bumnote Posted November 2, 2009 Share Posted November 2, 2009 I have a soft spot for the old US acoustic amps and i still use a 2x15 cab with one of their 100 w tops. They used to do a monster 4x15 cab with 2 front facing speakers and 2 speakers firing up and gown through a central port? Is this arrangement for a technical/sound reason or is it a way of putting 4 x15 speakers in a more compact !!! form. Photo attached Link to comment Share on other sites More sharing options...
Mr. Foxen Posted November 2, 2009 Share Posted November 2, 2009 Think its same idea as the Schroeder cabs with the sideways speaker. Cuts the highs from one, so you get a bassier balance, cause the speakers were kinda poor. Doubling up surface area, if they were all front facing, would give you more highs than you want. If you put modern speakers in, could probably block up the other hole, and port it. Link to comment Share on other sites More sharing options...
bumnote Posted November 2, 2009 Author Share Posted November 2, 2009 (edited) did you sell your 126? I just picked one up at the weekend, its quite nice, not as nice condition as yours though but i got it cheap Edited November 2, 2009 by bumnote Link to comment Share on other sites More sharing options...
Balcro Posted November 2, 2009 Share Posted November 2, 2009 (edited) That's an Acoustic 408 cabinet. It appears to have a slot port in the upward facing driver baffle. Quite why they were built that way I don't know, but there's probably only one place you'll find out - here: [url="http://unofficialacousticcontrolcorpmessageboard.yuku.com/"]http://unofficialacousticcontrolcorpmessageboard.yuku.com/[/url] Occasionally they have a technical wizard on the forum called Harvey Gerst from the original Acoustic Co. Put an enquiry into the apropriate forum and you should get a reply. Let us all know why they built it like that. You have to be an Acoustic owner to get on the forum. Balcro. Edited November 2, 2009 by Balcro Link to comment Share on other sites More sharing options...
Mr. Foxen Posted November 2, 2009 Share Posted November 2, 2009 [quote name='bumnote' post='643998' date='Nov 2 2009, 11:20 PM']did you sell your 126? I just picked one up at the weekend, its quite nice, not as nice condition as yours though but i got it cheap[/quote] Still got it. For some reason, it agrees best with my EMG loaded BC Rich. Guessing the clanky toppy sound upsets the oldschool speaker less that my mudbuckers. Fairly sure stacking them is pretty Doom. Link to comment Share on other sites More sharing options...
alexclaber Posted November 3, 2009 Share Posted November 3, 2009 I don't think there was a great deal of deeper technical thinking behind that design, like the Tech Soundsystems (and now Schroeder) design it's a way of getting more speakers in a box. The middle pair will be acoustically lowpassed and will also be slightly mass loaded but otherwise it's a normal bass reflex box. I imagine it has similar response in the lows to the Acoustic folded horn 18", the latter due to the lack of horn length, the former due to the lack of enclosure volume per driver, so a big hump in the midbass and not a lot below. LOUD though. Alex Link to comment Share on other sites More sharing options...
bumnote Posted November 3, 2009 Author Share Posted November 3, 2009 Thanks Alex glad I dont have to lift one Link to comment Share on other sites More sharing options...
4-string-thing Posted December 4, 2009 Share Posted December 4, 2009 [quote name='Mr. Foxen' post='643993' date='Nov 2 2009, 11:12 PM']Think its same idea as the Schroeder cabs with the sideways speaker. Cuts the highs from one, so you get a bassier balance, cause the speakers were kinda poor. Doubling up surface area, if they were all front facing, would give you more highs than you want. If you put modern speakers in, could probably block up the other hole, and port it.[/quote] not sure what speaker you have in your 126 to be classed as "kinda poor" but as far as I know, Acoustics came with either Eminence or JBL speakers. Neither of which could be described as anything other than top quality. My 220 head (175 watts) and 402 cab (2x15) are louder (and better sounding) than any modern amp I've tried, including Ampeg and Markbass! Link to comment Share on other sites More sharing options...
