Custom 8x15 bass cabinet

[bootsy666]

[quote name='grenadilla' timestamp='1429100575' post='2747973']
Lovely cabinet! I recommend 4" casters. I got some for a 410 and they are rated at 250lbs. each. (for a cabinet up to 1,000 lbs.)
[/quote]
It has dual wheel casters at 400lbs each.

[alexclaber]

I just quickly modelled your 8x15" cab: From 100Hz downwards it's of pretty much equal sensitivity to our Retro Six10, which can do fairly offensive levels of bass!

It does need bigger ports - at the moment they'll start distorting pretty badly with about 50W. Six 4" ones 6" long will be fine. If you want maximum bass then replace the slanted baffles with one straight baffle for four 15"s and build another box the same size for the other four 15"s. One cab that size with four 15"s will do more bass than the 8x15" - the speakers have room to 'breathe' like that.

[CamdenRob]

[quote name='alexclaber' timestamp='1429101737' post='2747988']
I just quickly modelled your 8x15" cab: From 100Hz downwards it's of pretty much equal sensitivity to our Retro Six10, which can do fairly offensive levels of bass!

It does need bigger ports - at the moment they'll start distorting pretty badly with about 50W. Six 4" ones 6" long will be fine. If you want maximum bass then replace the slanted baffles with one straight baffle for four 15"s and build another box the same size for the other four 15"s. One cab that size with four 15"s will do more bass than the 8x15" - the speakers have room to 'breathe' like that.
[/quote]

That's some free expert advice right there...

Great stuff.

[JamesBass]

Subscribed.

[Bill Fitzmaurice]

To be brutally honest, nothing about that cab configuration is as it should be. It will put out a fair amount of low end, via sheer brute force with a sufficiently large amp, but the same low end output could be realized using two good fifteens in a properly engineered cab. The midrange dispersion will be horrid. My best advice to the OP is that if you haven't bought the TF1525 yet, don't. They're supremely unsuited to electric bass.
Believe me, if I coud find any basis to lend encouragement here I would, but there is none.

[JTUK]

Must admit, I thought this would be a hopeless waste of time, albeit a good fun one, maybe,
but the above advice from BFM puts it into perspective.

Good luck with it tho... and good luck moving it, but as a tool for bass, no, I can't see it, tbh.

[Number6]

Play Primitive Man.....that should suitably destroy the Underworld. I'll just stand by the stairs for a quick getaway 😉

[Matt P]

I've just done a fag packet calculation based on the pictures, and assuming that it's about 4 ft high, 3 ft wide and 20 inches deep, and made from 18mm ply, I'm getting about 40kg for the empty cab, so at least 80kg with the speakers, lighter than the 103.5kg of the basson but compared to a modern 2x15 or one of Alex's 6x10's it's still very heavy. it makes my back ache just thinking about moving it!

Matt

[ras52]

[quote name='bootsy666' timestamp='1429100059' post='2747961']
no mate, I'm in grey widow. This was our backline for our 2014 tour.
Our september 2015 tour will be worse hahaha.
[/quote]

I see that's already enough to blow a drum kit over!

[Balcro]

[quote name='bootsy666' timestamp='1429099844' post='2747956']
It feels quite light without the speakers, my basson cab weighs more.
The drivers are light so it should be too bad, plus my entire band will be helping to shift the thing about.
[/quote]

Bootsy,

I'm with Billfitzmaurice on this one. Wild idea, but when I modelled it in winISD the response curve was unbalanced in the low/mid bass with nearly 4dB lift at 95Hz compared with the level at 230Hz. Despite all the iron employed, low-bass-power- handling was only in the region of 300watts. It looked much more comfortable when set in a closed box of 450 litres!! Only a 1.8dB lift at 125Hz - that would sound very punchy.

The good news is the sound level with 300watts input. How about 139dB between 140 & 160HZ!!!!

Not quite a Saturn V moon rocket, but keep trying.

I suspect the TF1525 is a Bass PA speaker, not really for electric bass.

Balcro.

[bootsy666]

Celestion have told me that the tf1525 is for PA and electric bass.
My other option is the 1530e?

[Bill Fitzmaurice]

[quote name='bootsy666' timestamp='1429121886' post='2748301']
Celestion have told me that the tf1525 is for PA and electric bass.
My other option is the 1530e?
[/quote]You have literally dozens, if not hundreds, of options for drivers. But before you even think about designing your own speaker you have to start with the basics of understanding how speakers work and how they're properly designed. This resource is a good starting place:
http://techtalk.parts-express.com/showthread.php?219617-The-Speaker-Building-Bible

[3below]

Other options (but much more expensive) Eminence 3015 or 3015 LF . Used in earlier generations of Barefaced cabs and in the Fearful range. They also appear in BFM cabinet designs.

