ricksterphil Posted May 27, 2016 Share Posted May 27, 2016 I have a Genz Benz 500 1x15 running at 8ohms 300w. By adding an extra speaker cab it will run at 4ohm and 500w I want to upgrade the standard speaker with a 600w 4 ohm job Will the amp automatically detect the 4 ohm setting or do I need to put a dummy speaking in the remote speaker out? Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted May 27, 2016 Share Posted May 27, 2016 [quote name='ricksterphil' timestamp='1464388430' post='3059209']... Will the amp automatically detect the 4 ohm setting or do I need to put a dummy speaking in the remote speaker out? [/quote] Yes, the amp doesn't know, or care, how many speakers are connected; only the final impedance presented. Change the 'standard' speaker and the amp will 'see' 4 ohms. You should not, henceforth, connect an extension cab, as this would bring the total impedance to below 4 ohms, and most amps don't like that. It would be helpful in such questions to state exactly which amp is being discussed, so as to be as complete as possible. Hope this helps. Quote Link to comment Share on other sites More sharing options...
EBS_freak Posted May 27, 2016 Share Posted May 27, 2016 The question I'm gonna ask is why you are changing it? It won't give you any significant difference in volume and if the TS parameters of the replacement speaker is different, you could end up with a less than ideal sounding cab. If you like your tone and just want more volume, add another speaker cab. To answer your question, the amp doesn't care what the load is as long as it isn't less than 4 ohms. So you could achieve that by typically one four ohm speaker or two eight ohm speakers in parallel. (Or one four ohm cab and two eight ohm cabs in parallel - as cabs may contain multiple speakers) Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted May 28, 2016 Share Posted May 28, 2016 [quote name='ricksterphil' timestamp='1464388430' post='3059209'] I have a Genz Benz 500 1x15 running at 8ohms 300w. By adding an extra speaker cab it will run at 4ohm and 500w[/quote]Only if the second speaker is 8 ohms. [quote]I want to upgrade the standard speaker with a 600w 4 ohm job[/quote]Going to a higher thermal power rating doesn't mean it's an upgrade. It's far more complicated than that. Quote Link to comment Share on other sites More sharing options...
ricksterphil Posted May 28, 2016 Author Share Posted May 28, 2016 Ok thanks folkz I've already got the upgrade speaker as it happens so I'm going to fit it and see if there's an improvement. If not, there may well be a speaker for sale....bought it off here anyhow Didn't want to go the extra cab route and have to lug it around + we play small venues - standingnexttodrummerbassinBillWhymanposition - sort of thing, so there often isn't room for extra gear Quote Link to comment Share on other sites More sharing options...
chris_b Posted May 28, 2016 Share Posted May 28, 2016 An extension cab will usually only raise the height of a rig and not increase the footprint. If space is an issue I'd get a couple of good 112 cabs. I used to use 2 Bergantino AE112 cabs. Only slightly bigger than your combo and a great sound. Quote Link to comment Share on other sites More sharing options...
bigjimmyc Posted May 28, 2016 Share Posted May 28, 2016 (edited) I think I see your point. You have the new driver and are hoping for more power by swapping out the existing driver. There's some mileage in this if (a) you're not going to use a second cab and (b) this 600W 4ohm driver is a big improvement on the existing 300W 8 ohm one. It will allow you to use your amp's full output capability. However, not all cabs are "compatible" with all drivers. Thermal efficiency isn't the only variable which could scupper your plan, but the only way to know if you've got a winning combo (excuse the pun) is to try it. I would! Tons of advice available here. I suggest you post as much info as you can about the amp, the drivers, the cab itself etc if you want to leverage the assembled brains. Edited May 28, 2016 by bigjimmyc Quote Link to comment Share on other sites More sharing options...
bigjohn Posted May 28, 2016 Share Posted May 28, 2016 (edited) [quote name='bigjimmyc' timestamp='1464440828' post='3059486'] There's some mileage in this if (a) you're not going to use a second cab and ( this 600W 4ohm driver is a big improvement on the existing 300W 8 ohm one. [b]It will allow you to use your amp's full output capability[/b]. [/quote] It will but the relationship between volume and power isn't linear. Swapping out a 300W 8Ohm driver for the equivalent 600W 4Ohm driver will produce very little, if any noticeable increase in volume, the only thing it will do is draw more power from the amp and create more heat. The result of which is likely to be a less reliable amp, which draws more power and runs hotter, not a louder one. The OP might be lucky that this produces a characteristic that they like. Good luck. Edited May 28, 2016 by bigjohn Quote Link to comment Share on other sites More sharing options...
chris_b Posted May 28, 2016 Share Posted May 28, 2016 Running an amp at 4 ohms does not make it less reliable than running it at 8 ohms!! Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted May 28, 2016 Share Posted May 28, 2016 [quote name='chris_b' timestamp='1464445385' post='3059519'] Running an amp at 4 ohms does not make it less reliable than running it at 8 ohms!! [/quote]True. OTOH going to a 4 ohm driver "to get all of the watts out of my amp" will at best result in a few dB of additional output, and depending on the driver specs it could actually have less output. This is of course totally predictable, using speaker response modeling software, but as the OP decided to leap before looking I give it a 50-50 shot that we'll see a 600w 4 ohm driver appearing in the classifieds in short order. Quote Link to comment Share on other sites More sharing options...
ricksterphil Posted May 28, 2016 Author Share Posted May 28, 2016 I will be making said mod shortly and will let you know the results. Thanks for all the input guys Quote Link to comment Share on other sites More sharing options...
bigjohn Posted May 28, 2016 Share Posted May 28, 2016 (edited) [quote name='chris_b' timestamp='1464445385' post='3059519'] Running an amp at 4 ohms does not make it less reliable than running it at 8 ohms!! [/quote] All else equal it does. It will create more heat, meaning the transistors will, over time become more stressed. Whether or not that translates into this or that particular amp is not the point I was making. I had an amp that continually blew the power transistors even though it was running cabs it was rated for. Rewiring the cab so it was 16Ohm and not 4Ohm solved it completely. Edited May 28, 2016 by bigjohn Quote Link to comment Share on other sites More sharing options...
HowieBass Posted May 28, 2016 Share Posted May 28, 2016 I think I'm right in saying that two drivers with a combined load of 4 ohms will be louder than a single driver of 4 ohms because you're moving twice as much air; so don't expect the new 600W speaker to give you the volume increase you'd hear with an extension cab. Quote Link to comment Share on other sites More sharing options...
EBS_freak Posted May 28, 2016 Share Posted May 28, 2016 [quote name='HowieBass' timestamp='1464453208' post='3059599'] I think I'm right in saying that two drivers with a combined load of 4 ohms will be louder than a single driver of 4 ohms because you're moving twice as much air; so don't expect the new 600W speaker to give you the volume increase you'd hear with an extension cab. [/quote] If the speakers are identical and receiving the same power as the single speaker. Quote Link to comment Share on other sites More sharing options...
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