Mr. Foxen Posted December 5, 2009 Share Posted December 5, 2009 [quote name='4-string-thing' post='674541' date='Dec 4 2009, 10:08 PM']not sure what speaker you have in your 126 to be classed as "kinda poor" but as far as I know, Acoustics came with either Eminence or JBL speakers. Neither of which could be described as anything other than top quality. My 220 head (175 watts) and 402 cab (2x15) are louder (and better sounding) than any modern amp I've tried, including Ampeg and Markbass![/quote] When I said 'kinda poor' I meant in comparison to modern drivers, seeing as this is the Barefaced thread and all, the Eminence kappalites pull pretty far ahead of trad stuff. I'm fairly frustrated that I can't fault them. Further research has told me its a square magnet Eminence in there. Link to comment Share on other sites More sharing options...
4-string-thing Posted December 5, 2009 Share Posted December 5, 2009 [quote name='Mr. Foxen' post='674847' date='Dec 5 2009, 11:49 AM']When I said 'kinda poor' I meant in comparison to modern drivers, seeing as this is the Barefaced thread and all, the Eminence kappalites pull pretty far ahead of trad stuff. I'm fairly frustrated that I can't fault them. Further research has told me its a square magnet Eminence in there.[/quote] some of those old Acoustic cabs were designed to "throw" the sound further, thus making them seem louder 20 feet away than close up. I'm no expert (clearly) but I suspect this is what they called a "W" design. Again, the Acoustic forum is full of people who know an awful lot more than me... One things for sure, I'd love to know how those old cab designs would sound with modern drivers. Link to comment Share on other sites More sharing options...
Mr. Foxen Posted December 5, 2009 Share Posted December 5, 2009 [quote name='4-string-thing' post='674937' date='Dec 5 2009, 02:02 PM']some of those old Acoustic cabs were designed to "throw" the sound further, thus making them seem louder 20 feet away than close up. I'm no expert (clearly) but I suspect this is what they called a "W" design. Again, the Acoustic forum is full of people who know an awful lot more than me... One things for sure, I'd love to know how those old cab designs would sound with modern drivers.[/quote] I have one of those, discussed here, ripped into the old tech and 'throwing' concept (although it definitely is observable, its not really throwing apparently) [url="http://basschat.co.uk/index.php?showtopic=28973"]here[/url]. I have stuck a Eminence 18 in it, but haven't really tested it since, only in livinging room, which is hardly a suitable venue, as I'm still waiting on getting the amp back. Chunkily built big old cabs with modern drivers in is fairly ideal if you can retune the port to suit. Link to comment Share on other sites More sharing options...
bumnote Posted December 7, 2009 Author Share Posted December 7, 2009 [quote name='Mr. Foxen' post='674847' date='Dec 5 2009, 11:49 AM']Further research has told me its a square magnet Eminence in there.[/quote] both my 406 and the 126 have the square magnet jobbie but I still have an early eminence with the u shaped magnet at the back. The eminence used at the time was probably a fairly standard oem at the time. Link to comment Share on other sites More sharing options...
bumnote Posted December 7, 2009 Author Share Posted December 7, 2009 [quote name='4-string-thing' post='674937' date='Dec 5 2009, 02:02 PM']some of those old Acoustic cabs were designed to "throw" the sound further, thus making them seem louder 20 feet away than close up. I'm no expert (clearly) but I suspect this is what they called a "W" design. Again, the Acoustic forum is full of people who know an awful lot more than me... One things for sure, I'd love to know how those old cab designs would sound with modern drivers.[/quote] a lot of the posters at the acoustic forum have replaced their original speakers with a variety of options. Michael Winter has JBK D140s in his but others have replaced their speakers with everything from fairly cheapo through to peavey black widows nd got good results. I replaced the speakers in the 450/406 I bought in 1977 eventually with very expensive celestions but apart from making the cabinet heavy, gained no real advantage. Link to comment Share on other sites More sharing options...
