Bill Fitzmaurice

There are no output capacitors in your amp. You may increase the value of the power supply filter caps for somewhat lower ripple and better headroom, but the difference won't be major. It might not be even noticeable. Changing the wire will have no effect, it's far too short. Of all the shortcomings of an inexpensive combo amp the filter caps and speaker wiring are among the least significant.

[quote name='discreet' timestamp='1397229356' post='2422047'] The second cab build was painted with black TuffCab using a textured roller and I'd recommend this over vinyl any day. If it gets scuffed you can just touch it up again [/quote]+1.

[quote name='EddyGlee' timestamp='139626938] I could have probably found and posted Reggae bassists who use 410/115 stacks who have lows that make your eyes go blurred [/quote] I could go one better and post an RTA of 'The Wailers' in concert. The bass rig was an SVT, not that it matters, because you didn't hear the amp, you heard the PA. In this case it was a no-holds-barred million dollar plus system. The RTA shows uniform content from 50-125Hz, dropping below and above that. The level in that band width at the FOH where I took the RTA, 100 feet from the stage, averaged 106dB. It was that level that gave the impact, not the frequency. To the untrained ear, or even the trained one without a meter in hand, the assumption could have been made that most of the content was between 30 and 50Hz, but in reality it was an octave higher.

[quote name='dmccombe7' timestamp='1396129338' post='2410316'] Surely if you direct more of the low end frequencies to the 15 and high end to 10's it should provide a cleaner sound overall. [/quote]It would if there was a significant difference in their response, There isn't. And using one 15 with four tens makes as much sense as building a pyramid...with the pointed end down.

[quote name='dmccombe7' timestamp='1396086788' post='2409751'] Historically I always bi-amped into 2 cabs to give me that low end and clear mids to high and with the Ampeg you have that built into one amp. [/quote]That's a valid approach with cabs that are quite different in their responses, being specifically designed to operate well only in the lows and only in the mids and highs. Ampeg cabs are not. Ampegs may have slight differences in response, but only slight, for all intents and purposes they're all full range cabs. That pretty much applies to all electric bass cabs. To find true sub/tops you have go to the PA cab suppliers. As for a 1x15/4x10 in particular, it simply makes no sense. You don't need fewer drivers when you go to lower frequencies, you need more, A 2x15/2x10 would be a logical pairing, the 2x15 being a PA sub flat to 30Hz, the 2x10 being a top that doesn't work at all below 80Hz but functions well to 4kHz.

[quote name='spinynorman' timestamp='1396096572' post='2409900'] The mics are SM58s, would changing the mic help?[/quote]Yes, A sound reinforcement forum can point you in the right direction.

[quote name='MoJo' timestamp='1395993413' post='2408649'] The combo is 4 ohms (two 8 ohm drivers wired in parallel) with a single extension output socket, minimum load 4 ohms [/quote]You want a 4x10 that's half the impedance of the 2x10. Obviously that's not an option, so a 4 ohm 2x10 is your best bet. But that still gives you four tens total, and the difference between that and six tens isn't all that much.

[quote name='Si600' timestamp='1395995324' post='2408677'] If you have to, then why aren't we all using little combo's and letting the PA do the heavy work? [/quote]You should be. Maybe not little combos, but if you have a good PA then all you need for backline is a rig large enough for on-stage monitoring. But few bands have a good PA [quote]Small venues are ok for just back line with maybe vocals through the PA, but for larger venues , you will definitely be looking at mic'ing up or DI'ing [/quote]I always mic the drums and guitars even in the smallest of venues, because that's the only way to get even midrange and high frequency distribution thoughout the audience. My bass is the one instrument that I'll leave out, as lows don't need to be in the PA for sidpersion, and my 1x12 is adequate to push even 200 seats without assistance. If I do put the bass in the PA in smallish rooms to spread my highs I high pass that channel at 160Hz.

