New Light weight Vs Heavy Cabs

[BassBod]

[quote name='Mr. Foxen' timestamp='1378381504' post='2199365']
Abbreviated for you.
[/quote]

It just depends how close you are...think of it as a single headphone for a rock'n'roll lifestyle...I'm currently "rocking it out" learning a covers set for Saturday. Never thought I'd ever have to listen to a White Stripes track, yet alone play it.

[Mr. Foxen]

[quote name='stevie' timestamp='1378318103' post='2198597']
Firstly, you can suspend damping material away from the walls of any cab that has a front-to-back brace. There's nothing unusual in that. Secondly, I find it very difficult to believe that a few extra braces will have any affect on the backwave, never mind make a "huge and under-appreciated difference in tone".
[/quote]

Talking in a bare room vs talking in a room with stuff in it tells you how effective disrupting the inside of an enclosure is. See also the knobbly things on the walls of studios etc. get them in some venues too, bit sculptural. Loads of stuff in pubs gives a nice atmosphere not just because of looking at stuff too. Sort of stuff you'd see if you have much to do with music.

[Phil Starr]

[quote name='redstriper' timestamp='1377859963' post='2192834']
I still don't understand why foam core panels are not used by any commercial cab manufacturers other than Flite.
[/quote]

Using a laminated panel isn't a panacea which cures all ills. Panels transmit sound because of flexure but also because they transmit sound within the structure of the panel. The ideal filler for a composite panel would vary depending upon what job you want it to do. If you wanted great sound damping you would use something like the mineral loaded rubber that is used to deaden sound in car panels. This would make the panels really heavy. Foam makes it lighter but not necessarily better sounding. MDF is actually a really good compromise material with greater density and better internal damping than ply but it isn't resistant to damp and it isn't as tough. In other words the choice of speaker panel is a compromise even where cost isn't an issue.

Cost is always an issue though, no-one is going to buy a £20,000 speaker cab, In practice you could easily pay hundreds of pounds on exotic panel materials and certainly it could add £50 to the cost of the materials. In most cases you would get a bigger improvement in sound by spending that on the speaker itself once you are building well braced conventional cabs.

The final issue is whether you would actually notice the difference. Saving a couple of kilograms on an already lightweight cab might not be worth the extra cost, and you will reach a point where the extra bracing might reduce resonances but they are resonances you never notice anyway.

[BassBod]

Never thought I'd say it..but a cab can be too light. You want them to stay where you put them, even on wobbly stages and you also want them to sit still in transport. My Crazy 8 could easily put on a few pounds, and I think I would prefer a ply built box. The composite just feels a bit too delicate.

Edited September 6, 2013 by BassBod

[redstriper]

The foam core Flite cabs aren't particularly expensive and they are easily the lightest 15" cabs on the market afaik.
I don't remember seeing any bracing inside and they don't feel too delicate, mine have been thrown around a bit and show no signs of damage after years of use.

I don't know the price of foam core panels and there may be some compromise in sound and strength, but I think anyone producing these cabs in the UK would find a ready market due to the incredible weight saving.

[xgsjx]

[quote name='grenadilla' timestamp='1384783549' post='2280623'] I am all for bracing and thick Baltic birch plywood. Poplar is not popular, although I have a Mexican fretless Jazz Bass that has a poplar body. I wonder, is 3/4" the limit? Could two pieces be glued together to make a thick sandwich? An inch and a half would be better, at least for the baffle board.A SVT or Ashdown ABM 610 or 810 have plenty of bracing ( each pair of speakers) . They sound great. [/quote]
Are you planning on using your bass to brace your cab?

[grenadilla]

[quote name='xgsjx' timestamp='1384788487' post='2280703']
Are you planning on using your bass to brace your cab?
[/quote] No-that was a bit of humor. I would let the poplar grow and cut down birch. Fender changed that bass to alder.

[Conan]

[quote name='alexclaber' timestamp='1377775016' post='2191573']

[/quote]

I know that reminded me of something...

[LawrenceH]

Some great discussion here! Best thread on speaker design I've seen in ages.

I agree with others about the limitations of bracing, and the limited utility of pole cross braces. Pole braces are good as an easy fix for limited bandwidth subwoofers and not much else IMO as they only effect certain types of modal vibration. There are some models using FEA that have been discussed online, they have their limitations but they're useful for visualising the different bending modes that contribute to various resonances and making the point that braces themselves must be sufficiently stiff to be useful. See here if interested: [url="http://www.audioholics.com/loudspeaker-design/detailed-look-proper-loudspeaker-cabinet-bracing/finite-element-analysis-part-i"]http://www.audioholics.com/loudspeaker-design/detailed-look-proper-loudspeaker-cabinet-bracing/finite-element-analysis-part-i[/url]

Also it's nice to see the distinction being made between the effects of adding rigidity and damping, and the effect of varying Q regarding the latter (eg uneven panel sizes). I like to see in terms of energy conversion efficiency. With increased rigidity you are increasing the overall energy converted to sound, whereas increased damping is converting more of that energy to heat. I'm not sure where the practical limit sits, but conceptually I favour stiff and as light as possible, to maximise sonic efficiency and reach a point where the resonances are at a high enough frequency that first there is a lot less overall energy to excite them and second damping becomes more effective.

