121 wedge/top cab help needed
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Category: Plans
Forum Name: New Projects Forum
Forum Description: Forum for new speakerplans projects, in memory of Tony Wilkes, 1953 - 2014
URL: https://forum.speakerplans.com/forum_posts.asp?TID=19385
Printed Date: 26 March 2026 at 10:56pm
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Topic: 121 wedge/top cab help needed
Posted By: dlyxover
Subject: 121 wedge/top cab help needed
Date Posted: 01 September 2008 at 4:14pm
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Im working on this design but am unsure of some of the figures and hoping that someone can help me.
I got the initial measurements from a CS121 (concert systems) i spoke to them and was told the logic systems made the boxes for them. Im using WinISD online and a B&C 12NDL76 and DE250 and this is what I've come up with 
I think the box volume is 52L and tuned to 73Hz, using the paramiter from the B&C website Vas :- 73 Qts :- 0.20 Fs :- 50Hz I know the port length is wrong I think it should be 8.146mm not 115mm as on the plan. If anyone can point out any rookie errors it would be appreciated. |
Replies:
Posted By: dlyxover
Date Posted: 16 September 2008 at 7:24pm
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i have changed the design a little changed the box volume for 52L to 37L (including port and speaker volume) and kept the tuning frequency the same (73HZ)
the results are as follows
frequency responce
 SLP
 phase
 group delay
 I know i want the frequency responce to be flat or as near to as possible but how much give is there in that?
How do you you put trangluar ports in on winISD?
Can anyone help me?
any input is welcome
thank you
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Posted By: darkmatter
Date Posted: 17 September 2008 at 12:54am
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re. triangular ports, you'd just calculate as if they were square, working out the equivalent dimensions of a square port and using these in winisd. i seem to remember someone mentioning that a triangular port can be viewed as very slightly smaller than it's round/square equivalent. this is because the sharp angled corners have higher resistance/losses than a round/square port would. can't really comment on tuning decisions, as i've only built one pair of monitors. i used B&C 12HPL76 and B&C DE250, around 58litres (not including port, driver, horn etc) tuned to 60hz. i've not measured impedance plots or freq response, so im not sure whether that's the true tuning, but i'm happy with them  |
Posted By: ceharden
Date Posted: 17 September 2008 at 9:03am
| All looks pretty sensible. I reckon you need to build a prototype...... |
Posted By: Robbo
Date Posted: 17 September 2008 at 9:31am
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Just to complicate things even more---Are you intending to use them as a multirole cabinet?
If you are then you need to adjust the angles on the back of the cabinet as you appear to have two 45 degree angles at present---these need changing to 30 degrees on one side and 60 degrees on the other as wedge monitors at a 45 degree angle do not work as they will be pointing at performers knees and not their heads on most stages. To hear a 45 degree wedge effectively, you have to be about 6 to 8 ft away from it and you will find that you would rarely be able to use them at this distance whereas a wedge at 30 degrees can be tucked up pretty tight against the mic stand base,will be pointing in the right direction and will also be a lot closer to the performer.
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Posted By: nickyburnell
Date Posted: 17 September 2008 at 9:47am
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Anybody got plans for a 12" wedge? I've found a few, but no angles etc in the drawings? ------------- It's everything, not everythink! |
Posted By: dlyxover
Date Posted: 17 September 2008 at 11:15am
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will do ceharden just got to get the drivers.
I've used a 40 degree angle on both side as per the cab Im cloning. The cabs im cloning Ive used as FOH and and wedge (more as wedges) and been really impressed. I will have a play with the angles and see what happens cheers robbo |
Posted By: H...
Date Posted: 17 September 2008 at 12:15pm
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1: I would be thinking of a squared front for my horn so i could change the dispersion between FOH & Monitors - IE Nexo PS15
2: If you keep with the angles of the box then your going to need some accoustic compensators - IE SSE Beta max / Clare Brothers 12AM
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Posted By: dlyxover
Date Posted: 17 September 2008 at 12:39pm
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what do you mean by acoustic compensators?
I've looked at the mentioned products but don't understand |
Posted By: dlyxover
Date Posted: 18 September 2008 at 3:09am
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H
Ive been think about what you said about the rotational horn and I agree, The only 60x40 rotational horn I can find that will fit is the eminence LT250 I was going to go with the beyma TD245. But im not sure how that will effect the sound (are the eminence horns any good?) still trying to find more out about acoustic compensators cheers |
Posted By: H...
Date Posted: 18 September 2008 at 10:54am
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accoustic compensators = blocks of wood / steel poles to change the angle of the box so its pointing at the artists ears!
60 x 40 horn is the way to go for a wedge or if you want nexo ps style its more like 100 x 50.
Have a look at these P-audio horns PH170, PH180, PH220, PH94, PH942, PH64, PH642, PH305 - All can be rotated.
PH64 & a BMD740 would be a good choice
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Posted By: H...
Date Posted: 18 September 2008 at 10:56am
| OR you could make a HF baffle that rotates |
Posted By: dlyxover
Date Posted: 19 September 2008 at 2:35pm
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there is not enought room to have a rotating baffle.
I been looking at using a BMS 12N620 http://bmspro.com/fileadmin/bms-data/product_data/cone_drivers/neodymium/5_8_12/bms_12n620_t.data.pdf will post a plot of it later. has anyone had experance with BMS? driver whats the general thought on them? |
Posted By: dlyxover
Date Posted: 19 September 2008 at 3:29pm
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Blue is the B&C 12ndl76 and green is the BMS 12n620
 Ive tryed the plot the with BMS 12n610
 It looks better to me, I think changing the tuning frequency to about 65Hz will tame the low end peak.
what do people think?
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Posted By: Howie
Date Posted: 25 October 2008 at 2:38am
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I'm finding this quite interesting. I have a pair of the big brother version of these (CS152) loaded with jbl 2226 15" and rcf 850 2", which were the original drivers as far as I know.
I with agree that the angles work fine for monitor use, but they usually end up being used as drum fill or foh.
A bass player freind of mine (yes you, Foggy) turned his amp down because the he preferred the sound of his bass coming from these cabs that were pointing at the drummer! ------------- http://www.gigrighire.co.uk |
Posted By: dlyxover
Date Posted: 25 October 2008 at 10:43am
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I use those cabs all the time sound great weight loads tho. I normally use them on FOH with the 2x15 push pull sub. Did the place theater in manchester the other day with 2 stacks a side ran off crown 3600vz.
I was wrong about the angle, as robbo said it is 30 degrees for 40 |
Posted By: airbell
Date Posted: 31 January 2012 at 11:17pm
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diyxover: Its because the b&c has more spl in mids.look at the real spl plot at 1watt or max spl plot, then you ll see its almost the same spl in bass. bms seems better above 1,2khz because of less mH... |