escholl

This is absurd, the hissing has nothing to do with amplifier class. That particular hissing is white noise, and if the level of hiss is dependent upon the preamp volume as was mentioned, then the hiss is very likely from the thermal noise generated by high value resistors early on in the signal path. Amplifiers do no hiss like that because they are a certain class, they hiss because they have gain and deal with real-world physics and components. Some amps are quieter than others simply because they may be better designed or use a higher grade of components.

You may also want to check out these books, sorry if a few may have been mentioned I haven't checked: Everest, F. Alton - Sound Studio Construction on a Budget. Gervais, Rod - Home Recording Studio: Build It Like the Pros. Newell, Phillip - Recording Studio Design

[quote name='nash' post='917322' date='Aug 6 2010, 07:28 PM']It powers up and goes into some kind of error mode with multiple lights on and no sound. Contacts etc have been cleaned etc[/quote] Ok, it could be the EPROM or FPGA being faulty, or it could be traces of water under one of the IC's shorting a logic high or low, or messing with the clock signal -- try the rice thing, you could also try cleaning the two main IC's with IPA, make sure you really get it underneath and then blow it out with some canned/compressed air, this should help remove the water if there is any underneath. By the way, I meant the EPROM contacts, not the I/O jacks, just in case there was any confusion.

[quote name='dave_bass5' post='915786' date='Aug 5 2010, 12:01 PM']Not true unless you are talking about the Line6 specifically and it does this. If so then ignore my post. At last Sats gig we had the DJ's mic coming through our singers guitar amp as both were transmitting on the same freq. In the past ive also had my bass being picked up by the video crew's radio system. This is one reason i use a multi freq AKG system now. Its only been a handful of gigs that we have had any trouble as we dont normally play with out bands/DJs but you can certainly pick up other devices transmitting on the same freq.[/quote] This sort of interference was common with analogue systems, however the Line 6 uses A/D and D/A conversion, and transmits the data digitally in a fashion not dissimilar to a mobile phone, although much higher quality. The "channels" on the Line 6 unit aren't real channels, in the sense that they don't change the broadcast frequency, what the "channel" switch changes is simply the address of the data, as only receivers tuned to that data address will decode the broadcasted signal.

If it's just the EPROM it will be a cheap repair for them, and should be for you. If it's the FPGA or whatever other microcontroller might be in there, it may be a bit more. Crazy as it sounds, try putting it in a bag with lots of dry rice, and let it sit there for a couple weeks. That sometimes will suck out the excess moisture that might remain and can get things working again. The other thing you can try might be (carefully) re-seating the EPROM, and cleaning it's contacts, as water can sometimes make them corrode enough to stop conducting. is the unit completely non-responsive? no lights, no sounds, nothing?

[quote name='M4L666' post='916936' date='Aug 6 2010, 01:20 PM']have different drive settings, one clean, one dirty and one distorted or something like that[/quote] this.

so, does it do both at once, or one at a time? also, the design looks cheap -- might be well made, but it [i]looks[/i] cheap.

i've just noticed this, congrats Sarah, well done to you! hope to be doing it myself one day, assuming i'm clever enough that is! ^_^

[quote name='Mr. Foxen' post='916204' date='Aug 5 2010, 05:24 PM']Boo! Matamp.[/quote] this. head + 8x10 or 2 1x15's and you're good to go for anything.

[quote name='cheddatom' post='916073' date='Aug 5 2010, 03:07 PM']How come?[/quote] In my experience, it's really not up to the same standards as Logic or Protools LE or HD system, or even Sonar for that matter -- I found some particular things about the user interface to be rather frustrating versus other DAWs. Sonically, there is not any difference, it's all down to the workflow ease and user interface. I know a lot of people use it and like it, but for a studio, it would not be my recommendation. Also, if he is hoping to get some business out of this, for compatibility reasons it would be best to use Protools, followed by Logic -- this allows artists and producers to directly import any projects into the system in the formats they are most likely to have used to create the project in another studio, in addition to giving the greatest amount of familiarity to anyone else who may be using the system.

