redstriper Posted May 9, 2014 Share Posted May 9, 2014 I have two 15" Flite cabs which I love, they are very lightweight and they sound great, but I believe they are all wrong from a technical standpoint. I play reggae and I like a very deep tone, with no upper mid or treble. I've been told the cabs are too small for the drivers (Eminence Kappalite 3015LF) and the port is too small. They sound great to me but I borrowed an ACME 12" cab and it went much lower than mine do and I wonder if I could get more deep bass extension and possibly more volume level by adding a larger port(s) in a similar way to this post: [url="http://basschat.co.uk/topic/235679-can-i-improve-my-cab-at-all/"]http://basschat.co.u...-my-cab-at-all/[/url] The main problem is, these cabs are made of a composite comprising a foam sandwich between 2 very thin pieces of ply. This makes for a very lightweight cab, but I'm not sure how it will take to being cut with a jig saw. In fact, thinking about it makes me shudder - I don't want to ruin these great cabs. Any advice would be much appreciated. Steve. [attachment=162359:Flite cab.jpg] [attachment=162360:Flite2_amp.jpg] Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted May 9, 2014 Share Posted May 9, 2014 [quote name='redstriper' timestamp='1399676332' post='2446700'] I wonder if I could get more deep bass extension and possibly more volume level by adding a larger port(s) in a similar way to this post: [/quote]Probably not. Deep tone is more than just the cab tuning, it's also the size of the cab. A 3015LF needs at least a 4 cu ft cab, not counting the driver and port volumes, for best results in the lows. Quote Link to comment Share on other sites More sharing options...
redstriper Posted May 9, 2014 Author Share Posted May 9, 2014 Thanks Bill, it's the old compromise between size, efficiency and deep tone. I'm willing to compromise for the sake of size and light weight, they still sound surprisingly good and deep enough for stage monitoring when there's a decent PA. It's actually a relief to not have to take a jig saw to them [size=4] [/size] Quote Link to comment Share on other sites More sharing options...
redstriper Posted May 9, 2014 Author Share Posted May 9, 2014 Another question - Is it likely the drivers will come to any harm by being in the wrong size cabs? Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted May 10, 2014 Share Posted May 10, 2014 [quote name='redstriper' timestamp='1399679909' post='2446733'] Another question -Is it likely the drivers will come to any harm by being in the wrong size cabs? [/quote]Only in that since the cabs are undersized the drivers can't produce what they're capable of, and in the quest for deep lows you might over power them. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted May 10, 2014 Share Posted May 10, 2014 [quote name='redstriper' timestamp='1399676332' post='2446700'] I have two 15" Flite cabs which I love, they are very lightweight and they sound great, but I believe they are all wrong from a technical standpoint. I play reggae and I like a very deep tone, with no upper mid or treble. I've been told the cabs are too small for the drivers (Eminence Kappalite 3015LF) and the port is too small. They sound great to me but I borrowed an ACME 12" cab and it went much lower than mine do and I wonder if I could get more deep bass extension and possibly more volume level by adding a larger port(s) in a similar way to this post: [url="http://basschat.co.uk/topic/235679-can-i-improve-my-cab-at-all/"]http://basschat.co.u...-my-cab-at-all/[/url] The main problem is, these cabs are made of a composite comprising a foam sandwich between 2 very thin pieces of ply. This makes for a very lightweight cab, but I'm not sure how it will take to being cut with a jig saw. In fact, thinking about it makes me shudder - I don't want to ruin these great cabs. Any advice would be much appreciated. Steve. [attachment=162359:Flite cab.jpg] [attachment=162360:Flite2_amp.jpg] [/quote] The reason Stevie suggested an extra port in the other thread is that by swapping the speakers for ones that move a lot more air you risk chuffing noises from a fairly small port. The port area was doubled to let the cab 'breathe' and the ports lengthened to keep the tuning the same. The frequency response then stays the same. You aren't swapping drive units so it isn't relevant to you. Most commercial cabs are sized for practical purposes and are smaller than the optimum size for the deepest bass. It actually improves power handling in most cases. Too big a cab could be a problem but you aren't changing the cab size. Leave the cabs alone. If the sound you want is the 3015LF in a bigger cab then your cabs are worth more than the speaker, so sell them and buy a couple of drivers. You could build a wooden cab of the 4cu ft size Bill mentions and put your speakers in to try if you are really keen to try that sound, or buy a sub. Quote Link to comment Share on other sites More sharing options...