[bootsy666]

[quote name='Bill Fitzmaurice' timestamp='1429103627' post='2748022']
To be brutally honest, nothing about that cab configuration is as it should be. It will put out a fair amount of low end, via sheer brute force with a sufficiently large amp, but the same low end output could be realized using two good fifteens in a properly engineered cab. The midrange dispersion will be horrid. My best advice to the OP is that if you haven't bought the TF1525 yet, don't. They're supremely unsuited to electric bass.
Believe me, if I coud find any basis to lend encouragement here I would, but there is none.
[/quote]
What speskers would you recommend?

[bootsy666]

[quote name='Bill Fitzmaurice' timestamp='1429122435' post='2748309']
You have literally dozens, if not hundreds, of options for drivers. But before you even think about designing your own speaker you have to start with the basics of understanding how speakers work and how they're properly designed. This resource is a good starting place:
http://techtalk.parts-express.com/showthread.php?219617-The-Speaker-Building-Bible
[/quote]
Celestion bl15-300x?

[bootsy666]

[quote name='Matt P' timestamp='1429107794' post='2748085']
I've just done a fag packet calculation based on the pictures, and assuming that it's about 4 ft high, 3 ft wide and 20 inches deep, and made from 18mm ply, I'm getting about 40kg for the empty cab, so at least 80kg with the speakers, lighter than the 103.5kg of the basson but compared to a modern 2x15 or one of Alex's 6x10's it's still very heavy. it makes my back ache just thinking about moving it!

Matt
[/quote]
All the ply is inch thick, and the depth is 26"

[HazBeen]

Eminence 3015's would work. Although the maths do not lie, the cab may be pretty well suited for the sludge/stoner I have just enjoyed checking out....

Although a 4x15 straight in the cab you have just built and then another would work better....

Interesting link for you to read.
http://www.markpercy.co.uk/cabinet.htm

[MacDaddy]

Is it weird that although I don't have a clue what Bill and Alex are on about, I still enjoy reading it? [size=4] [/size]

[ras52]

[quote name='MacDaddy' timestamp='1429135141' post='2748496']
Is it weird that although I don't have a clue what Bill and Alex are on about, I still enjoy reading it?
[/quote]

No.

[bootsy666]

I've narrowed it down to these speakers.
Eminence Legend CA154.
Celsetion BL15-300X.
Both manufacturers claim they have been used in slanted cabs with good results, and that they are great speakers for using tunns of fuzz and distortion.
I've used the celestions before in a matamp 4x15 and liked the sound, but I've never heard the eminence before.
Has anyone ever tested them with distortion?

[bootsy666]

[quote name='HazBeen' timestamp='1429132750' post='2748469']
Eminence 3015's would work. Although the maths do not lie, the cab may be pretty well suited for the sludge/stoner I have just enjoyed checking out....

Although a 4x15 straight in the cab you have just built and then another would work better....

Interesting link for you to read.
http://www.markpercy.co.uk/cabinet.htm
[/quote]
That's an interesting read. I did think about boxing the speakers off, but didn't because I needed to keep the weight down.

[VTypeV4]

The 1525 isn't an awesome spec driver (it's quite average to be fair) although I have one in 'normal' sized 1x15 which is tuned to around 45Hz. It works well enough despite a modest 2.5mm Xmax, doesn't seem bottom out at volume and has a pleasing tonal character.

I know the tech says you can probably improve the cab with correct driver loading and using venting to control the response of the low-end and as mentioned, there's certainly better spec drivers but as you've broken all the rules already..

I think this is a full on mad-man project and will be interested to see the finished thing although I never want to be within a couple of hundred yards of it. A potential mid band SPL approaching 140dB!? No thanks! Ha!

[Matt P]

ok, then my calc comes out at about 65kg empty, which would be well over the 103kg of your old cab when you add the drivers, personally I'd be looking at the designs by Bill Fitzmaurice or the fearful designs, 1x15 or 2x15 with the eminence speakers.

Matt

[bootsy666]

[quote name='Matt P' timestamp='1429175504' post='2748712']
ok, then my calc comes out at about 65kg empty, which would be well over the 103kg of your old cab when you add the drivers, personally I'd be looking at the designs by Bill Fitzmaurice or the fearful designs, 1x15 or 2x15 with the eminence speakers.

Matt
[/quote]
The basson weighed nearly 230lbs! I swapped the speakers for green label neo's, it's easier to move now.

[Matt P]

230lbs is 104kg, so I still think the new cab is going to weigh as much as the old one, have you looked at the Fearful 1515/66 ? it's about the same overall size as the cab you are building but will be much lighter and should be much louder.

Matt