Ricci's dual B&C 21SW152 build thread. - Page 2 - diyAudio
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Old 6th April 2010, 09:57 PM   #11
tb46 is offline tb46  United States
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Default Correction Post #8

Hi soho54,

You are correct S2 about 1/2 Sd. Thanks.

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Old 6th April 2010, 10:05 PM   #12
soho54 is offline soho54  United States
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I typo-ed. The 4 segment S4 should be Sd x1.75, not x1.5
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Old 6th April 2010, 10:42 PM   #13
tb46 is offline tb46  United States
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Hi soho54,

Such is life :-), this is just very general anyhow.

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Old 7th April 2010, 08:53 PM   #14
FlipC is offline FlipC  United States
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Cant believe I wasn't around when you posted this.
Just got finished building 4 Apache H15's (TH's)
I have a TH for these subs. Here is the HR date:

ID=23.40
Ang=2.0 x Pi
Eg=60.00
Rg=0.00
Fta=4.03
S1=336.00
S2=880.42
Con=10.00
F12=0.00
S2=880.42
S3=5000.53
Con=500.40
F23=0.00
S3=5000.53
S4=6000.00
Con=54.00
F34=0.00
S4=0.00
S5=0.00
L45=0.00
F45=0.00
Sd=1680.00
Bl=32.60
Cms=6.30E-05
Rms=10.70
Mmd=437.80
Le=1.30
Re=3.30
TH=2P
Vrc=0.00
Lrc=0.00
Ap1=0.00
Lpt=0.00
Vtc=0.00
Atc=0.00
Com=FlipC -TH 221 Clone B&C 21SW150 4 Ohm 1500w 15mmXmax 60v

Good down to 18Hz at 125.5 DB !
130 DB at 20 hz.
Design has plenty of room to play with power also though that is at a respectable power level for such big drivers.

Something I will build myself one day! I cant afford to right now.
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Old 7th April 2010, 10:19 PM   #15
soho54 is offline soho54  United States
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FlipC, try this one out.
Attached Files
File Type: txt twobc21.txt (415 Bytes, 44 views)
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Old 8th April 2010, 05:30 AM   #16
FlipC is offline FlipC  United States
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soho54
A bit give an take there.
I went on the assumption of having a small dip. Seemingly they get filled in the real world.

I did another where the Impedance is exact to the DLS TH 221.
Though the output isn't the same. Not good at all really. I am left to think that DLS has something not so easy going on inside of their bigger TH's.
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Old 8th April 2010, 09:18 PM   #17
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Hey guys. I've got the 8ohm versions. Here is the PDF. I put a dmm to the drivers last night and they both come out exactly at 6ohms. the modeling doesn;t appear too much different.

21SW152-8.pdf


Here are some notes I reported over at AVS.

I also free air tested both to see if there were any issues. I decided to push them fairly hard in the mean time. They are really clean and noise free up to what looks like about the rated xmax 25-30mm p2p they start to make some suspension noises past there and a good amount of air noise from the motor. I pushed them on up to maybe 40-45mm p2p at which point there is a large amount of self noise from the suspension and motor vents. The amount of air coming out of the back of the motor is very impressive. Should be some good gap/vc cooling going on there.

Interestingly I was using a single channel of a QSC PL9.0 during this free air test and a 10hz sine as it provided the most excursion with the least amount of volume. The single PL9.0 channel hits hard clipping before the speaker gets in any danger of bottoming. Figuring that it's probably about a 9ohm load at 10hz that should be somewhere north of 1600w of a 10hz sine wave in free air producing about 40mm p2p. It appears that these are not an easy driver to get into excursion trouble which makes me happy, as I was worried about that if used in a sealed alignment with LT(which a lot of people talk about). The suspension appears to rapidly put the brakes on at around 20mm one way judging by the behavior of the last couple of volume increases. I'd guess that you'd have to break something in the suspension before reaching 30mm and hitting the back plate.
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Old 8th April 2010, 09:22 PM   #18
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What about this 400L TH simulation? I think it looks ok. I'd be filtering it around 20-25hz. Compression is still up at 3/1, but the cone seems really thick and strong on these.


21sw152-8 30hz 400L TH.JPG
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Old 9th April 2010, 04:15 AM   #19
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Why are you simulating in 4,0 pi? 2,0 Pi will make things a lot better and is closer to real conditions as long as the subs are ground based.
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Old 9th April 2010, 04:51 PM   #20
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Personal preference. I always sim in 4.0pi. It's irrelevant anyway. The basic performance characteristics of the system design does not change.
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