Bill Fitzmaurice

Add a four inch duct to the port.

[quote name='Phil Starr' post='857859' date='Jun 4 2010, 07:10 PM']There's a problem with most 4ohm drivers as well. they are usually made by just changing the voice coil for a shorter one which ...reduces excursion (Xmax)[/quote]Not if they do it the right way, by reducing the number of windings on the same former. But your point is valid, not every driver manufacturer does things the right way, and you must pay attention to all the driver specs, not just impedance.

[quote name='cameltoe' post='857651' date='Jun 4 2010, 03:29 PM']So with the RMS output almost doubled from going 8ohm to 4ohm, through a speaker that can handle the power, I'd really see no extra (real world) volume?[/quote]Not enough to make it a worthwhile venture. What would work if you must stay as small as possible is a high powered compact amp, at least 300 watts into 8 ohms, and a fifteen with high sensitivity and long excursion, such as an Eminence 3015. With a low powered amp the only way to get high output is with at least two drivers.

[quote name='cameltoe' post='857309' date='Jun 4 2010, 09:46 AM']However, knowing absolutely nothing about amps, I wondered if it was possible to get the full 150w from my Trace WITHOUT adding a cab? Could I, for instance, swap the 8 ohm driver for the appropriate 4 ohm driver to acheive max volume?[/quote]
Full power is moot; the difference between what you might get with a 4 ohm driver versus 8 ohm is 2dB, and that's best case. Adding a second identical speaker gets you 6dB, which should do the trick.

[quote name='Randy_Marsh' post='849048' date='May 26 2010, 06:54 PM']I'm looking at a Hartke Cab for sale on here. It's rated 150watts RMS at 8ohms and i was wondering if i could increase the power and what it would involve, as i was hoping to get a cab with a bit more kick...[/quote]
Only by replacing the drivers. Just buy a better cab.

They're parallel jacks, either can be used as input or output.

[quote name='Mr. Foxen' post='839089' date='May 16 2010, 01:37 PM']Is this mostly for when you are cramming loads of power into it? I have noticed old cabs have small ports, guessing its because the 2 15s are for sensitivity for lower powered valve amps, and just didn't take those sort of power levels.[/quote]If you go back 20 years or more when drivers with 2mm or less excursion limits were common, limiting them to 20 watts before going non-linear, then yes, you could get away with smaller ports. I wouldn't call 100 watts per driver loads of power, and most B-Ws will take that. If given that much the OP would get chuffing big time.

[quote name='umph' post='839036' date='May 16 2010, 12:33 PM']did you just stick a random port in or did you tune it properly to the drivers? Nice work by the way[/quote]
+1. It may be OK tuning wise, but it's far too small and will chuff at high levels. Two ports with the proper duct length will work much better; minimum recommend diameter with fifteens is 6 inches [i]per driver[/i]. While at it, the cab could use panel to panel bracing fore to aft, side to side and top to bottom. Doing so with even single 1 inch wide braces will quadruple the panel stiffness.

[quote name='OldGit' post='836840' date='May 14 2010, 03:42 AM']Can anyone identify exactly which models they are? Head and Cab.
It just says "Bassman Amp" on the head.[/quote]
[url="http://www.ampwares.com/"]http://www.ampwares.com/[/url]

[quote name='Ancient Mariner' post='834199' date='May 11 2010, 08:32 AM']Resistance and impedance are not the same thing, and what you are measuring is resistance. Impedance varies according to, among other things, the frequency of the signal sent through the speaker.[/quote]
+1.
OP, read this:
[url="http://wiki.basschat.co.uk/info:amps:impedance_and_wattage"]http://wiki.basschat.co.uk/info:amps:impedance_and_wattage[/url]

[quote name='Mr.T' post='828812' date='May 5 2010, 01:55 PM']Does that mean it's Ok for me to think that my new cabs sound good? [/quote]
Some of the fave rigs of all time are Ampeg flip-tops, B12s, B15s, etc. They have one of the worst responses imaginable, with a huge midbass response hump and no real low end. That doesn't mean they don't subjectively sound good.

[quote name='Mr.T' post='828431' date='May 5 2010, 08:46 AM']Would 60 litres be classed as a 'small' cab for a 12" driver?

They are a similar size to the Aggie 12's, and I don't hear too many people complaining about a lack of low-end from those.

But hey....
Horses for courses![/quote]60l is adequate for twelves with Qts of .4 or less. As for the perception of low end response, the human ear is very inaccurate; most people are about an octave low in their estimates of the frequency they're hearing. Low 'B' players who swear they're knocking down walls with 32Hz output are actually hearing the 2nd harmonic at 64Hz. Good thing, as otherwise even a Fridge wouldn't be up to 5 stringer needs.

Eminence has been using Klippel Analysis to measure xmax on their drivers for about four years. It's defined as excursion at 10% THD. It's a far more valid method than coil depth/plate thickness methods, which are neither accurate nor consistent. For instance, in the case of under-hung coils that method gives an xmax of zero.
Comparing the Klippel versus coil/plate figures on Eminence drivers the Klippel figure runs about 15% higher. Using that standard the BN10300S would come in around 2.5mm, and the NTR-10 2520D around 4.9mm.

As to why Klippel is not universally employed it's simply a matter of the manufacturers not buying the gear.

[quote name='JTUK' post='825908' date='May 2 2010, 04:23 PM']Well, crap gear back then was crap gear..we all prorbaly had it at some time.

