Hammer_ Posted December 8, 2021 Author Share Posted December 8, 2021 2 minutes ago, mybass said: I may have missed something here but…….Dual channel or stereo amplifier? A dual channel runs as mixing two inputs into a mono output signal whether using (one 8 ohm)or both speaker (16th ohms) outs to your two cabs…. A stereo amp will allow two separate load outputs for two separate speakers….8 ohm load per cab. Stereo 1 Quote Link to comment Share on other sites More sharing options...
itu Posted December 8, 2021 Share Posted December 8, 2021 8 hours ago, Chienmortbb said: If we assume that both amplifier amd speaker are substantially linear, then the correalation between watts and SPL is also linear. Do agree. But when people change cabinets, watts and decibels behave depending on the efficiency, frequency response et al. just because the cabs are different. Bass response and cabinet volume and efficiency are related, as we all know. If I want to equalize two different cabinets to match each other for similar sound (response), watts play a role, but then watts are not automatically equal. Similar loudness may need substantially different amount of power. This is why I do not see the relation being very strong. Watts do matter, but how to compare rigs, if the loudness (dB) is unknown? Yes, we should know some vital specs from the amp and the cab. These are not published often, i.e. we are not given enough data to be able to compare different rigs. We need decibels, but marketing department says: "Watts!" Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted December 8, 2021 Share Posted December 8, 2021 14 minutes ago, itu said: Do agree. But when people change cabinets, watts and decibels behave depending on the efficiency, frequency response et al. just because the cabs are different. Bass response and cabinet volume and efficiency are related, as we all know. If I want to equalize two different cabinets to match each other for similar sound (response), watts play a role, but then watts are not automatically equal. Similar loudness may need substantially different amount of power. This is why I do not see the relation being very strong. Watts do matter, but how to compare rigs, if the loudness (dB) is unknown? Yes, we should know some vital specs from the amp and the cab. These are not published often, i.e. we are not given enough data to be able to compare different rigs. We need decibels, but marketing department says: "Watts!" Yes but amplifiers supply WATTS to an impedance. 1 Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted December 8, 2021 Share Posted December 8, 2021 (edited) 9 hours ago, Chienmortbb said: If we assume that both amplifier amd speaker are substantially linear, then the correalation between watts and SPL is also linear. The problem is that assumption is incorrect, in a few ways, the most obvious being that speaker impedance, and as a result current and power, isn't a constant with respect to frequency. That's why neither amperes nor watts are used in SPL computations. Volts are, being unaffected by the load impedance, and being linear with respect to cone excursion. Quote Yes but amplifiers supply WATTS to an impedance. See paragraph above. Edited December 8, 2021 by Bill Fitzmaurice Quote Link to comment Share on other sites More sharing options...
Downunderwonder Posted December 8, 2021 Share Posted December 8, 2021 11 hours ago, Chienmortbb said: This is almost correct. If we assume that both amplifier amd speaker are substantially linear, then the correalation between watts and SPL is also linear. As we approach the limits of either amplifier of speaker the linearity can reduce. Bill tried to set you straight. In more layman's terms, about the only thing that is linear in the whole operation is the numbers 1 to 10 on the amp dial. SPL is on a log scale to 'match' with voltage and make graphs possible to fit on paper. It also dovetails with how we hear changes in SPL. If you know anything about power, it varies with the square of the voltage. Decidedly non linear! While the heat remains under control you can get 3dB extra volume each time you double the power. A very non linear 1w 2w 4w 8w 16 32 64 128 256..... 512.. silence. Rules of thumb might have changed a little in the modern high power woofer game but it used to be that around half the rated power through put was where they would start to get warm and go 'non linear' not that they were ever linear in the first place. OP's 800w cabs will do very well with 480w each. 2 Quote Link to comment Share on other sites More sharing options...