Stevie, I'd be very interested to hear more about your K12-alikes. I'm a big fan of those speakers, on another thread a while back I speculated that the moulded cabs sound decent (IMO) because the Q of the material is lower than eg wood - but that alone won't compensate for the loss of efficiency and so I'd guess that the wood ones sound 'tighter' and measure louder. I've also been building some PA cabs, using 9mm birch ply and quite extensive shelf and column bracing. I hope that these will still be pretty stiff (I couldn't lift them if they were 18mm birch! I want to try birch-faced poplar or similar), will get to the point of testing in a couple of weeks.

[xgsjx]

[quote name='grenadilla' timestamp='1384789657' post='2280723']
No-that was a bit of humor. I would let the poplar grow and cut down birch. Fender changed that bass to alder.
[/quote]
Is alder better for bracing?

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Or would you be better off just playing the bass?

[Guest bassman7755]

[quote name='stevie' timestamp='1377346609' post='2186513']
You can buy an Ashdown 1 x 15 for about £150 on here. Even brand new they're ony £350. What's a Compact - £700?
[/quote]

£150 makes the the ashdown very expensive firewood (which is about all its good for to someone like me compared to a Compact).

Cheapness in and of itself doesn't make something good - the player, band mates and audience arn't going to enjoy the sound of a cab more because its cheap. Same for any gear really, once you payed for it the price is irrelevant.

[stevie]

[quote name='LawrenceH' timestamp='1384805585' post='2280979']

I'm not sure where the practical limit sits, but conceptually I favour stiff and as light as possible, to maximise sonic efficiency and reach a point where the resonances are at a high enough frequency that first there is a lot less overall energy to excite them and second damping becomes more effective.
[/quote]

Looks like someone has resurrected this old thread.

Stiff, light and heavily damped is a valid approach (no doubt you're thinking of the Celestion SL600 here) that certainly works well for mid frequencies. I think that at bass frequencies, the best approach is as much mass as possible, although brick and concrete don't make for very portable cabs.

[quote name='LawrenceH' timestamp='1384805585' post='2280979']

Stevie, I'd be very interested to hear more about your K12-alikes. I'm a big fan of those speakers, on another thread a while back I speculated that the moulded cabs sound decent (IMO) because the Q of the material is lower than eg wood - but that alone won't compensate for the loss of efficiency and so I'd guess that the wood ones sound 'tighter' and measure louder. I've also been building some PA cabs, using 9mm birch ply and quite extensive shelf and column bracing. I hope that these will still be pretty stiff (I couldn't lift them if they were 18mm birch! I want to try birch-faced poplar or similar), will get to the point of testing in a couple of weeks.
[/quote]

I have a pair of Celestion TN1230 12- inch drivers (same as in the K12s) and a pair of CDX1-1731 compression drivers (superior model to the one used in the K12s) on P.Audio Nexo-copy horns. The cab is quite compact - about 20 litres - and is made from half inch ply with three-quarter ply for the baffle. Crossover is 1.6/kHz L/R 4th order.

The Celestion 12s are very impressive. They go to 2kHz before break-up and are ruler-flat in their passband. The whole system measures plus/minus 1db from 200 to 18kHz, something that I don't think was possible even 10 years ago from mid-market speakers. Somebody at Celestion knows what they're doing.

90 percent of the design work is in the crossover and I'm building that now. I expect they'll be done for Christmas.

[RandomBass]

[quote name='stevie' timestamp='1385763130' post='2292089']
Looks like someone has resurrected this old thread.

Stiff, light and heavily damped is a valid approach (no doubt you're thinking of the Celestion SL600 here) that certainly works well for mid frequencies. I think that at bass frequencies, the best approach is as much mass as possible, although brick and concrete don't make for very portable cabs.



I have a pair of Celestion TN1230 12- inch drivers (same as in the K12s) and a pair of CDX1-1731 compression drivers (superior model to the one used in the K12s) on P.Audio Nexo-copy horns. The cab is quite compact - about 20 litres - and is made from half inch ply with three-quarter ply for the baffle. Crossover is 1.6/kHz L/R 4th order.

The Celestion 12s are very impressive. They go to 2kHz before break-up and are ruler-flat in their passband. The whole system measures plus/minus 1db from 200 to 18kHz, something that I don't think was possible even 10 years ago from mid-market speakers. Somebody at Celestion knows what they're doing.

90 percent of the design work is in the crossover and I'm building that now. I expect they'll be done for Christmas.
[/quote]

Stevie, would love to see some pics of your work if you get a chance to post some here. Interesting stuff.

