New speakers needed in my vintage cab !

[Nostromo]

Hi,

Not sure if this is in the right forum stream ? . . . maybe this should have gone in repairs and technical . . but its very much a "speaker" question and maybe more general knowledge than technical - so here goes :-

I've got a vintage 1970's Hiwatt 2 x 12" cab - minus speakers. As a cab its in very good condition for its age - so good that I'd never get rid of it - and so its been hanging around for ages as a project in waiting.

Its speaker baffle (ie the front board with speaker cloth over) is already cut out for 2 x 12" speakers - so that's obviously what it was previously / originally loaded with. Its 25" wide, 15" deep and 30" tall, very heavily constructed, obviously has plenty of internal volume so would make a good bass cab I should think. Though I would have to say I don't know if it was a bass cab or a guitar cab originally ? It's a closed back design ie not open or ported - just a closed box. There is hardly any legible information left on the data plate on the rear - everything has faded away.

Question is simple . . . Im thinking of running it with a vintage style all valve head (yet to be purchased - but obviously a HIWATT valve bass head comes to mind ? indeed, a HIWATT 400watt valve head would do the trick I think - Ive just been looking at one on eBay !!! . . . . perhaps a silverface bassman might be more in my price range though ??)

So that question . . . yes . . . [b]what replacement speakers should I put into it ?[/b] . . . . .

I'm hoping to recreate a vintage Bass Cab tone and have plenty of power handling ?

Will be running Fenders Jazz and Precision through it - playing Blues and 70's rock.

Any advice much appreciated.

Edited October 25, 2009 by Nostromo

[Mr. Foxen]

I thought infinite baffle was open back, this is a seal cab. Fairly sure no sealed 2x12 will be able to make use of nearly all of 400w. Dunno what speakers though, old or not very expensive ones will probably be a better bet than expensive modern ones that want a ported cab. Or you could put a single modern uber 12 in and use the other hole as a port.

[Nostromo]

Thanks for your thoughts . . . . as for closed baffle/infinite baffle ? . . . you may well be right . . . . !

I'll remove that bit !

[Monz]

As far as I am aware "Infinite Baffle" means the wood that the drivers are attached to is an integral part of the cabinet construction i.e. stressed member

As far as drivers go i have just had another 2x12 made for me by Matamp and chose Eminence Delta Pro 12A and so far they have surpassed my expectations... VERY loud and punchy with great bass response and not mid happy like the neo drivers seem to be, be warned though... they are not light

With regard to valve amps Matamp is the way forward although I would love to own one of the original Hiwatts but then we are back to Matamp again

PS My cab is sealed and will handle 800W (400 per driver)

Edited October 24, 2009 by Monz

[Bill Fitzmaurice]

[quote name='Monz' post='635622' date='Oct 24 2009, 04:09 PM']As far as I am aware "Infinite Baffle" means the wood that the drivers are attached to is an integral part of the cabinet construction i.e. stressed member[/quote]Infinite baffle is where the front and rear waves of the driver are isolated from each other. That may be via use of a 1/2 cubic foot sealed box, it may be by mounting woofers in a wall between two rooms of a house.
The roughly 4.5 cu ft cab of the OP will work well sealed with drivers that have an EBP of less than 75, vented with drivers with an EBP of more than 100, with in between 75 and 100 being OK either way. Delta Pro 12s would require the cab be vented and tuned to 45 Hz. To stay sealed the Beta 12 would work better.

[skankdelvar]

For that old-school vibe, you could look at banging some old Fane speakers in there and topping it off with a suitably modded 100w-ish Sound City.

Not tonally modern - or loud - but oodles cheaper and lighter than a 'vintage' Hiwatt rig. It would probably work just as well as a guitar combo were you to stick a clean boost in front of it

[Monz]

[quote name='Bill Fitzmaurice' post='635702' date='Oct 24 2009, 10:46 PM']Infinite baffle is where the front and rear waves of the driver are isolated from each other. That may be via use of a 1/2 cubic foot sealed box, it may be by mounting woofers in a wall between two rooms of a house.
The roughly 4.5 cu ft cab of the OP will work well sealed with drivers that have an EBP of less than 75, vented with drivers with an EBP of more than 100, with in between 75 and 100 being OK either way. Delta Pro 12s would require the cab be vented and tuned to 45 Hz. To stay sealed the Beta 12 would work better.[/quote]

<applause>

[Nostromo]

Thanx for all the replies to this question so far.

