stevie

[quote name='Twincam' timestamp='1476630887' post='3155784'] Looking online it seems its just held in with 4 screws on the top. So it should slide out from the back or the front. Try pushing it from the back first. [/quote] I've tried pushing, pulling, banging and levering, and believe me, it is stuck. There are screws top (and bottom) holding the amp in the casing, but there has to be something else as well.

[quote name='BassBunny' timestamp='1476625881' post='3155710'] The fan shouldn't be related to Volume. There are 2 types, those that are on all the time and those that are temperature sensitive and only come on when the temperature in the case rises above a set level. So it depends on which type it is. [/quote] Yes, that's what I'm trying to find out. I can hear the internal fan, which is on all the time. As I'm using it at home at a low volume at the moment, the amp is not getting hot. It could well be that it only switches in when the amp gets hot, in which case all is fine. However, if the fan is faulty and I gig the amp, I could blow the amp and my speaker. The reason I want to get inside the amp is to test the external fan. Even then, it could be the thermistor switch that's faulty, which is why I'd like to know if the fan should be turning at low volumes. I'd give Behringer a call, but it's Sunday and I'm not sure I'd be able to find someone to answer the question anyway.

I've taken all the visible screws from the wooden case on my Behringer BX4500 head and the thing won't come out. It's solid. I even looked under the corners in case there were hidden screws there. Come someone tell me what I am missing? I haven't played this at loud volumes yet, but the fan on the back panel doesn't come on at low volumes. Is this normal?

It's likely to be the 12 K 3 PL model - 700 watts programme. There's only a certain amount you can glean from spec sheets, but it looks to be in the same ballpark as the Eminence offerings.

[quote name='obbm' timestamp='1474634081' post='3139448'] In addition they are response for post-sales warranty so if your Prodigy dies it will have to back to them for it to be fixed at their cost, assuming that it is still within the warranty period. All of this is paid for from the mark-up on the products they are selling.... [/quote] Sorry to nitpick, because I agree with everything else you have said, but the manufacturer normally refunds the distributor for repairs they have to carry our under warrranty. So that's not one of their costs.

Yes, kerbs and stairs are probably the big problem for dolly boards, although I've never used one myself. My trolley is a sack barrow type. I want to avoid cutting holes in my cab for rear castors, or spending money on a dolly board for that matter, when a separate trolley (which I already own) is the best solution anyway. I think I'll give the trolley a go first. Unless someone has a convincing argument in favour of another solution. Thanks for the input!

That's a step too far in the woodworking department for me, Mark. So the Barefaced uses 3-inch castors and large rubber feet at the front to make the cab level. OK. This is a lot more complicated than I expected.....

[quote name='bertbass' timestamp='1476291212' post='3153120'] 3 inch might be better as cracks in pavements etc, won't be noticed as much but you might have to raise the front of the cab a bit so that it's level. Another option is 4 wheels on the bottom of the cab and turn it on its side when in use it then becomes a high dolly and you can wheel loads of gear in at once. [/quote] OK. I think I get that. So with 3-inch inset wheels on the back, the cab would not be level. Would larger rubber feet on the front fix that, or not? The cab design is vertical and won't work properly on it's side. 4 wheels on the bottom should be OK in my limited experience, but it might be a bit top-heavy when moving it.

I'm now more confused than when I asked the question. So is a dolly board a better solution than a trolley or permanently attached castors?

[quote name='deksawyer' timestamp='1476275699' post='3152896'] What's your opinion on active versus powered? [/quote] If you already have a power amp in-cab, you are throwing away a lot of the benefits of digital technology and DSP by not using an internal active crossover. The HF power amp section doesn't have to be as powerful as the main one - so the weight penalty isn't huge. An electronic crossover allows you to time-align the drivers accurately and use steeper slopes than you would otherwise use. Plus, you can then tailor your limiting so that it acts independently on each individual driver, which helps with reliability. The downside is that there is an extra cost involved. Technically, it is a superior solution, which is why all the top-end active cabs use this approach - and even some cheapo ones like the Alto TX12, which cost about £150 each. I'm a great fan of passive speakers personally. But that's a different kettle of fish and they do have to be done properly.