agedhorse Posted December 9, 2021 Share Posted December 9, 2021 16 hours ago, mybass said: I may have missed something here but…….Dual channel or stereo amplifier? A dual channel runs as mixing two inputs into a mono output signal whether using (one 8 ohm)or both speaker (16th ohms) outs to your two cabs…. A stereo amp will allow two separate load outputs for two separate speakers….8 ohm load per cab. A dual channel amp can in fact be used to describe a stereo amp and the other way around. It depends on the product. 2 Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted December 9, 2021 Share Posted December 9, 2021 Watts clearly do matter or a 1W amp would be as loud as a 1000W amp. It defines the rate of energy transfer https://en.wikipedia.org/wiki/Watt You don't need to get into a technical feeding frenzy however, watts depend upon both volts and current and in a practical amplifier they aren't independent. You don't need to understand that though just read your manual You get 800w at 4ohms and 480 per channel at 8 ohms or 960W in total at whatever distortion level your manufacturer chose to measure this at. Marginally more power using both amps. Not enough to be noticeable soundwise but more. More importantly the current flowing in each amp will be lower and high currents will create heating and other effects within each amp which might mean losing some power over long term high level use. I think your answer is in this part of what you've said "2 x BBII yes they are loud. But I don’t feel the same heft and pure power like you do when playing in front of an ampeg SVT / 810 rig." There are a whole lot of differences between a monstrous wall of cheap drivers driven by an SVT and a modern FRFR speaker system with it's 'hi fi' sound. The 810 is going to be more efficient and highly coloured with lots of frequency bumps in the response which you are hearing as heft. The poor Barefaced had all of that removed to give you a cleaner sound. Finally I wouldn't pay too much attention to the clipping light. It's only showing that you have signal. Your manual says listen to the speaker output to verfy operation 2 1 Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted December 9, 2021 Share Posted December 9, 2021 (edited) double post Edited December 9, 2021 by Phil Starr Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted December 9, 2021 Share Posted December 9, 2021 (edited) On 08/12/2021 at 22:27, Downunderwonder said: Bill tried to set you straight. In more layman's terms, about the only thing that is linear in the whole operation is the numbers 1 to 10 on the amp dial. SPL is on a log scale to 'match' with voltage and make graphs possible to fit on paper. It also dovetails with how we hear changes in SPL. If you know anything about power, it varies with the square of the voltage. Decidedly non linear! While the heat remains under control you can get 3dB extra volume each time you double the power. A very non linear 1w 2w 4w 8w 16 32 64 128 256..... 512.. silence. Rules of thumb might have changed a little in the modern high power woofer game but it used to be that around half the rated power through put was where they would start to get warm and go 'non linear' not that they were ever linear in the first place. OP's 800w cabs will do very well with 480w each. Bill and you are correct as my comment missed one vital parameter, frequency. It assumes a fixed frequency and ignores the effects of power compression. I am also fully aware of both the power law and ohms law and it is nice to see others are too. Edited December 10, 2021 by Chienmortbb Quote Link to comment Share on other sites More sharing options...
BassmanPaul Posted December 9, 2021 Share Posted December 9, 2021 20 hours ago, Downunderwonder said: Bill tried to set you straight. In more layman's terms, about the only thing that is linear in the whole operation is the numbers 1 to 10 on the amp dial. SPL is on a log scale to 'match' with voltage and make graphs possible to fit on paper. It also dovetails with how we hear changes in SPL. If you know anything about power, it varies with the square of the voltage. Decidedly non linear! While the heat remains under control you can get 3dB extra volume each time you double the power. A very non linear 1w 2w 4w 8w 16 32 64 128 256..... 512.. silence. Rules of thumb might have changed a little in the modern high power woofer game but it used to be that around half the rated power through put was where they would start to get warm and go 'non linear' not that they were ever linear in the first place. OP's 800w cabs will do very well with 480w each. Y'know Bro. You ain't as dumb as I look!! LOL Quote Link to comment Share on other sites More sharing options...
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