B&C 18SW115 enclosure design |
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smitske96
Young Croc Joined: 16 February 2016 Location: The Netherlands Status: Offline Points: 1092 |
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Posted: 16 October 2016 at 11:07pm |
In the search for a compact sub i came across the 18sw115 driver from b&c.
On the website of b&c they have a "suggested design" for the 18sw115, but with the ports on the plan there would be a vent speed of 72 m/s (if given 1700 Watt each). After some research i learned that 30 m/s is the max acceptable vent speed? Thinking about the ventnoise I started simulating with winisd alpha. B&C recommend a 150 L enclosure tuned to 35 Hz, The ports in the simulation are 90x450mm with a vent length of 500mm, this time there was a vent speed of 28 m/s. I would like the vent at the side of the cabinet, so the vent would be shelved. After reading some topics on different website's I learned that shelved ports have some influence on the tuning. Knowing this, i simulated the b&c sub18 design, and tried t0 achieve the same tuning (with 18tbx100). By doing this I calculated that the shelved ports need to be factor 0,6 shorter then simulated. Would this be a good guess? Why I chose this driver? I needed a compact sub, that is capable of reaching 30/35 Hz. Also soundquality wise I prefer reflex designs. |
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smitske96
Young Croc Joined: 16 February 2016 Location: The Netherlands Status: Offline Points: 1092 |
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Here are some results from winISD. The rear chamber of the BP is tuned to 35 Hz with a volume of 150 L, the front chamber is tuned to 80 Hz with a volume of 40 L. both have a SPL of 92 dB @35 Hz. (Both don't have a flat response). 36 Hz and up the BP wins in the simulation.
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BASSHORSE
Young Croc Joined: 19 September 2007 Location: wolverhampton Status: Offline Points: 1160 |
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put them in for mini scoops,.job dun
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smitske96
Young Croc Joined: 16 February 2016 Location: The Netherlands Status: Offline Points: 1092 |
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I believe they would work in a miniscoop, but the size is the problem.
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Dubbed-up
Registered User Joined: 16 December 2012 Location: Surrey Status: Offline Points: 119 |
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They definitely do work in mini-scoops.... with a deep chamber.
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smitske96
Young Croc Joined: 16 February 2016 Location: The Netherlands Status: Offline Points: 1092 |
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It will definitely not gonna be a horn or scoop. They are just to big for my applications.
I've read that some BP cabinets are described as slow, but for an example the nexo ls600 or ls18 isn't slow. Could the port lenght have influence on that?
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Crashpc
Registered User Joined: 26 February 2008 Location: Czech Republic Status: Offline Points: 465 |
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Hey there. Quite late. I have 18SW115 in about 130-135l box tuned at 34Hz for home audio. Works good from 35Hz, does some sound down to 29Hz. I believe the length of the reflex doesn´t have to be that short. Propably 0,8. Depends... Best way is to make a prototype box, and if you cannot, best way is to make shorter reflex, and then add pieces to make it longer. Once you secure it well (screws) and seal holes and spaces between those pieces (silicone) it´will lead to your preferred tuning, and nobody will see the inner work anyway.
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Nikon and Canon people should not be married to each other. Why did you let this happen?
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smitske96
Young Croc Joined: 16 February 2016 Location: The Netherlands Status: Offline Points: 1092 |
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Two B&C 18SW115-8 drivers are ordered for some testing. Within a couple of weeks I want to measure two different cabs with REW.
A reccomended cab from B&C is already made from mdf (for testing). If the port noise is to loud (what I expect) there will be build another cab with a bigger (and flared) port. Also the TH-18 from Xoc1 seems interesting.. PS: Testing will be done with a NEXT MQ10000 (bridged) and a EV DC-ONE.
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Crashpc
Registered User Joined: 26 February 2008 Location: Czech Republic Status: Offline Points: 465 |
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Wow, awesome!
I always used B&C speakers, and didnt like its high excursion performance (some unwanted noise coming out of the speaker 12PS100,12TBX100,15PS76,15PS100,15TBX100,18PS76,18PZB100,18TBX100). When mounted in the box, it wasnt audible (mostly), but I was not really happy. Now with 18SW115, its different league. Driven to Xmax of about +-15mm, the cone movement is very "cultivated" with very little (expectable amount) of noise. I was surprised positively with this. They finally DID IT! Good times coming. :-) 150l@35Hz should work, but yeah, the bassreflex area is "thin line walking" with 340mm2. Will loose efficiency when driven with large signal. I got 512 on mine, and that´s where I would say no less for noise free audio. With 21", Ill have to approach 650-700cm2 mark. Edited by Crashpc - 11 January 2017 at 10:40pm |
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Nikon and Canon people should not be married to each other. Why did you let this happen?
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toastyghost
The 10,000 Points Club Joined: 09 January 2007 Location: Manchester Status: Offline Points: 10919 |
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I would recommend the Keystone TH design for that driver if you go that route. There are comparisons to a reflex loaded with the same driver too Edited by toastyghost - 12 January 2017 at 10:08am |
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smitske96
Young Croc Joined: 16 February 2016 Location: The Netherlands Status: Offline Points: 1092 |
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I've read about the keystone sub, but the dimensions are not ideal for my applications.
The Th-18 with its dimensions would be better suited for me. Eventually like al builds there have to be made compromises between SPL,low frequency extension and size. I hope the BR will perform up to my expectations, if that is not the case I will look further (maybe even BP).
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smitske96
Young Croc Joined: 16 February 2016 Location: The Netherlands Status: Offline Points: 1092 |
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I have received the driver's earlier then expected (and that's not a problem )
Today I will play some music over them, measuring will be done next week.
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