[quote name='stingrayPete1977' timestamp='1476268422' post='3152808'] I didn't know they were active! [/quote] It doesn't look like they are active. They are powered. I think most people would expect an active system (two power amps and an electronic crossover) for that money.

I was wondering about what size to use. Wouldn't 3-inch be better?

I'm in the middle of building a 15" cabinet about the size of the Ashdown ABM or Trace 1153 and am looking for some pointers on wheels. I have a set of 3" rubber wheels on my Ashdown Mini 15 and they work quite well, but I'm unsure of whether they will be right for this larger cab. So I'm thinking either 4 x 4" castors (probably a bit big) or those recessed castors that fit into the bottom edge of the cab allowing you to tilt and roll. A top handle is in place that would allow for this. http://www.penn-elcom.com/default.asp?MC=01120801&LG=ENG&title=corner-castors What are your experience with those - positive or negative? Or would I be better off with my aluminium trolley?

I agree with the others. It's a choke. It's got to be from the tweeter circuit because if it was from the LF circuit you wouldn't have any sound from the main driver now. It sounds like it hasn't been fixed down very well and was held on mainly by two soldered wires, which have snapped off. You need to trace the wiring from the L-pad (the tweeter volume control) back towards the input. It should lead to the crossover. If there is enough wire sticking out of the choke, you might be able to repair it - otherwise you'll need a new choke. If this assumption is correct, you are now putting excessive power through the tweeter. So you really need to fix it, even though it might not sound any different.

Sounds like all root notes to me. One sustained note per bar, with an eighth note lead-in every once in a while at the end of the bar and an occasional octave. You put your finger on it yourself. It's country. Keep it dead simple.

I've re-checked one cabinet that I have here with a slot port, and my software is 100% accurate compared with the impedance measurement. I also recalculated the Cab Diary speaker and it's only 2Hz away from what we actually measured. Just for information, really, as what matters is the actual measurements on the cabinet.

Yes, I think you're right, Phil. See my comment in the Beyma thread that's currently running.

Looks OK. I get 89 litres tuned to 44Hz, although since my recent failures with my tuning software I'd take the latter figure with a grain of salt. The limiting factor is the size of the ports. Increasing them to 4" diameter (by 5" long, but perhaps someone would double-check) would help, if that's possible. The low end response is 15dB down at 40Hz. Excursion-limited power handling would be close to 500 watts, which is pretty good.

[quote name='Phil Starr' timestamp='1475523712' post='3146671'] I think he may be as old as we are Stevie [/quote] Sounds like it, Phil.

Inches? Really?

BoB said earlier that they have a "proper" crossover and not just a high pass filter. If it's a 2nd-order crossover designed for 4 ohms, connecting it to an 8-ohm load will cause a nasty peak in the midrange and pull the impedance down below nominal. If it's just a 1st-order (inductor only), it will lower the crossover frequency and depress the mids. Either way, not good.

Really appreciate this. Thank you.

Fascinating! John, I just re-entered the numbers in your last post into my software and get 57Hz for the slot port, which is still quite a bit off. My software is actually deducting volume for the port and the driver, which should make it more accurate, but there's obviously something wrong that I can't quite figure out yet. I did the same with cab no. 2 and get 55Hz compared with your measured 61Hz. That's also rather disappointing. Bassbox Pro is usually spot-on with round ports, as we found when we meaured Phil's prototypes. When I have a bit more time, I'll have a fiddle with WINisd, although I believe Phil uses WINisd and he got the same figures as I did in our earlier calculations. I really like your side-ported version, by the way, as it leaves space for an optional tweeter or midrange driver. Phil originally built a slot ported cab, but with the ports at the end of the box. We discarded that because of a nasty standing wave that was not present in the box with round ports. We assumed at the time that this was because the slot port had made the internal dimensions square . This thread would indeed make a useful addition to the Cab Diary. Maybe one of the mods could pick it up and stick it on the end. [Edit] I would just add that your measurements demolish my theory that cab mis-tuning was the cause of your damaged driver.

It seems to be a common problem with DJs. Otherwise, I agree: it's not as common as it used to be.