Cheers

Geoff

Edited November 29, 2013 by RandomBass

[stevie]

Geoff, I'm not sure how much interest there is for DIY PA cabs on here - not much I suspect. Unfortunately, I don't have the time to do the kind of reportage with photos that others have done, but I'll post a few measurements when I'm done that might be of interest to one or two people.

[RandomBass]

I'm not interested in a step by step build either - just a pic of the final thing would be interesting, if you do get the chance. No worries if not.

[stevie]

No problem. I'd be happy to do that.

[LawrenceH]

[quote name='stevie' timestamp='1385763130' post='2292089']
I have a pair of Celestion TN1230 12- inch drivers (same as in the K12s) and a pair of CDX1-1731 compression drivers (superior model to the one used in the K12s) on P.Audio Nexo-copy horns. The cab is quite compact - about 20 litres - and is made from half inch ply with three-quarter ply for the baffle. Crossover is 1.6/kHz L/R 4th order.

The Celestion 12s are very impressive. They go to 2kHz before break-up and are ruler-flat in their passband. The whole system measures plus/minus 1db from 200 to 18kHz, something that I don't think was possible even 10 years ago from mid-market speakers. Somebody at Celestion knows what they're doing.
[/quote]
Ahh yes I saw those on sale and after some umming and ahhing decided to buy an 8hm pair, but they'd gone - probably to you! Sadly, Celestion told me they're not planning to release any more for sale to the general public, they just had some excess stock. They looked really interesting as a decent but very lightweight steel basket driver. I thought they'd make a great light 2x12 with the longer voicecoil compared to standard options, or if that didn't work out good PA tops.

[quote name='stevie' timestamp='1385763130' post='2292089']
90 percent of the design work is in the crossover
[/quote]

Indeed, once drivers have been chosen and assuming you're going for standard reflex/sealed then the rest is common-sense to an extent. I'm aiming for something very similar, but using an 18Sound HD1050 mounted on their alu horn. Bit of an unknown quantity to me and not much out there on this compression driver, titanium dome on PEN suspension. Thought I'd take a punt based on suprisingly good experience with their el cheapo xd125 combo, hoping the composite construction means it doesn't have the bad aspects that I've come to associate with many titanium domes!

Hope you get them finished and find the time to bung up a couple of pics/quick report

[stevie]

Looks like I was lucky with the TN1230s then. I got them as 4-ohm versions when Lean were selling them for silly money. I did consider them for bass guitar but that's not really their forte. Your 18Sound compression drivers look really nice, Lawrence, and the 1086 is well regarded. I reckon you'll have a very impressive system when you're finished. What bass/mid did you choose in the end?

[gsgbass]

I went from a heavy cab, to light cab, and back to the monster cab. I'm back to a 76 pound Ampeg HSVT-410HLF cab. For my liking, the big 410 cab is a fuller sound.
[IMG]http://i.imgur.com/jAtbsMA.jpg[/IMG]

[Conan]

[quote name='gsgbass' timestamp='1386379447' post='2299621']
I went from a heavy cab, to light cab, and back to the monster cab.
[/quote]

What was the light cab?

[gsgbass]

The heavy cab was an Ampeg SVT-410HLF Classic Cab (85 pounds). The light was Markbass CMD 121P Combo / Markbass NY 121 Cab (57 pounds total). The Monster is the Ampeg HSVT-410HLF Heritage Cab (76 pounds). I call the HSVT cab the monster, because of the monster sound it has. The HSVT is only 9 pounds lighter than the SVT cab, because of the speakers being lighter. [IMG]http://i.imgur.com/rJjY70p.gif[/IMG]

[geoff90guitar]

Brace, brace, sounds like an airline pilot to me. It's the Neo speakers I can't get on with - they sound like meat and potatoes WITHOUT the veg.

[Bill Fitzmaurice]

[quote name='geoff90guitar' timestamp='1489326528' post='3256031']
It's the Neo speakers I can't get on with - they sound like meat and potatoes WITHOUT the veg.
[/quote][size=8]Zombie Thread![/size]

[size=8][size=4]BTW, the magnet material has nothing to do with the sound created. [/size][/size]

[geoff90guitar]

There got to be a difference.
I said it was my opinion, to my ears. I've tried Celestion replacement Neo 15 in standard cab - crap, MB poor, Vanderkley cabs - disappointed, Ashdown - crap.
However I did try my Trace SMX250 in a BF Gen 3 cab and was knocked out, but, it was indoors and not at a gig.
I'd love to purchase a pair of these, but again if Im disappointed I'd be losing a lot so it would be risky. So, I'm still hanging on to my Trace compact 15 and 2x10 13" deep with back-ache.

[Bill Fitzmaurice]

[quote name='geoff90guitar' timestamp='1489330576' post='3256066']
There got to be a difference.
[/quote]There are differences in drivers. None that cause an alteration in tone or any other audio attribute are related to the magnet material. Just like zombies driver voice coils are brain dead, so they don't know or care what the magnet material is, they simply react to the flux provided, and flux is flux, be the source neodymium, strontium carbonate and iron oxide, AlNico or field coils.