4-string-thing Posted December 12, 2009 Share Posted December 12, 2009 There is a cab on ebay at the minute which I am sure is a 402 (2x15) It has no blue strip but other than this it looks identical to mine. The drivers have been replaced with Fanes and its rated at 300w. Its in the Leeds area, and I think its the second time its been listed within a week. Might be a bargain for someone? Here's the item number: 230408829503 Link to comment Share on other sites More sharing options...
alexclaber Posted December 12, 2009 Share Posted December 12, 2009 There's a spec which I don't think I've ever mentioned before on this forum, which really nails down the benefit of the Acoustic 4x15". It's this thing called Vd. By doubling the driver count compared to a 2x15" you double the Vd. As amps were getting more powerful in this era but excursion limited power handling wasn't keeping up this solves the problem by halving the enclosure volume per driver and thus reducing sensitivity (and consequently decreasing excursion per volt and thus increasing power handling) in the lows whilst also doubling the ability of the cab to move air (that's that Vd thing again). Fast-forward thirty years and you can get 15" 'full-range' drivers with significantly more Vd than two of the drivers from a 408, so a 2x15" will play louder than ye olde 4x15" - and because you're not doing the twice as many drivers in the same box trick you also get better sensitivity in the lows. Vd, never before did you think you'd want more of those two letters, did you? Alex P.S. That eBay cab looks quite a bargain if you're local! Link to comment Share on other sites More sharing options...
Mr. Foxen Posted December 12, 2009 Share Posted December 12, 2009 [quote name='alexclaber' post='682548' date='Dec 12 2009, 09:17 PM']P.S. That eBay cab looks quite a bargain if you're local![/quote] Comparable internal volume to the Vintage, but the port seems a bit puny for sticking 3015s in it. Tempted, but really no need. Link to comment Share on other sites More sharing options...
Cuz Locust Posted December 17, 2009 Share Posted December 17, 2009 Hi all You do not have to be an Acoustic owner to post over on the [url="http://acoustic.homeunix.net/twiki/bin/view/Acoustic/WebHome"]Unofficial Acoustic Control Corporation website[/url] and forum. You will have to register with Yuku,this is free. Harvey Gerst and others from the Acoustic Control Corporation are seen from time to time on our forum. We welcome you to come and join us any time...The website is ongoing and it has a lot of historical information on the Acoustic amps past and present and things to come. Acoustic Control used Eminence and sometimes CTS speakers as OEM speakers in their front loaded bass cabinets,ex.model [url="http://acoustic.homeunix.net/twiki/bin/view/Acoustic/BassCabinet408"]408[/url], [url="http://acoustic.homeunix.net/twiki/bin/view/Acoustic/BassCabinet406wide"]406[/url],402,[url="http://acoustic.homeunix.net/twiki/bin/view/Acoustic/BassCombo126"]126[/url],136...They used the Aletc Lansings in the model [url="http://acoustic.homeunix.net/twiki/bin/view/Acoustic/GuitarCabinet261"]261 [/url]and the model 201 2x15 guitar cabinet. In the W box Folded horn cabinets,model [url="http://acoustic.homeunix.net/twiki/bin/view/Acoustic/BassAmpCombination361"]361[/url],301 Acoustic used the Cerwin -Vega 18" speaker. Acoustic Control bass cabinets are very efficient cabinets and when they are paired with and Acoustic Control heads they sound incredible and Loud!! I have had an Ampeg SVT ProIV (1200 watts rms)and a Ampeg SVT810E cabinet. I can put this up against my Acoustic 370 (275 watts rms) and my Acoustic model 406 2x15.. The Acoustic is louder and better sounding to my ears... I have a model 126 that I have put a Peavey 1504-4ohm speaker in. The model 126 amp is only rated at 100 watts rms.I use the 126 cabinet with my other Acoustic amps,so I wanted a speaker that would handle more power than the stock Eminence that was available from the late 70's.Eminence is now one of the premier speaker manufacturers in the USA and are making great cast frame and neodymium speakers.I would probably use Eminence if I were replacing speakers now. I also have 2 model 406 2x15s in my collection ( a wide and a narrow version) and I have loaded both with JBL-E140s (Which is what Micheal Winter also uses in his model 408 cabinet). Any chance you get to buy an Acoustic amp on your side of the pond I would for shure jump on it at the 1st opportunity!! BTW there is an [url="http://www.facebook.com/group.php?gid=15949664945&ref=mf"]Acoustic Control Corporation Appreciation Society [/url]on Facebook Have fun and Merry Christmas!! Cuz Locust Link to comment Share on other sites More sharing options...
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