Bill Fitzmaurice

[quote name='redstriper' post='413686' date='Feb 18 2009, 05:31 PM']Why would I try a 2 x 15 when I'm looking for lightweight cabs?[/quote] OK, how many 1x8 or 1x6 w/high pass filtering did you try along with 1x15s w/low pass filtering? When the question posed is whether a top and bottom cab combination have been optimally engineered to acoustically complement each other those options would have to be made available to the consumer. They aren't. The options that are offered are only matched in cosmetics and footprint. Your response is to a different question entirely, that being whether you can run a 2x10 and 1x15 together with an acceptable result. Obviously the answer is yes. Whether it's the best possible sounding option one could only say if you could try the above mentioned 1x8/1x15 or 1x16/1x15 with appropriate crossover, but you can't, so you'll never know. As for Alex's perceived concessions to the conformity game, I'm sure that they will never include a 2x10 to be used with a 1x15, nor a 2x10 with horizontally aligned drivers, nor a 4x10, period. He knows better, and that's more than you can say for the usual sources.

[quote name='redstriper' post='413552' date='Feb 18 2009, 03:03 PM']I tried a lot of cabs and combinations regardless of looks and found the single 15 and 2 x 10 cabs work well together and make a sound that I'm very happy with, although two 15s are my preference.[/quote]How many 2x8 or 2x6 cabs with vertically aligned drivers and high-pass filtering were you able to test matched up with a 2x15 with low pass filtering?

[quote name='Boneless' post='413070' date='Feb 18 2009, 09:06 AM']Maybe from an "audiophile" point of view. A 2x10" cab may not perfectly acoustically pair with a 1x15", but it's a common solution: there must be a reason for it, and the reason is that many people actually like this speaker configuration.[/quote] Your reply is the proof of the proverbial pudding. Cab manufacturers build what sells, what sells is what the consumer thinks 'looks right', and what 'looks right' is what they're used to. Since virtually every manufacturer turns out the same cookies using the same cookie cutter the opportunity for the average player to hear a superior product simply does not exist. And no manufacturer, save a small entity like Alex with his barefacedBass cabs, is going to invest in the R&D and tooling for a superior product that won't sell because it doesn't 'look right', especially when same old same old continues to go out the shop doors.

[quote name='Mr.T' post='413038' date='Feb 18 2009, 08:41 AM']i.e. Trace designed their 1x15 and 2x10 as a set. I assume (some) other manufacturers do likewise.[/quote]Only to the matter of sizing them to the same width for stacking. A 1x15 and 2x10 truly engineered to work together does not and never has existed. Driver displacement and cabinet size requirements increase exponentially as frequency goes down, so while a 1x15/4x10 is a favorite combination the ratio is backwards; a well engineered system would run two to four 15s with one 10. A proper match for one 15 is one eight, or six. 'Matched sets' is a purely cosmetic matter, proper audio engineering is not a consideration.

[quote name='Jamesk86' post='411239' date='Feb 16 2009, 10:55 AM']why? The sub 15 concetrates on more on the lower end of the projection[/quote]-1. The main limiting factor to low frequency output isn't driver size, it's cabinet size. A small 1x15 won't improve low end output in this case. It would be as effective as adding a pair of oars to a motorboat in hopes of going faster.

[quote name='Pookus' post='410410' date='Feb 15 2009, 03:34 PM']My current rig is an Ashdown ABM900 and 8x10 cab. I run the 810 from one of the channels from the ABM900 - which means I have another channel spare. There are two ways I can go 1) drive the sub bass cab from the other channel possibly with a crossover or 2) get a powered sub and take the signal from the sub out. Ideally I don't want to spend much and also am capable of building my own cabs. Please help me make up my mind![/quote] For a sub to have significantly better LF performance than your 8x10 it would have to be twice as large. There's no getting around that fact. OTOH if you do build/buy a true sub you won't need an 8x10 to handle the mids and highs, a 2x10 would be plenty. In short, if you can't get the lows you want from an 8x10 it's time to rethink the entire system from the ground up.

[quote name='Rich' post='407587' date='Feb 12 2009, 08:47 AM']Certainly from personal experience, my rig sounds loads better with two 1x15s than it did with a 1x15 plus a 2x10 -- but YMMV. As the man said, suck it and see![/quote] +1. There are so many variables involved that it's impossible to predict what any particular combination will do. The advantage to using paired identical cabs is that you'll get just what you have now, but a lot more of it. Those with 1x15s who want to add tens to the mix assume that the top end will be better. For a variety of reasons it's just as likely that the opposite will be the result.

The BP102 will likely have a very different response than the Eden, probably much weaker in the mids.

