xtro style single kick bin...advice...? |
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drivebycar
Registered User Joined: 28 April 2008 Location: United Kingdom Status: Offline Points: 440 |
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haha ok!
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illex
Registered User Joined: 30 January 2008 Location: Greece Status: Offline Points: 50 |
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Finally!!!! I managed to finish the cab. First impressions was not very good as there are some problems with the original design. The bottom part of the throat was vibrating like crazy, thus giving this "honky" sound. Though after adding an extra piece to extend the middle brace till the begining of the bottom part of the throat - in front of the driver - the vibration was gone together with the "honkiness". Also the placement of the handles without a midlle support inside the empty part in front of the throat was quite a bad idea. The empty chamber with the handle holes there was acting like a passive reflex port of some kind. You could here sound coming through the handles!!! But finally that was filled completely with pu foam and sound ok now. So after these modifications I think the cab sounds quite good, it kicks quite well though i'm not shure about fast basslines , they seem to sound a bit muddy. I dont know if this is a problem with the ndl76 driver, the design itself or the place i am doing the tests. That is quite bad for that purpose indeed, it is a 20sqm space with loads of windows and a few metal plate walls!!! I also did a basic measurment with the wrong microphone though. It is an sm57 that has a 5db decrease from 200hz to 100hz that's why the measurment plot is quite off on the lower side.
I will do an other measurment next week with my friends ecm8000 though. Also we have an outdoor party today with the rest of the system, if the cab fits in the van i will take it with me to do some proper listening outside. |
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LjudLahger
Young Croc Joined: 31 July 2008 Location: Sweden Status: Offline Points: 838 |
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Hello, so what's new? Have you done another test yet? Maybe I will try this one for my WN-15s but I want to here more revues from you...good or bad?
And have you heard an Xtro to compare with? //Swe |
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illex
Registered User Joined: 30 January 2008 Location: Greece Status: Offline Points: 50 |
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Hi, i did another test with the right microfone this time, but still inside my workspace.
Here's the plot: This one looks more realistic than then the previous plot with the sm57, though it still drops quite a lot below 130-140 hz that it is not the case with the hornresp sim tha drops around 110-120. Do u think i am doing the measurment wrong, apart from the fact that it is inside a small space? I just place the microfone 30cm in front of the cab on a mic stand. Should I be doing this on the floor in order to have a half space plot? And no, i havent heard an xtro. The only kickbins I've heard is hd15 and some random w-bins. So from my experience i am quite pleased. I am a bit concerned though if two of them wont reach to 90hz to meet my punishers nicely. Do u think I should change the plan? Or it's just a matter of my bad measurment technique. A bit biger front chamber maybe...? I allready made some adjustments to the plans (5cm longer and better bracing) and will start building 4 of them this to next week (if i dont sweat to death , cause the heatwave is here to stay and i'm on the top floor with no airconditioning). I will post the modifications in a bit, or if u need any more detailed plan let me know. thx |
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illex
Registered User Joined: 30 January 2008 Location: Greece Status: Offline Points: 50 |
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Here's the latest plan.
Since the cab with driver is quite light i thought I could do it in 18mm and the total length is now 90cm instead of 85. That makes the horn length 51cm instead of 47 that according to hornresp adds a bit of spl and a more even curve from 120hz to 300hz. I also extended the middle brace cause the part in front of the baffle was resonating like crazy without it, and changed the placement of the handles. It's a 5 cm deep triangular box that also acts as a baffle brace. Any opinios about handle placement guys? Is it a bad idea to have the handle "box" touching the baffle? thx |
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Saul
Old Croc Joined: 15 June 2007 Status: Offline Points: 5912 |
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now that looks tidy biscuits you might want a hole for your driver tho.
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Jake_Fielder
Old Croc Joined: 08 October 2007 Status: Offline Points: 4231 |
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Saul - you just love biscuits too much
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Saul
Old Croc Joined: 15 June 2007 Status: Offline Points: 5912 |
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i know, ive been told i need help, hob nobs, digestves, woodworking biscuits are a favourite tho
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illex
Registered User Joined: 30 January 2008 Location: Greece Status: Offline Points: 50 |
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It just crossed my mind that I might be calculating wrong the front chamber volume. That could be the reason that the frequency responce measurment is much higher then the one simulated by hornresp. What would u calculate as front chamber volume , A or B?
Any thoughts? thx |
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Jake_Fielder
Old Croc Joined: 08 October 2007 Status: Offline Points: 4231 |
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A, the front chamber is All the space from the driver (including inside the cone) to the throat,
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illex
Registered User Joined: 30 January 2008 Location: Greece Status: Offline Points: 50 |
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Yeah , that's what I thought in the first place. But was just wondering maybe i had it wrong cause the real measurment was 20-30hz higher than the simulation. I guess my measurment technique is crap then...
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Jake_Fielder
Old Croc Joined: 08 October 2007 Status: Offline Points: 4231 |
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Not nessicaraly, it just shows that models and actuall results can be quite a bit different!
Horn resp is modeling it as if its a cylindrical rear chamber and a "round" horn,
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