Michael J Posted May 10, 2014 Share Posted May 10, 2014 Are the cabs suitably stuffed? Stuffing can make quite a difference to low end extension by making the box "appear" (to the driver) internally larger than it really is - at the price of some efficiency. Quote Link to comment Share on other sites More sharing options...
stevie Posted May 10, 2014 Share Posted May 10, 2014 Steve, the way to get what you want is to fit a smaller driver - a 12" - which will extend lower at the expense of midrange efficiency. To do that you need a sub-baffle, which you can easily make by cutting a round piece of 1/2" MDF or (proper) ply the same size as your 15". Use the 15 as a template to drill mounting holes in the MDF. Then cut a hole for the 12" driver in the centre of the MDF sub-baffle along with suitable mounting holes. Stick foam tape around the 15" baffle hole in the Flite. Screw the MDF to your Flite baffle, fit the 12" (T-nuts are advisable) and you should be good to go - assuming you've chosen the right 12. The Kappalite 3012LF will probably suit, as well as a number of others. I did something very similar to fit a Kappalite 12LF to an Ashdown Mini 15, which is probably a similar size to your Flite. I used 1" birch because I had enough space behind the grille. If you paint the sub-baffle matt black and fit a standard 12" grille, it should look OK. You are not cutting or gluing your cabinet and the modification is 100% reversible. Quote Link to comment Share on other sites More sharing options...
SubsonicSimpleton Posted May 10, 2014 Share Posted May 10, 2014 Why not buy the plans from Bill for the simplex cab to match your drivers, and make one - no need to risk ruining your existing cabs, and you will be able to A/B properly as you have two drivers (and can perform testing before going to the time and expense of exterior finish & hardware on the new cab). As you already have the most expensive part of the equation(the drivers) in your possession, you don't have a lot to lose. Quote Link to comment Share on other sites More sharing options...
redstriper Posted May 10, 2014 Author Share Posted May 10, 2014 Thanks for the advice fellas . [size=4]I will take my time before doing anything and I may end up doing nothing at all [/size] I haven't noticed any chuffing from the port and I haven't heard any distortion, so I don't think I'm overpowering them. I don't really want to go back to larger cabs like the simplex, because these are so practical, size and weight wise. [color=#282828][font=helvetica, arial, sans-serif]They are suitably stuffed on all inside surfaces, there is no bracing and they sound like congas if you tap them.[/font][/color] [color=#282828][font=helvetica, arial, sans-serif][size=4]But they sound smooth and clear, with no buzzes or distortion - I would just like a bit more depth for reggae gigs with no PA support.[/size][/font][/color] Stevie's suggestion of fitting a [color=#282828][font=helvetica, arial, sans-serif][size=4]Kappalite 3012LF is appealing and the instructions sound simple enough even for me![/size][/font][/color] [color=#282828][font=helvetica, arial, sans-serif][size=4]It would be interesting to hear the difference between the [/size][/font][/color][color=#282828][font=helvetica, arial, sans-serif][size=4] [/size][/font][/color][color=#282828][font=helvetica, arial, sans-serif][size=4] [/size][/font][/color][color=#282828][font=helvetica, arial, sans-serif][size=4]3012LF and 3015LF in identical cabs...... if I can get round to it [/size][/font][/color] Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted May 10, 2014 Share Posted May 10, 2014 (edited) [quote name='Michael J' timestamp='1399707372' post='2446795'] Stuffing can make quite a difference to low end extension by making the box "appear" (to the driver) internally larger than it really is - [/quote]Stuffing a cab lowers the speaker Q, which can tame a midbass peak, but it does not give any additional low end extension. If your cab has boomy response stuffing may help, but if it doesn't go as low as you want that can only be fixed with a larger box. This chart shows response of a driver in a small box with 0.9 Q, the same box stuffed for a 0.7 Q, and a larger box also with 0.7 Q. Lowering the Q of the smaller box with stuffing does not give better lows, but making the box larger does. This chart shows the results with an HT subwoofer, with an electric bass driver the same effect would occur, but about an octave higher. Edited May 10, 2014 by Bill Fitzmaurice Quote Link to comment Share on other sites More sharing options...
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