Bi-amp front speakers with receiver (internal) and external integrated amp?

[antcollinet]

That works well. A smaller power amp on the high end (tweeter and or mid) is good because the actual amount of power going to the high end is way smaller than the woofers low end power requirement.

you still need the same gain for both amps or you end up with a massively non flat frequency response.

 

[antcollinet]

I know what I hear and I have managed to clean up a few things in the sound, it's not an imaginary result it's a result that can be heard.

Well so are results that are percieved as a result of cognitive biases - when there is no change to the sound. They can be heard too.

However, in your case you seem to be influencing the frequency response of your speakers - so probably an audible change. Here you need to be carful about ascribing "better sound" to what you are hearing. You are simply hearing "what you prefer" in your room with your speakers. This may or may not sound better to others.

IOW don't mix up "preferred" with "better". Preferred simply means "better for me"

You also need to realise you can make exactly the same changes to the frequency response - without bi-amping.

 

[hwest]

Well so are results that are percieved as a result of cognitive biases - when there is no change to the sound. They can be heard too.

However, in your case you seem to be influencing the frequency response of your speakers - so probably an audible change. Here you need to be carful about ascribing "better sound" to what you are hearing. You are simply hearing "what you prefer" in your room with your speakers. This may or may not sound better to others.

IOW don't mix up "preferred" with "better". Preferred simply means "better for me"

You also need to realise you can make exactly the same changes to the frequency response - without bi-amping.

Although I don't put a big emphasis on the measurements I do always take measurements to ensure this is not "Imaginary" and definitely see changes there as well so you can say it's imaginary but when I can tone down or up the levels independently on the highs and lows that has some value that you are not wiling to realize, and I will see that when I roll off those highs in addition to levels, again all considered you must consider all and I don't think you are. I do use ARC Genesis and REW sometimes so I understand what we can do with the the features in my unit also familiar with Dirac which I use in my bedroom setup. I hope you're hearing me when I point out these values and to suggest you're sitting in front of my system telling me what I hear is a bit arrogant to be honest.

 

[antcollinet]

Although I don't put a big emphasis on the measurements I do always take measurements to ensure this is not "Imaginary" and definitely see changes there as well so you can say it's imaginary but when I can tone down or up the levels independently on the highs and lows that has some value that you are not wiling to realize, and I will see that when I roll off those highs in addition to levels, again all considered you must consider all and I don't think you are. I do use ARC Genesis and REW sometimes so I understand what we can do with the the features in my unit also familiar with Dirac which I use in my bedroom setup. I hope you're hearing me when I point out these values.

I don't think I was telling you it is imaginary.

However, in your case you seem to be influencing the frequency response of your speakers - so probably an audible change.

When you say you do measurements - what have you measured as different between bi-amped, and not bi-amped?

 

[Doodski]

you still need the same gain for both amps or you end up with a massively non flat frequency response.

I'm onboard with what you say and it's been a nagging question for me for ~31 years since I built my first active crossover speaker system.
I have questioned this amplifier power balance between the drivers and resulting frequency response non-linearity issue associated with for example a 3-way active crossover system using the 3 amps of sizes ranging from:
- 60 W/ch amp for the KEF Reference Series tweeters.
- 100 W/ch amp for the Altec Lansing high efficiency midrange tuned horns.
- 250 W/ch amp for the KEF woofers in a transmission line cabinet.

When the system was operational for several+ years @ home I was preoccupied with my techy service work and I never had the extra time or the want to transport my always in use test gear to my home so that I could meter the tri-amplified active crossover system to see what was occurring and to see if there was clipping on one of the amps when the system was used more aggressively which occurred fairly often.

I was not using a calibrated mic with software as we have today to calibrate the system. The tuning was all done by ear.
I have a propensity for setting a PEQ or tone controls to unusual levels due to what sounds good to my ears and so I'm not so sure if I would go with a mic calibration method anyway.
I used a pink noise calibration method with a spectrum analyzer and calibrated mic on a previously owned passive crossover type system and the result sounded horrible although admittedly very sharp, detailed and clear sounding. I was not sure if that could have been deemed an accurate sound. I was therefore not interested in using that method on my tri-amp'd active crossover system.