[quote name='Diablo' timestamp='1395822943' post='2406619'] Me vs two guitarists and 1 drummer has not been a fair competition so far, so for the gig this Friday I'm going armed [/quote]You're probably still under-gunned. Look at the diameter of your low E string. Compare it to that of a guitar low E string. For the very same reason that your low E string is fully twice the diameter, and therefore four times the cross sectional area, of the guitar string your speakers need to have that same size relationship compared to what the guitar player has in order to play as loud.

[quote name='Diablo' timestamp='1395702213' post='2405404'] I realise you will end up with different voltages, but is it not the power that matters given a bit if V=IR and P=I squared R? [/quote]What matters is that all the drivers receive the same power, and that's assuming they're identical. If they're not identical the possible permutations are considerable, and most of them aren't good. A favorite combination is a 1x15/4x10, but if each ten is receiving the same power as that one fifteen it's a bad news situation. Bottom line, the best option is to use identical speakers, that way you won't get into trouble.

[quote name='Balcro' timestamp='1395531423' post='2403516'] I'm running winISD Pro Alpha v 0.50a7 and I get an identical result. Quite why Eminence recommend, an enclosure volume between 51 & 119 litres I don't know, but they do. I only found 1 version download on the Linearteam web-site, but I'll try it on my other computer with W7. [/quote]I don't have the Eminence software, so I can't run it to see what it does. I know that Eminence tends to recommend a smaller box size, IMO probably for marketing reasons. The W7 version isn't on the Linear Team site, it's at https://www.facebook.com/WinISD/posts/126113234166443?stream_ref=10

[quote name='Balcro' timestamp='1395512274' post='2403279'] Hi Bill, I understand the option, but I advised on an inside mounting as the volume taken up by the port has already been accounted for in the enclosure net volume calculation of 123.6 litres and Eminence's recommendation is for 119 litres. Still, it's only a gain of 1.2 litres, so won't make a great difference. Putting it on the outside may well be practically & cosmetically easier with no chance of damaging the port tube. At 119L with the same tuning you lose 2dB from 40 to 50Hz, and that's right where I don't want to lose anything. As for XP, support for it ends in three weeks. Now is a good time to jump to W7, as any computers still on the shelf still loaded with it are on sale. Thanks for the tip about the Windows 7 version. I'll look it up. It's a couple of months since visiting Linearteam, being an XP luddite. [/quote]My WinISD defaults to a QB3 alignment for the Deltalite II 2515, at 157L and 44Hz. 119L loses 2dB from 40-50Hz. XP support ends in three weeks, time to move on.

[quote name='Balcro' timestamp='1395509673' post='2403250'] Just cover the end of the port on the inside. [/quote]On the outside, so that the air volume within the duct contributes to that of the enclosure. BTW Balcro, move up to the W7 version of WinISD, there are a lot more options, including max power, max SPL, and port velocity.

[quote name='geoffbyrne' timestamp='1395425546' post='2402402'] I've just looked at pics of the Basslite & the Deltalite II on Google, and it's defo the Deltalite. [/quote]Visually they're identical, they have the same frame. The only way to be sure is to measure the DC resistance. The Basslite is about 3.7 ohms, the Deltalite II about 5.3 ohms.

[quote name='Balcro' timestamp='1395407183' post='2402104'] I ran the parameters of the C2515 (2014) through winISD and quite closely matched Eminence's own "Cabinet design" for a large vented cab - (3.9 cu.ft). See here: - [url="http://www.eminence.com/pdf/Basslite_C2515_cab.pdf"]http://www.eminence....e_C2515_cab.pdf[/url] [/quote]He didn't say if he had a Basslite or Deltalite II, which are quite different. In may event the Basslite models best around 400L tuned to 33Hz, so it's a bit of an odd duck for bass unless you run drop tuned. 100L technically gives more power handling, but the loss in sensitivity offsets that. Maximum SPL remains the same above 42Hz, but it's less below that. Again, moot with a four stringer. The Deltalite in 150L with 44Hz tuning is much better than the Basslite in any configuration for four string. IMO the Basslite has no redeeming quailties save the 4 ohm impedance, which you might need running a single cab with some valve amps.