[quote name='Beedster' post='915968' date='Aug 5 2010, 01:54 PM']I think I'm going to start looking at the control room first, specifically recording media and desk. I would really appreciate your thoughts on the following: Mixing desk 1. how many channels? 2. new or used? 3. dedicated software model (i.e., designed to work with computer), or generic 4. best manufacturer/models? Computer/software 1. laptop/desktop? 2. PC or Mac? 3. Software? Cheers C[/quote] How much of your 20K are you looking to spend on a mixing desk? Remember you will need all the less glamorous things too like acoustic treatment (and plenty of it -- it's not all about sound proofing, but room acoustics! A good recording starts with a good room, good mic technique, and a good mic -- everything after that is a correction, so make sure you've got a good room!) and cabling, stands, racks for any rackmount equipment, etc. Anyways, what I would say is that before getting a desk you should decide what system you are going to use. I would choose a Mac desktop for this, which leaves either logic or protools (or cubase...but i would suggest not using cubase). Now, there's a variety of choices you've got here. You can run a fully analogue desk, and use the Mac effectively as a tape machine, recording through the desk pre's, then through the tape sends on each channel, and mixing down through the returns -- a good system but you won't have any control of the DAW through the desk. Or, you could go the other way, and feed some rackmount mic pre's straight into the soundcard, and use a control surface to control the DAW. This second option is what I would most likely choose to do. If you start with 16 channels that should be enough for most things, and then get a control surface to let you control the DAW. Remember, protools has their own line of DAW controllers, so if protools is the path you want to take, you will need to take that into consideration as well.

[quote name='mrtcat' post='913918' date='Aug 3 2010, 02:43 PM']Much of what you say tally's perfectly especially the tripping out the electrics on start up.[/quote] [quote name='High score' post='914237' date='Aug 3 2010, 08:24 PM']Tripping on start up can be cured. There is actually a thread on this site about it already. Audiolabs do a permanent internal fix but not exactly cheap - especially when the parts cost around £1.50.[/quote] Just in case you are wondering one of the threads, and solution, is [url="http://basschat.co.uk/index.php?showtopic=47105&hl=ampeg+start"]here[/url].

If anything, taking the DI out before the amp will actually work to your advantage -- then the sound engineer can EQ the sound exactly as he needs it to be, without having to fight your amp EQ or deal with any compression you may have applied. Then you can use your amp EQ and comp/noise-gate to precisely tailor your on-stage sound, and let the engineer deal with FOH. Sorted!

Given the time, effort and money that can be spared by putting in a 7p diode, I really would advise not leaving that polarity protection there out

There are instances where more power is not better, however solid-state bass amps are not one of those cases , and in this case I think you should likely get the most powerful combo that you can afford. Besides, that T15 looks nice!

[quote name='stevie' post='910462' date='Jul 30 2010, 05:29 PM']I used Liberty Audiosuite, an industry-standard measurement system, to measure the Thiele Small parameters of the driver straight out of the box. I used the added weight method to find VAS. I ran the driver in with a 20Hz signal from a signal generator into the unmounted driver for about 4 hours, I think. I normally leave them running overnight but fs had dropped to below the manufacturer's spec - so I thought that was enough. If I’d known the data was going to be nitpicked, I would have measured several times to eliminate some of the inconsistencies. The only thing that running-in does is to reduce the stiffness of the suspension. So, VAS is raised and fs and Qts drop. If you compare the green and blue curves of the simulation, you will see that these changes are self-cancelling because the curves for both drivers are virtually identical. (There seems to be a few bugs in my modelling software, because the f3 point is obviously the same, and not different as it states, and there is also a contradiction in the nominal efficiency figures and the 1W SPL figures.) Still, it’s the big picture that counts :-). My conclusion would be that running a speaker in makes no difference to its frequency response when mounted in a reflex or sealed enclosure. I would expect the lower fs after running-in to be audible in a dipole, or an open-backed guitar cabinet, however, because VAS is more or less irrelevant to the performance of these boxes. Horns, as mentioned by Lawrence, may be similar, but that’s not my field. Al, the measured frequency response differences of the 'before and after' driver mounted in a cabinet are negligible. I would not expect any audible difference. If there is an audible difference between a driver before and after running in, I have no idea what might be causing it, but I think escholl put his finger on the most likely cause earlier on. Did anyone mention cable burn-in?[/quote] Thank you for posting all that. So, as I understand it, 4 hours (or possibly less?) of use may make a slight difference to the low end response of a dipole enclosure, otherwise the difference is negligible?