Got to disagree with the stack influence factor though...
Same rig, different room has had a massive effect on my sound from time to time. That is why I say it is a bigger influence.[/quote]
Room modes are problematic for sure, but one way to minimize their effect is with vertically aligned drivers, which have far more uniformity from room to room, and basically just sound better no matter what room you use them in.

[quote name='JTUK' post='824144' date='Apr 30 2010, 10:25 AM']because most of us would run a mile from having to revert back to the old PA columns for bass. [/quote]In the late '60s I used a Kustom Tuck and Roll 4x12 PA column, it had as much output as a Fridge, with better tone to boot.

[quote]It just looks total cack... and I'd be thinking the variable of the room has far more influence between sounds than how you stack them.[/quote]And that's why no one sells them. How you stack them has more influence over the sound than the room. Your not knowing that isn't the exception, it's the rule, unfortunately.

[quote name='Badass' post='822775' date='Apr 29 2010, 05:17 AM']Anyone else do it the way described by GK?[/quote]
Not me. I set my gain for the desired level of grit, then I set the master for the desired level. It tends to be the other way around with a PA console, where you want it as clean as possible.

[quote name='chris_b' post='821170' date='Apr 27 2010, 04:02 PM']Isn't Bugera and Behringer part of the same company? Nuff said![/quote]
Bugera is the silly quasi-Italian name that Behringer pulled out of thin air to stick on musical instrument amps, so that the ill-informed wouldn't realize it was Behringer until it was too late.

Go either two 2x12 or two 3x10, in both cases with cabs that have the drivers vertically aligned. Use one at smaller gigs, two for the big gigs, and then with the two cabs vertically stacked. The result is far better than either a 4x12 or 6x10, and a much easier haul.

[quote name='muddymesser' post='806720' date='Apr 14 2010, 06:39 PM']hi i'm just starting out and cant afford to buy an amp just yet but i have the leads and adaptors ready for when i do but i was wondering if my bass would work ok if i plugged into my car radio as it has an aux in port on it and is connected to a 400w amp and sub ?



cheers
ben[/quote]Aux inputs are line level; an active bass might work, a passive probably won't. And fitting the car on stage might be a deal breaker.

[quote name='mikeselfinflicted' post='784174' date='Mar 23 2010, 07:35 PM']Thanks you given me alot to think about maybe i could trade them in an find an ashdown ABM 8x10!!!

guitarists get it so much easier its not fair!!!! :snob:[/quote]If loaded with the same drivers it will be but more of the same result.

[quote name='Toasted' post='784125' date='Mar 23 2010, 06:55 PM']I have no idea why anyone would tell you that you need a power conditioner unless they were trying to sell you one.[/quote]+1. The only proponents of power conditioners are those who make them, those who sell them, and those who believe the sales pitches proffered by same. For a more unbiased view ask any amp manufacturer if their amps should be used with one. Not one will say 'yes'.

[quote name='mikeselfinflicted' post='782645' date='Mar 22 2010, 03:40 PM']Hi i'm thinking about changing the speakers in my cabs.

i'm running 2 4x10 ashdown MAG cabs but the speakers just don't seem to cut it, i've been told the voicing of the cabs
is pretty good but the speakers are lame so i was thinking of changing over to eminence BP102's.[/quote]
BP102s will take a lot of power in the low end but they're very weak in the mids; I only use them along with a midrange driver. I believe Ashdown uses Sica OEM drivers and that they aren't of very high quality. With eight of them you don't need a huge power rating, so the Eminence Basslite S2010 should be a good bang for the buck driver and they do sound very good. They also weigh almost nothing.

[quote name='Reissueplayer' post='780438' date='Mar 20 2010, 02:23 AM']I've just bought a TC Staccato and I'm considering their cabs as well. I've seen the cabs stacked vertically and I really like the idea of combining easy transportation, flexibility in placement and the thought of getting both ground contact as well as definition from something closer to the ears.

Is there anyone on the forum that has tried and experienced this? What is the sound dispersion like? How do they compare to a 4x10 cab on the ground? Should I go for two RS210s or combine an RS212 with the RS210?[/quote]
Two RS210s will be subjectively far closer to an 8x10 than a 4x10, only it will have twice the midrange dispersion angle of either. Mixing a 212 and 210 will offer little benefit, if a ten doesn't go low enough for you it will take at the least fifteens, if not eighteens, to make a substantial difference. OTOH twelves vertically aligned have far better midrange than tens horizontally placed, so if you need the power of an 8x10 on occasion get a pair of 212, leave one at home when you don't need that much.

[quote name='Finbar' post='774835' date='Mar 14 2010, 08:36 PM']Okay, on my old QSC power amp, I had a 30/50Hz filter to block out all the extreme lows from reaching my cab and effectively making the cab more efficient.
I'd be interested to see if something to filter out those frequencies would make a difference. I have a small crossover I can try this with to see if the concept works, but where does it actually need to go? If I put it after my pedals but before the amp, would this be enough, or are these frequencies actually generated in the amp itself, even if it isn't fed a signal below 50Hz? If the frequencies are generated in the amp, then how would I go about stopping them reaching my cab?[/quote]
It's not a matter of efficiency, it's a matter of not sending to the speakers frequencies that they can't do anything with, which just muddies up the works, mainly string thump noise. Sub-sonics are not created by the amp. Most bass amps have high-pass filtering built in, so adding another level of filtering might not make much difference. Worth a try, though.

If you've got an 8 ohm 4x10 that's probably 8 ohm drivers wired as series/parallel pairs. Open it up, add another speakon and wire each parallel pair to its own speakon, that's two 4 ohm loads, drive each with one of the Superfly power amps. Pay attention to polarity.