[quote name='casapete' post='404391' date='Feb 9 2009, 10:38 AM']These new cabs look interesting - 1000 watts, 70 lbs etc. Anybody got one - what are they like? (apologies if this thread already posted!)[/quote] They're bass reflex cabs, using the same cabinet technology as every other bass reflex cabinet in existence, loaded with dynamic drivers that use the same technology as every other dynamic driver in existence. That means the difference between them and every other 4x10 of similar size will be slight.

[quote name='Finbar' post='396560' date='Jan 31 2009, 07:07 PM']I find they mess with my distortion sounds horribly, and I find my tone has more balls with it turned off. I just don't like the things.[/quote] Distortion and tweeters don't mix. That's why guitar amps don't have them.

[quote name='EBS_freak' post='396474' date='Jan 31 2009, 04:49 PM']if I have an 8 ohm cab, play, then switch over the cab to 4 ohm without touching any of the controls, the 4 ohm is louder... but thats presumably because the amp is putting more out at those same settings...?[/quote] At average settings, twice the power. Which requires drawing twice the current from the amp, which contributes to additional heating of the amp components. A free lunch there is no such thing as.

[quote name='EBS_freak' post='396477' date='Jan 31 2009, 04:52 PM']I dont like playing without tweeters... given what you've just said, perhaps I just like the artificial sound?[/quote]There is something to be said for having response above 4kHz. The problem lies with the 2kHz to 4kHz octave where neither woofers nor tweeters will go, and it's the lack of that octave that's artificial. A good midrange will deliver better response and dispersion than a woofer can from 1kHz with highs to at least 6kHz, which most will find quite adequate.

[quote name='bass_ferret' post='396293' date='Jan 31 2009, 01:00 PM']Are we paying extra for our cabs for a solution to a problem that does not really exist?[/quote] +1,000. Tweeters are to bass cabs as tits are to bulls. What's required are midrange drivers, which actually give useful response and dispersion that woofers cannot. They're generally not employed because they cost more than tweeters. Tweeters capable of working down to 2kHz are effective, but to make another animal based analogy they are as common as teeth on hens.

[quote name='EBS_freak' post='396071' date='Jan 31 2009, 07:15 AM']The speakers are identical apart from the impedance -[/quote] In that case the difference at small signal will be precisely 3dB, and the difference at full output, assuming the amp is able to drive both to full output, will be precisely 0dB. Again, the only advantage to the 4 ohm is if the amp has the ability to drive the 4 ohm cab to full output and not the 8 ohm, and if your amp can't driver an 8 ohm 2x10 to full output you really need a larger amp, because you've got no dynamic headroom.

[quote name='alexclaber' post='395732' date='Jan 30 2009, 03:57 PM']Here's an interesting question for y'all to consider - what impedance is the cab whose impedance curve is shown below? Alex[/quote] 6 ohms. Nominal impedance is generally considered to be within the range of 1.2 to 1.5 x DCR. DCR usually shows up as the lowest reading on a chart, in this case 4 ohms. The minimum impedance below 100 Hz, which is cabinet derived, makes it look more like an 8 ohm cab, but what the amp cares about is that minimum load area above 100 Hz, and in this case to be safe I'd call it 6 ohms. Of course, Alex's point here is that impedance is neither constant nor obvious. [quote]I've compared EBS 2x10 8 ohms with EBS 2x10 4 ohms. 4 ohm appears considerably louder.[/quote] With otherwise identical drivers the most difference that could exist is 3dB, and then only if the amp used was particularly anemic. If the difference is more than 3dB that would indicate the drivers are different in more than just impedance.

[quote name='alexclaber' post='395601' date='Jan 30 2009, 01:05 PM']I don't believe I've ever insisted that is is always a bad idea. Alex[/quote] +1. It can work reasonably well. The problem with doing so is that the results are totally unpredictable, so if you don't have the opportunity to try before you buy you're taking a big chance on the result. With identical cabs there's no question that they will work together well.

[quote name='fleabag' post='395105' date='Jan 29 2009, 07:56 PM']Does that also work in reverse , Like a 50w/4ohm amp into an 8 ohm speaker would only lose 1.5db, The difference being Still barely audible ?[/quote] At low power where the amp isn't stressed you'll get 3dB, with a halving of impedance, though 3dB isn't all that much either. But at full power there's not a lot of advantage, so if your amp is inadequate into an 8 ohm load it will likely be inadequate into a 4 ohm load. Conversely if you have plenty of output into 4 ohms you'll have plenty in to 8 as well. All things considered 8 ohm cabs are better because if you ever need to use two you can.