Bill Fitzmaurice's input is useful as I'd not previously understood the importance of the EBP parameter.

Ive just been looking on the RCF website - an enlightened mate down here near Bristol told me they made very good speakers, and, that I wouldn't be able to go wrong if I chose something from their range. Interestingly, they make literally dozens of different model Bass/Mid 12" speakers, many with impressive power handling and efficiency ratings. However, not a single one of them has a EBP of less than 155 and most are in the 200 / 300 range. ie miles away from Bill's recommended range of an EBP of less than 75 ? . . . I therefore conclude that RCF don't make anything suitable for use in a 2 by 12" closed box design ? . . . which is a bit odd as I know RCF make closed box PA speakers and I'd assumed they would use their own drivers in them ? . . . any thoughts Bill ?

Anyway, I will be looking elsewhere as time permits - starting with Monz's advice re Eminence Delta's & skankdelvar's advice re Fane's ! !

Any further advice on best replacement speakers for a vintage 2 x 12" bass cab restoration very very much appreciated.

Edited October 25, 2009 by Nostromo

[pete.young]

[quote name='Monz' post='635622' date='Oct 24 2009, 08:09 PM']With regard to valve amps Matamp is the way forward although I would love to own one of the original Hiwatts but then we are back to Matamp again [/quote]
Monz, would you like to expand on this? As far as I'm aware, there was a connection between Orange and Matamp, but none between Matamp and Dave Reeves or Harry Joyce. Dave Reeves worked for Sound City before he went to Hiwatt. I'm talking about the vintage stuff here, not the 'Hiwatt' made for Music Ground by Matamp in the early part of this decade.

To the OP - you might also want to consider the Celestion 12s, they have a range of neo and non-neo.

[Mr. Foxen]

[quote name='pete.young' post='635986' date='Oct 25 2009, 11:08 AM']Monz, would you like to expand on this? As far as I'm aware, there was a connection between Orange and Matamp, but none between Matamp and Dave Reeves or Harry Joyce. Dave Reeves worked for Sound City before he went to Hiwatt. I'm talking about the vintage stuff here, not the 'Hiwatt' made for Music Ground by Matamp in the early part of this decade.

To the OP - you might also want to consider the Celestion 12s, they have a range of neo and non-neo.[/quote]


Don't mention the Orange connection to Matamp, there appears to be a lot of bitterness there.

[Nostromo]

May be getting warm here . . . . .

The Eminence DELTA-12LFA has a Efficiency Bandwidth Product of 100, the Delta-12A has an EBP of 119 whilst their less powerful BETA-12A-2 model measures up with a EBP of 94 ?

Im beginning to spot a correlation between higher power handling and higher EBP here ? . . . I guess this may be pointing to the fact that for a higher output Bass Cab then venting is the best option ? . . . well, I cant think of any very high power completely closed box modern current Bass Cab designs ? . . but I can think of loads of vented ones !

And it also begs the observation, maybe ? . . . that maybe vintage closed back bass cabs from days gone by, were, whilst big boxes, one the whole, rated at much lower power handling levels than modern cab expectation ? . . . and maybe vintage speakers tended to have a low EBP ?

But Maybe Im wrong ? ? ?

Edited October 25, 2009 by Nostromo

[Bill Fitzmaurice]

[quote]However, not a single one of them has a EBP of less than 155 and most are in the 200 / 300 range . any thoughts Bill ?[/quote]You can use a high EBP driver in a sealed cab, you just won\'t get any bass response from it.
[quote]Im beginning to spot a correlation between higher power handling and higher EBP here[/quote] Pure coincidence. [quote]maybe vintage speakers tended to have a low EBP ?[/quote]Nope. Look at old JBLs and EVs.
The main reason why sealed cabs dominated until the mid 70s was the lack of widespread knowledge of how drivers functioned, and that applied to the people that made them as well as everyone else. That knowledge was quantified by Theile and Small in the mid 1960s, and it took ten years before the electric bass cab industry began to take notice. A good argument can be made that many manufacturers still haven't caught on.

