Bill Fitzmaurice

[quote name='yorks5stringer' timestamp='1438152174' post='2832015']thought maybe with the Tweeter Box connected I'd get the full 60 watts
[/quote]Adding a tweeter will give more output, but only in the highs, where the tweeter operates. As for the effect of going from 45 to 60 watts, it would be inaudible anyway.

[quote name='Dan Dare' timestamp='1437667212' post='2828060']
Good point, Bill. Despite the established consensus that one should drive preamps as hard as possible for best signal to noise, I find I get a cleaner sound out of my bass head (EBS 350) by running the output gain high and keeping the preamp gain well down so that the clip light never illuminates. I run my mixing desk channels well below the red, too. I think the advice originates from the time when circuitry was far noisier than it is today - you had to keep the hottest possible signal to mask that noise. As you say, passing an already clipped signal to a hefty power amp is asking to destroy your drive units.
[/quote]Actually the advice dates to the early days of pro-sound when 100 watts was a huge amp, and instead of using enough of them to do the job sound providers did clip the power amps, resulting in this from JBL:
http://www.jblpro.com/pub/technote/lowpower.pdf

[quote name='tauzero' timestamp='1437589404' post='2827389']
[url="http://sound.westhost.com/tweeters.htm"]http://sound.westhost.com/tweeters.htm[/url] - why tweeters blow, plus interesting bits on the trend to heavy compression in the recording industry and why using a bigger amp isn't the answer.
[/quote]Most of that is correct, but it doesn't really apply to bass amps, and only partly with respect to PA. That's because bass amps and PA systems routinely pass clipped signals, some created in the power amps, but most created much earlier in the signal chain. Those clipped signals result in abnormally high THD, and that does kill tweeters. It's true that a larger power amp usually won't make any difference, because more often than not the clipping takes place in the pre-amp or in the mixing console.

I went from a digital board and separate amps to a powered mixer, this one (RX 1200L), as it does everything I need it to when mixing on stage:
http://carvinaudio.com/collections/rx-series-mixers
A separate board does offer more utility, but if you don't have a soundman running it you probably won't be able to make full use of it.

[quote name='MoJo' timestamp='1437245646' post='2824674']
Volts are volts, right?
[/quote]Right. That doesn't mean that some Class D amps might not be anemic, but don't blame it on being Class D, blame it on poor design by the manufacturer. Powersoft wouldn't be where it is if there was something inherently deficient about Class D.

Go to music stores, try various cabs, buy the one that has the tone you like the best. If you need more volume than one will give, buy two, stack them vertically.

[quote name='Mudpup' timestamp='1436396245' post='2817909']
Looks like he's back in business soon
[/quote]Only because Fender sold G-B. He would have signed a non-compete clause that kept him out of the business for at least five years when he sold out to Fender, but as that agreement would have been terminated when Fender sold G-B.

[quote name='bonzodog' timestamp='1436362564' post='2817508']
Well I have learnt something today then
As its happens since we bought a better mixer with XLR outputs we use mic leads leads now anyway but with our old mixer with only jack outs w3 used speaker leads!
[/quote]They will work, electrons aren't picky, but since speaker cables aren't shielded they're prone to low frequency hum and high frequency noise. It's usually not severe with a low impedance line level signal. Use a speaker cable to connect a high impedance passive pickup bass to your amp and the hum and noise will likely be intolerable.

[quote]Thanks for your advice, I'm going to do it anyway. [/quote]Then why did you bother asking the question?

[quote name='bonzodog' timestamp='1436359678' post='2817460']
But then why out of the same mixer you use speaker cables to go into active speakers when its the same principal???
[/quote]You don't.

[quote name='landwomble' timestamp='1436356448' post='2817393']
Don't do it. Fire risk.
[/quote]Fire, and a blown amp too. Those are worst case of course, but it can happen. Speaker cables are made to handle high current, instrument cables are not.

[quote name='Merton' timestamp='1436100807' post='2814910']
Methinks HJ was being silly
[/quote]Could be, but far too many think that there's a difference. Were that not the case the terms 'SS watts' and 'valve watts' wouldn't exist. Not would 'TC watts'.

[quote name='TRBboy' timestamp='1436087450' post='2814770']
I would love to have something which sounds at least as good as my 2X12" but is a 'one-hand carry'..[/quote]Simple task, use two tens or one twelve with as much driver displacement as your 2x12. [quote]Maybe I should find a custom cab design company, and send them some sketches?
[/quote]It won't come cheap. My fee for a one-off design is $2,000 USD. That's because the average time required to come up with a fully functional design is at least 80 hours. That's not an issue for a company that expects to sell hundreds, if not thousands of cabs. The only way I manage to sell my plans for $15 is that their sales also number in the thousands.

[quote name='Happy Jack' timestamp='1436002290' post='2814246']
So are these solid state watts or valve watts then?
[/quote]Really? James would do a face palm if only he could.


A watt is a watt, no matter what the source. The difference between SS and valve is that valve has a natural compression, easing the transition into clipping, making them subjectively able to apparently go louder at the same power level before things sound nasty. Using the right compression alogorithm with SS can duplicate the effect. TC does just that, and in the process they attempted to re-define the watt. That probably sent James into doing cartwheels in his grave.