[quote name='geoffbyrne' timestamp='1395350204' post='2401542'] I know the guy who sold me the empty cab told me it was tuned pretty low. [/quote]If they're 200mm it's not tuned low, it's tuned high, around 50Hz. They should be no less than 250mm.

[quote name='JTUK' timestamp='1395223111' post='2399818'] ok..go careful then. If they are in good working order, then £50 sounds ok, but I am not sure many produced 12" at 300watts 20 years with that manufacturing pressed plate. [/quote]A stamped frame doesn't indicate all that much, though from the picture it's not possible to be certain whether they're stamped or cast. The cast EV SRO from the 1960s looked quite similar. The lack of a vented pole piece is far more telling, but that still doesn't reveal potential power handling. Not that power handling in and of itself matters, T/S specs are what one needs to determine the driver suitability.

Google it, they're a major driver and speaker manufacturer in Italy.

Search locally for something like this: http://www.homedepot.com/p/TrafficMASTER-Black-24-in-x-36-in-Anti-Fatigue-Vinyl-Foam-Commercial-Mat-60-571-0900-20000300/202015909

[quote name='andrewrx7' timestamp='1394702213' post='2394103'] does this linear array set up all go wrong when you add guitar amps into the mix? Do you end up with the comb filtering effect again? [/quote]You don't, the guitar amps do.

Headphones have very flat response and a wide bandwidth, bass cabs don't. I wouldn't judge an amp based on what you hear through phones.

[quote name='andrewrx7' timestamp='1394640986' post='2393619'] On a cab that quotes a frequency response from 60Hz, presumably porting would not offer much of an advantage then, assuming there is little effect from the ports from 80Hz upwards (Bill's post #8)? As ever, interesting reading, and thanks to Bill for sharing his knowledge. Does he ever sleep?? [/quote]Most ported cabs are tuned to 45-50Hz, and the bulk of their output there is from the port. Another factor is cone excursion, which is at a minimum at the tuning frequency. That means a ported cab has even more of an advantage over sealed in the low end in terms of maximum output, as the sealed will reach its excursion limits far sooner. The difference can be 10dB, which is the equavalent of 1000 watts versus 100 watts. [quote]Does he ever sleep??[/quote]I'm five hours behind you. Besides, I cruise the web just as most of you do, while at work. For me work is at my computer in my livingroom, and I don't have to worry about the boss peeking over my shoulder to see what I'm up to.

[quote name='charic' timestamp='1394632727' post='2393525'] I thought that if a cab was rear ported and near a wall it was different? I'm probably wrong though [/quote]Only if it's within an inch or two of the wall. [quote]I always thought front ports had more "throw" but I'm hardly technical minded [/quote]Look up the definition of 'omnidirectional'. Not only is port output omnidirectional, so is that from the cones up to about 200Hz.

[quote name='andrewrx7' timestamp='1394629644' post='2393461'] Does porting actually do much, or is it 90% hype?[/quote]A ported cab can deliver on average 6dB more output in the lows than sealed.That's the equivalent of doubling the cab count or quadrupling the power. But that's only in the lows, and it assumes a properly configured ported cab. There's no difference above roughly 80Hz. [quote]Does it matter if the ports are forward or rear facing? [/quote]No. Port output is omnidirectional.

[quote name='6v6' timestamp='1394617815' post='2393287'] Interesting! I was under the (evidently misguided?) impression that for bass cabs you had to avoid them being too shallow, so as to avoid reflections from the back of the cab interfering with the response of the driver?[/quote]Reflections from the back of the cab are controlled by lining the cab with damping. Or they're supposed to be, some manufacturers have been known to leave it out as a cost cutting measure. [quote]I have an open back 4x10 guitar cab which is only about 9inches deep, could I seal the back of it and put a new baffle in it with, say, a 15" driver? Edit: Yes I know I'd need to model the cab wrt volume and the driver specs.. [/quote]You could. The Eminence Beta 15 specs well for a sealed cab, it's similar to those used by Ampeg.