[quote name='ironside1966' post='394571' date='Jan 29 2009, 09:10 AM']As a rough guide most amps rate there power at 4 ohms, a 100w amp will deliver 100w into 4 ohms. 50w into 8 ohms. 25w into 16ohms[/quote] With SS amps output current delivery versus impedance load at full power isn't linear. A 50w/8 ohm amp can be expected to deliver 70 watts into 4 ohms, 35 watts into 16 ohms. As for the notion of running as low a load as possible to 'get all the watts out of my amp', in most cases that's not a good idea. Most cabs can't make use of more than half their rated power before the drivers run out of excursion, and running any amp at minimum load impedance significantly raises the amount of heat generated in the amp, significantly lessening component life. As in all things, moderation.

[quote name='alexclaber' post='391552' date='Jan 26 2009, 06:31 AM']Bear in mind the dustcap output of many 12"s goes higher than that.[/quote] Measure any twelve and you'll find the off-axis response starts drops around 1kHz. Where the dome output is concerned there's a transition zone between where the output of the cone starts to roll off and that of the dome kicks in, giving a hole in the off-axis. This doesn't show up in an on-axis plot. Using a mid at 1kHz-1.2kHz fills that hole. [quote]there are a surprising number that like the scooped out off-axis response of a woofer plus tweeter cab. Also, if you're going without a tweeter you may find many players that want to keep the on-axis clarity for themselves and just let the midrange punch and lowdown fatness be what the band and audience hears. Horses for courses.[/quote] IMO it's not so much a matter of preference as it is not ever having played through a cab with either flat response or uniform dispersion. One tends not to miss what one has never experienced.

[quote name='bremen' post='391096' date='Jan 25 2009, 12:59 PM']I understand that Vd is the volume of air the speaker can move, but why does this matter if the Winisd model shows such close frequency response, power handling and efficiency betwen the two drivers?[/quote] Look at the maximum power and maximum SPL charts and you'll see why.

[quote name='bremen' post='389950' date='Jan 23 2009, 03:04 PM']It's incredible isn't it (on paper at least). It's almost exactly the same response and power handling as the 3015LF, just a couple of dB quieter, in a box literally half the size. 110dB of bottom B from a 50 litre box![/quote] Don't get too carried away, the 3012LF Vd is 496cc, compared to 846cc for the 3015LF, so the price/performance award still goes to the 15. I'm recommending the 3012LF only when the cab size requirement is too small for the 3015LF to fit.

[quote name='bremen' post='389750' date='Jan 23 2009, 11:21 AM'][url="http://www.eminence.com/pdf/kappalite-3012lf.pdf"]http://www.eminence.com/pdf/kappalite-3012lf.pdf[/url] Modelled this in WinISD and it looks like it can make 114dB down to 40Hz in a 50 litre box! What do you think, Alex? Bill? I've emailed Eminence UK to see if they'll sell me one. Bluearan and Thomann don't list them yet.[/quote] I've had both the 3012LF and HO and a couple of OEM versions for about 6 months. They've been added to my plans where applicable. IMO the best twelves made. [quote]but like the 3015LF it'll need a midrange driver for the vast majority of players[/quote] Assuming one desires useful off-axis response above 1.2kHz or so every twelve does.

[quote name='sifi2112' post='389240' date='Jan 23 2009, 01:49 AM']Thanks for all the advice .. but just how does Bergantino do it with his NV series ?[/quote] Eminence OEM special makeup drivers that you can't get unless you open a factory and buy them in minimum lots of 50. If there was sufficient demand for a similar product at retail Eminence would offer it, but there isn't, so they don't.

[quote name='RIM Basses' post='389020' date='Jan 22 2009, 04:06 PM'][url="http://cgi.ebay.co.uk/Eminence-Beta-12-250W-12-Mid-Bass-Driver-8-ohm_W0QQitemZ140292857505QQcmdZViewItemQQptZUK_ConElec_SpeakersPASystems_RL?hash=item140292857505&_trksid=p3286.c0.m14&_trkparms=72%3A1301%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318"]http://cgi.ebay.co.uk/Eminence-Beta-12-250...A1%7C240%3A1318[/url] Any good alex?[/quote] Not gosh awful, but not great. You need to be looking at driver spec sheets for an EBP rating of between 50 and 75 for best results. This happens to generally equate with cheaper drivers that more than likely will have other performance issues and limitations. The demand for high quality drivers for sealed cabs is zilch, ergo there are very few to be found.

[quote name='Mr. Foxen' post='381501' date='Jan 15 2009, 12:02 PM']It's a clone af the Acoustic 36x: much like: Jaco got plenty of mid in his sound, something special about those?[/quote] That's a variation of the 1970s JBL Keele W bin, which is described by inventor Don Keele as [i][b]A medium-throw "W” folded horn providing uniform response from 55 Hz to 400 Hz [/b][/i]Just like a modern subwoofer It never should have been used alone, but should have been be paired with a 1x10 atop it. Jaco's tone was mainly the product of his fretless, and he boosted his treble to full and pulled the bass EQ down to make the best of the response shortcomings of his Acoustics.