Edited October 25, 2009 by Bill Fitzmaurice

[Nostromo]

Thanks Bill,

Interesting stuff . . . .

I cant help but ask . . . . what speakers would you recommend ?

Cheers,

[Bill Fitzmaurice]

[quote name='Nostromo' post='636193' date='Oct 25 2009, 11:30 AM']Thanks Bill,

Interesting stuff . . . .

I cant help but ask . . . . what speakers would you recommend ?

Cheers,

[/quote]I'd be venting the box for Deltalite II 2512s, or 3012HOs should you ever want to go with more power. Technically the 2512 with an EPB of 84 is sealed cab friendly, but the Beta 12 is less expensive and has a bit better low end sensitivity in a sealed box. The 2512 and Beta 10 are similar in the low end in a vented box, but the 2512 has a better midrange.

[Nostromo]

Thanx for that Bill,

If I went the ported route with higher power speakers in mind, can you offer any advice on how big the port (or ports) would need to be ?

I'm pretty handy and tidy at DIY and have access to a range of tank cutters, so I'm thinking I could introduce a vent, or a series of small tidy circular vents, in the back of the box ?

I can't put any ports in the front baffle board because the grill cloth (in perfect condition) is fixed under glued batons which makes any modifications on the front surface of the box very very difficult without destroying the vintage grill cloth . . Certainly though, if I stick to modifying the back, which is a removable panel, then I will be able to tidy it all up easily.

I've read that these ports or vents needs to be (in area) about a third to a half of the cone area ? . . but . . . . that that port area changes slightly again dependent on the volume of the box and certain characteristics of the speakers fitted ? (Does the EPB come into play here again ?) . . . I'm also unsure as to whether, with a cab containing two 12" drivers, the starting point would be a port area calculation based on the area of one 12 " speaker or whether that calculation would be done based on the area of two 12" speakers ? . . . I would assume the latter . . .but thats just a guess ?

Ive also read that its standard practice to have the ports tubed into the middle of the box, rather than just left as holes on the box surface ? . . - again I could do that easily enough, but, I don't know the science or implications of the length of the tube or tubes ? ?

All in all, its a very interesting subject to think about . . but I just dont know where to start ?

By the way . . though very old, I do have an HND in engineering, so, if i could read up a bit I'm sure I could do the necessary calculations ! . . . . as long as I don't leave it too long that is ! . . . brain cells dwindling away at a hell or a rate these days ! . . ha

I guess its just finding a source of information you can trust - so that the effort put into reading up and working out the specs is repaid in the performance of the cab at the end of the day ?

Obviously when one contemplates drilling holes in a very tidy vintage cab . . then it has to be right first time . . . trial and error is not really an option ! (though I suspect that may be how some of the manufacturers do it !) . ie as much empirically as by calculation ?

thanx again for all the contributions here

Edited October 25, 2009 by Nostromo

[Musky]

I'm reliably informed that [url="http://www.linearteam.dk/default.aspx?pageid=winisd"]WinISD[/url] is quite handy for this sort of thing.

I use a Mac, so I wouldn't know.

[Mr. Foxen]

I reckon make a whole new back with a port is the best plan. Can put the socket somewhere sensible, possibly with a speakon combo socket in it. In fact, instead of holes, make it not quite reach the bottom and put a shelf in, slot port, easy. Length of that shelf to be determined by WinISD.

[Bill Fitzmaurice]

[quote name='Nostromo' post='636272' date='Oct 25 2009, 12:53 PM']Thanx for that Bill,

If I went the ported route with higher power speakers in mind, can you offer any advice on how big the port (or ports) would be[/quote]
45 Hz is a good all-purpose tuning frequency, and 4" ID tubes match well with a 12 inch driver. A pair 5 inches long installed through the back would do. Be sure to line the entire cab with an inch of convoluted foam padding or polyester batting.

[Nostromo]

Noted,

Thanx