Wish I wasn't overseas with all my extra bass bits back in the UK, but I have to say Jack you sound like a really awesome mate to have around, she is lucky Also seeing the way everyone comes together for stuff like this never fails to make me smile.

[quote name='wotnwhy' post='909683' date='Jul 29 2010, 09:49 PM']DI the bass drum? [/quote] Isn't that what the hole in front is for? I always thought it just took a BIG xlr jack...?

[quote name='stevie' post='909493' date='Jul 29 2010, 05:55 PM']Here is some data on an Eminence Kappalite 3012LF, with measurements before and after running in. There are a few minor discrepancies, but this was not designed as a scientific exercise: I was simply checking the parameters against the manufacturer's figures. The parameters on the left are for the new driver; the ones on the right are the same driver, but run in. The interesting information is on the right - a simulation of how they perform in an identical box. I can't say this is conclusive and absolute, but it's certainly repeatable by anyone who wants to do so.[/quote] This is very interesting actually, can you give us more information on exactly what you did, and how you measured and obtained these results? What was your break-in procedure? Rms has lowered, indicating the suspension's mechanical resistance has dropped slightly, however Vas and Mms have gone up (to approximately the published specs), while Cms has also dropped. Fs has dropped as a result, which is intriguing, however when comparing to Eminence's published specs I would be interested to know what the margin of error was for this experiment. Qes has also dropped, indicating the speaker is better damped electrically than it was initially. Also, f3 has dropped by 12 Hertz for an identical enclosure. At this rate, it looks like I could well be wrong on this occasion! But I'd like to know more about exactly what you've done.

[quote name='LawrenceH' post='909456' date='Jul 29 2010, 05:06 PM']>"what he hears" >"my own aural 'observation'." >"He reckons" >"I trust my ears more than I'd trust the rubbish testing conditions/aparatus"[/quote] Your ears can be surprisingly good liars. You hear what you expect to hear. If you have any friends who are music producers or mixing engineers, ask them if they've ever accidentally used an EQ which, in fact, wasn't connected or engaged -- but they didn't realise till after they'd "gotten" the sound the wanted. It's happened to me, it's happened to a few people I know -- you feel silly, but it demonstrates to what extent you can hear what you expect to hear. This is why you need to measure, and not trust your ears. Notice how speakers never sound worse when they're broken in? If speaker break in was a "thing" there is no way that would be true in every instance. I listen to the same speakers everyday. Usually a lot of the same music too. Sometimes, they sound a lot different than they did the day before -- have they changed? Well, they're 37 years old, so I'd say they're probably broken in by now.

[quote name='4 Strings' post='909162' date='Jul 29 2010, 12:55 PM']Worn out? Didn't know they wore, no moving parts touch, if the coil or suspension goes, it goes.[/quote] +1

[quote name='3V17C' post='909247' date='Jul 29 2010, 02:02 PM']yeah could do that.. was just thinking that i won't get the full 575watts then though with an 8ohm cab on each ?....[/quote] No, but you will likely get out more power overall using one amp per cab. Also, as previously mentioned, this way each amp shares the load, reducing the demand on each output stage and thus increasing reliability, etc.

[quote name='Mr. Foxen' post='908797' date='Jul 29 2010, 12:58 AM']Nerd fight![/quote] but on a nerdy note, I had this discussion with him once, and told him that when he could provide the objective data I would be all ears. He never did, but he is pretty busy. Till then, I stand by my statement however. I will be doing a masters in audio acoustics this year or next, and am planning a doctorate after that, so hopefully I will finally be able to resolve this once and for all in the next few years!

that's amazing news, nice one mate!

I've got an SKB Bass Safe, it's really well made and seems just about indestructible. Assuming that build quality extends to all of their models, then I would definitely say go for the SKB, especially at that price!