[quote name='TRBboy' timestamp='1436049247' post='2814636']
if it was as simple as working out the calculations for the optimum bass cab, surely there would be only one design which was 'the best'?
[/quote]True, which is why it's not that simple. Every speaker is a compromise. Knowing where you can compromise and where you shouldn't is something that one only learns through experience. For every diamond I've designed there were at least four lumps of coal, which like all lumps of coal ended up as ashes.

Odd how often this subject comes up. My car has a top speed of 130mph, yet the speed limit is only 75. How does one deal with that issue? [i]Don't put the pedal to the metal. [/i]Seems obvious to me.

BTW, clipping can toast tweeters, but has absolutely no effect on woofers. Sometimes even those who really should know better don't.

[quote name='Skybone' timestamp='1435531053' post='2809837']
if a 4 x 10 cab has an 8 ohm rating (ie, 4 x 8 ohm speakers), would it be possible to rewire it so that it would become a 4 ohm cab, without changing the speakers?
[/quote]As explained above, no. And if the reason is the usual 'to get all the watts out of my amp', it wouldn't matter anyway.

[quote name='Dan Dare' timestamp='1434827917' post='2803182']
Don't worry about wattage, etc. Speakers can handle much higher than stated ratings in short bursts. [/quote]With a few exceptions thay cannot handle even half their rated power before they'll distort, so if you don't push them so hard they they are distorting you'll be nowhere near their power capacity. That's where the volume control comes into play
[quote]You're more likely to cause damage by under-driving a cab.[/quote]That would be fostering the myth of underpowering. There's a reason why it's a myth.

I ran a 3500 for ten years, never any problem, always sounded good. I only sold it because it weighed a ton. Or is it tonne?

[quote name='ubit' timestamp='1434460037' post='2799777']
I find when we play, I hear everything clear as hell. As the night goes on, even though nothing is changed, I find everything becomes a wall of noise and I struggle to hear myself or the other instruments clearly. I realise our ears start to filter out certain frequencies and it's probably down to us being too loud at the back line.
[/quote]+1. Your ears will lose sensitivity as a protective reflex when exposed to constant high sound levels. This is why you seem to be softer at the end of a set, and why when you take a break and then go on again it seems louder than just before the break, as during the break hearing sensitivity is restored. One way to address the apparent loss in volume with time is to play louder, which only makes things worse. The smarter route is to either play at lower volume or use earplugs. Better that than eventually needing to use hearing aids.

[quote name='Jenny_Innie' timestamp='1434450680' post='2799621']
I went from kickass bad girl growl to dull beardy geography teacher in corduroys mush. Not very punk.
[/quote]Growl can come from two sources. One is pushing the amp into clipping, the other is pushing the speaker into clipping. If the amp and/or the speaker has a lot of available headroom then you might not be able to get growl without being too loud for a given room. You might be able to get what you want by turning down the amp master, or by running only one cab, or by using a pedal or rack device. You also may find that Barefaced isn't the best cab for you, as they tend to have a lot of headroom.
If you do decide to downsize a small valve amp, 35 to 50 watts, may give you what you're after.

[quote name='xgsjx' timestamp='1433257114' post='2789478']
Why 2 different cabs?
[/quote]Probably because he thinks that the 1x15 will give better lows and the 2x10 better highs. Sometimes that's true, but only sometimes, and even if there's a difference it's usually slight. I'd do two vertically stacked 2x10s myself.

Based on your description I wouldn't be concerned unless the winter temperatures in the shed regularly go below freezing. That in itself isn't an issue, it's the condensation that will form when you return the gear to a warm space that will.

[quote name='Iain' timestamp='1432816905' post='2785245']
Is this a useful rule for front-ported cabs as well or more so for rear-ports?
[/quote]The port location doesn't matter. The boom frequencies tend to be centered in the 100-160Hz range, port output tends to be centered around 50-60Hz. From the standpoint of boundary loading off the wall that requires the source be less than 1/4 wavelength distant. 1/4 wavelength at 60Hz is 4.7 feet. Wnen it's exactly 1/4 wavelength theres a cancellation notch. For instance, having the cab front 2.3 feet from the rear wall would notch the response around 120Hz, while below that would be unaffected, be it front or rear ported.

[quote name='Beer of the Bass' timestamp='1432737942' post='2784430']
I've played around with boundary reinforcement when playing unamplified double bass - I've found that standing as far into the corner of the room as possible seems to give me a little extra low end.
[/quote]A wavelength is a wavelength, no matter what the source.

[quote name='FuNkShUi' timestamp='1432733001' post='2784362']
I am guessing having the sound closer to ear level is a good thing, but having it off the floor, does that effect its perceived sound?
Do i lose anything by doing this?
There was a thread a little while back where someone posted a picture of their cab which was perched on what looked like a keyboard stand (cant remember exact thread sorry). That's what got me thinking.....
I have a 2X10 setup now, and wondered if this kind of thing would benefit or hinder me?
[/quote]You'll start losing floor coupling at about 2.5 feet off the floor, so don't go higher than that. If it's still hard to hear tilt it back. A keyboard stand is a bit too high.
The same applies to the distance to the wall behind the cab. Placing the front of the cab more than 2 feet from the wall will not only reduce boundary reinforcement off the wall, it will cause a response dip. That can be of use on boomy stages. The correct distance from the wall can put the dip at the boom frequency, cancelling out the boom.