to the side wall, furniture items etc., will also influence the amount of toe-in.

At Scalford earlier this year I found the RH speaker needed a little more toe-in than the left, probably due to the step in the RH wall (the room got narrower due to a built-in wardrobe) just about in-line with listening position. Both of them needed more toe-in than used at home, probably due to the side wall being closer.

Thanks Neil. I'll feel free to experiment then Smile all the Linn advice seems to say keep them the same and the same distance from the wall.
I rearranged my room the other day and now my speakers are much farther apart on a different wall. Prior to that I've always preferred very little to no toe-in at all, but now it's making a huge difference - and for the better I think (so far)

Nb I've no idea why my post ended up in this thread, I'm almost certain I was adding it to the end of the Exakted Killer Keltiks thread!!!

ADs/2 -> Klimax Exaktbox/1 -> Silvers -> 2xKCT/D -> K200 -> Ninka
Exaktbox Sub - BK Sub
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