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A Speaker that Kicks Butt in Large Spaces
A Speaker that Kicks Butt in Large Spaces
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Old 2nd January 2018, 02:10 AM   #1151
globalplayer is offline globalplayer  Germany
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Quote:
Originally Posted by hoyungh View Post
You are also looking for kick. I think this is represented by energy. in the speaker models energy at resonance is stored as pressure in the helmholtz resonator. the problem then is that at the same pressure difference large speakers store more energy than small speakers. properly designed smaller speakers may sound the same but they will not have the kick (thump in the chest?) you desire. so looking for kick and wanting a small speaker may be mutually exclusive.
For kick out of a helmholtz it needs to be as short as possible.
Also the speaker cone should be in close proximity of the inner port opening.
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Last edited by globalplayer; 2nd January 2018 at 02:22 AM.
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Old 2nd January 2018, 03:42 AM   #1152
freddi is offline freddi  United States
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A Speaker that Kicks Butt in Large Spaces
speaking of vent placement - look at the graphs I just took of a 6-slit vent style Karlson 12 (maybe late 1956-57 - published in July 1958) with Eminence's first B102 vs the first Karlson 12 from fall 1954 which had a single horizontal vent, loaded with Dayton's PA310-8. There isn't a great difference between their front chambers other than the later model had a 10 degree forwards slant.

I think the distributive vent is making the difference. What do you say?

These are very close measurements - like 6" from the aperture - its probably more meaningful (?) to take plots at a greater range than the aperture's height.

Click the image to open in full size.

Last edited by freddi; 2nd January 2018 at 03:54 AM.
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Old 2nd January 2018, 03:58 AM   #1153
globalplayer is offline globalplayer  Germany
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Of course it does.
From my experiments a single slot sounds better than multiples (subwoofers).
On the graph it looks like the single port is more effective although port resonances might mess up spl at the higher frequencies (200+).
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Old 2nd January 2018, 04:54 AM   #1154
xrk971 is offline xrk971  United States
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A Speaker that Kicks Butt in Large Spaces
Hi Freddi,
It looks like the distributed slot has sharper dips, which are less audible. However, they may cause more harmonic distortion in frequency space. Floor measurements remove floor bounce (but not room wall bounce) so needs to be done in an open field not inside a small room. I usually measure at least 0.5m away with speaker on a stand to avoid room and floor bounce. I know you use RTA and Omni Mic. Try using REW and set frequency dependent window (FDW) option to 6 cycles. This gates measurement and makes sure what you see is intrinsic to the speaker and not result of floor or room bounce. It’s really useful to have that feature.
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Old 2nd January 2018, 02:24 PM   #1155
hoyungh is offline hoyungh
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Yes Freddi akabak also indicates changing the ports lengths improves the freq response but my old ears didnt hear any difference. But then anyone looking at the freq response of a K would never believe how good and natural it sounds.
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Old 3rd January 2018, 05:41 AM   #1156
freddi is offline freddi  United States
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A Speaker that Kicks Butt in Large Spaces
what would you suggest as a K-alternative build to K12 and Karlsonator12 which might sound at least as good using say, Kappa12 as the driver?
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Old 3rd January 2018, 04:52 PM   #1157
freddi is offline freddi  United States
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A Speaker that Kicks Butt in Large Spaces
here's my first attempt at REW for two diy Karlsonette (1st K12 cabinets) - neither has substantial damping materials. The cabinet loaded with PA310-8 has its stock ~14" wide by 15/16" wide slot port. The other cabinet, with Pyle PYM1298 (~like Kappa 12A) has the stock port blocked and a rough ~K15 style port of maybe 13 sq. inch. cut into its upper board.


subjectively, although the cabinets were tried in different parts of the room, I thought the Pyle 12 sounded much clearer, faster, and more agile when coupled to a K-tube and compression driver. The Dayton has a good motor, low Q but double the moving mass of pym1298.

(Brain Steele will probably laugh or be aghast at the LF extension compared to TH POC3 and Boom Unit - K12 have about 35l back chamber and tuned around 62Hz)

the cabinets were away from walls a fair amount, and elevated about 33"

Click the image to open in full size.
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Old 3rd January 2018, 05:32 PM   #1158
xrk971 is offline xrk971  United States
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Welcome to the world of REW and nice looking measurements! The FDW 6 cycle shows what is intrinsically happening with the speaker independent of the room. You will see how handy it is to not have to hand type legends in a paint program anymore. You can overlay dozens of plots and click the enable button next to the legend to show or hide - very handy.
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Old 3rd January 2018, 05:41 PM   #1159
freddi is offline freddi  United States
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A Speaker that Kicks Butt in Large Spaces
THANKS ! - it sure will help make decisions vs 18 million squiggles - that pc must be 15 years old, and has 768MB ram - program seems to run fine on xp.

I need to take a factory Karlsonette, remove its port panel, then cut something close to the "Dutch K12" 3 - slot port for comparisons.

Last edited by freddi; 3rd January 2018 at 05:44 PM.
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Old 4th January 2018, 07:47 AM   #1160
freddi is offline freddi  United States
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A Speaker that Kicks Butt in Large Spaces
here's a few more from the K-pile


Low qts SWR 10" bass guitar speaker from Eminence in a 0.62 scale K15 vs PYM1298 in a K12
Click the image to open in full size.

K12 with PYM1298 again vs a high aspect K8 with 3" port at the top and Nirvana Super 8 vs Art Welter's Dad's "K8" with a Visaton BG20.

there is something screwy with the tall K8 and port near the top

Click the image to open in full size.
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