Custom 8x15 bass cabinet

[bootsy666]

I've built a custom 8x15 bass cab over the last 2 weeks. I'm very happy with it, but I'd like some advice on venting. it has six 2" holes in the front, anyone think I should add a few more?
The speakers that I've ordered are celestion TF1525.

[Wooks79]

Saw this on facebook. Want one

[Number6]

Have you got your own forklift?

Very nice btw

[planer]

Holy Moly Batman, that's a cab.

It won't be flapping your trousers - they'll be off down the street on their own!

[bumnote]

Chi Mike will want one

[bootsy666]

I'm looking forward to testing it next week.

[spyder]

Crazy

[bumnote]

If only i was 50 years younger, what a beast. I always thought the Acoustic 408 was a monster but this is something else. f*** me or words to that effect

[3below]

I am lost for words. I did the Acoustic 370 and Marshall 4 x 15 thing in my youth. An 8 x 15 makes me think of Robert Oppenheimer who remarked after the first A bomb that it brought to mind words from the Bhagavad Gita: "Now I am become Death, the destroyer of worlds.". The vents seem a bit small (compared to my puny weakling Barefaced Dubster 2 x 15 - small upstart wimpy cab )

Just noted where you live - luckily I am at a safe distance when you undertake tests.

An excellent undertaking

Edited April 13, 2015 by 3below

[Jenny_Innie]

Is you the bassist for Disaster Area?

[JapanAxe]

[quote name='bumnote' timestamp='1428958421' post='2746498']
Chi Mike will want [s]one[/s] two
[/quote]

Fixed.

[Billy Apple]

I'd be interested to know how much more air this will shift as opposed to an 810? I thought the magic was all in the voice coil and xmax excursion, which could be just as big for a 10" with the extra inches in a 15 being the paper cone?

[Dad3353]

I'll wait for the 8 x 18" build topic.



No, seriously, that's a mammoth project. Can we have a video of the first tests in earnest..? It's been a long time since I saw someone literally blown away..!

[planer]

[quote name='3below' timestamp='1428959275' post='2746511']
Just noted where you live - luckily I am at a safe distance when you undertake tests.
[/quote]

Uh-oh, I'm not! I work in Shoreham.

Bye everyone, it's been fun...

[3below]

[quote name='Billy Apple' timestamp='1428961407' post='2746544']
I'd be interested to know how much more air this will shift as opposed to an 810? I thought the magic was all in the voice coil and xmax excursion, which could be just as big for a 10" with the extra inches in a 15 being the paper cone?
[/quote]


A well made point about speaker volume displacement and excursion. We now need the technical input of Mr Claber and Mr Fitzmaurice - what would the optimal 8 x 15 look like? Single column of 15s or cross fired blocks of 4. How could it perform?

[bootsy666]

[quote name='3below' timestamp='1428962000' post='2746550']



A well made point about speaker volume displacement and excursion. We now need the technical input of Mr Claber and Mr Fitzmaurice - what would the optimal 8 x 15 look like? Single column of 15s or cross fired blocks of 4. How could it perform?
[/quote]


These are some answers I'm looking for before I test it with the speakers in.

Edited April 13, 2015 by bootsy666

[bootsy666]

Celestion have told me that the these speakers need some venting for heat, but they couldn't say how much because they have never seen an 8x15 before.

[gjones]

That's going to trigger a tsunami in Shoreham by Sea.

[bootsy666]

[quote name='gjones' timestamp='1428966288' post='2746613']
That's going to trigger a tsunami in Shoreham by Sea.
[/quote]
I don't think I'll ever use here haha. My first gig with it will be the Camden underworld in June, I may have to give them some notice first.

[Number6]

[quote name='bootsy666' timestamp='1428966856' post='2746621']

I don't think I'll ever use here haha. My first gig with it will be the Camden underworld in June, I may have to give them some notice first.
[/quote]

Right Underworld in June.....i'm there!

[CamdenRob]

[quote name='bootsy666' timestamp='1428966856' post='2746621']
My first gig with it will be the Camden underworld in June
[/quote]

You'll have to get down and (more importantly) back up the stairs with it at the underworld....

Edited April 14, 2015 by CamdenRob

[Dad3353]

[quote name='CamdenRob' timestamp='1429025416' post='2747162']
You'll have to get down and (more importantly) back up the stairs with it at the underworld....
[/quote]

Why..? Won't they hear it from his home..?

[CamdenRob]

[quote name='Dad3353' timestamp='1429025594' post='2747164']
Why..? Won't they hear it from his home..?
[/quote]

I'll certainly be able to hear it in my home if he playes the underworld with that thing...

[Beer of the Bass]

Have you used a modelling program like WinISD to figure out the size and shape of the ports in the front? That should be your first port of call when trying to work the area and length of ports to use - they're not just vents to reduce heat.
I wonder how much heat the drivers will actually produce - If that's a VBA400 in the picture, each driver would only be handling 50 watts at full output, so perhaps heat won't be such a big issue.

[3below]

[quote name='Beer of the Bass' timestamp='1429030342' post='2747218']
Have you used a modelling program like WinISD to figure out the size and shape of the ports in the front? That should be your first port of call when trying to work the area and length of ports to use - they're not just vents to reduce heat.
I wonder how much heat the drivers will actually produce - If that's a VBA400 in the picture, each driver would only be handling 50 watts at full output, so perhaps heat won't be such a big issue.
[/quote]

Good advice and sharp observation on the VBA 400 and the power sharing. A rough estimate based on my Dubster suggests an 8x15 would need 1670 cm^2 of port area. This is a very rough estimate, WinISD or similar as suggested is the way forward if you want a correctly vented cabinet.

Edited April 14, 2015 by 3below