I did for the sake of personal interest perform active crossover system amplifier power output calculations/estimations when I studied electron flow principles and when the math operations where fresh in my mind. The figures indicated the amplifier power output levels varied considerably from driver to driver in a standard driver configuration; meaning not using horns for midrange. Using the Altec Lansing horns and compression drivers for the midrange drivers as I did would make for less power required than required for the KEF midrange driver that I had used previously. So with the use of high efficiency horns, transmission line cabinet, and varying sizes of amplifiers one would think there would be severe imbalances in the dB output of each driver causing a very poor balance between the drivers and making for some very narrow range of operation where the system would sound good. Otherwise the frequency response outside of that sweet spot would be abysmal.

The sound quality across the volume settings ranging from (Not low.) a medium to high dB output was very enjoyable and there was no need to tweak the bass and treble controls or adjust the active crossover settings.

So regarding the topic @ this present time I am reacting on lived experience, some memory of the actual science/maths and estimations that I make up in my mind.
Is it possible that your predictions/estimations about the active crossover system dB output at each of the 3 way speaker drivers resulting in a skewed frequency response over the speakers' total dB output spectrum are not what is representative of what occurs at the ear?

Is this topic worthy of a dedicated thread?
Can we meaningfully discuss this without hard data and real measurements?
Can we estimate stuff and come to meaningful results regarding the varying total dB output dependent on volume settings versus the frequency response changes due to varying amp sizes?

I don't think we can but I'm really interested to see what others have to say about this issue of varying amplifier sizes used in a active crossover system or a bi-amp'd system.

 

[DonH56]

Amplifier power need not be the same for all drivers, and generally is not, but net gain should be. At least for a conventional speaker system that assumes constant gain for all frequencies, such as a speaker designed to be driven by a single amplifier. If you utilize the high/low terminals for bi-amping then the effective gain from preamp through crossover (if separate) to speaker terminals should be the same in that case. This can be achieved by matching amplifier gains, providing gain control before the amplifiers, or both. A simple passive control before the amplifier is usually enough to match channel gains. These days processors will usually include channel trims to match effective gain.

If the speaker has no crossovers before the drivers then it is up to the system designer to ensure flat frequency response to compensate various driver/enclosure factors that can result in varying signal levels (and thus gain) for flat frequency response.

As @Buckeye Amps said earlier, it is important to avoid confusing gain and power output. A 10 W and 1000 W amp may have different gains so they achieve rated output with the same input signal, or not. You have to match the gain to the drivers (and crossover if present) to obtain flat frequency response for the listener(s).

 

[Doodski]

Amplifier power need not be the same for all drivers, and generally is not, but net gain should be. At least for a conventional speaker system that assumes constant gain for all frequencies, such as a speaker designed to be driven by a single amplifier. If you utilize the high/low terminals for bi-amping then the effective gain from preamp through crossover (if separate) to speaker terminals should be the same in that case. This can be achieved by matching amplifier gains, providing gain control before the amplifiers, or both. A simple passive control before the amplifier is usually enough to match channel gains. These days processors will usually include channel trims to match effective gain.

If the speaker has no crossovers before the drivers then it is up to the system designer to ensure flat frequency response to compensate various driver/enclosure factors that can result in varying signal levels (and thus gain) for flat frequency response.

As @Buckeye Amps said earlier, it is important to avoid confusing gain and power output. A 10 W and 1000 W amp may have different gains so they achieve rated output with the same input signal, or not. You have to match the gain to the drivers (and crossover if present) to obtain flat frequency response for the listener(s).

OK. I'm out to lunch on the gain requirements and I see the error of my ways now. Thank you @DonH56. It took your explanation to make it click even though it was right in front of me.

There is still the question in my mind of translating the gain(s) and amp(s) output power to dB SPL and the effect @ the ear. How noticeable are the variations of the gain(s) and output power to each driver going to be when analyzed in dB SPL, hearing sensitivity and frequency response? A person almost needs an acoustician for this stuff.

 

[hwest]

I don't think I was telling you it is imaginary.


When you say you do measurements - what have you measured as different between bi-amped, and not bi-amped

I don't think I was telling you it is imaginary.


When you say you do measurements - what have you measured as different between bi-amped, and not bi-amped?

It seems like I don't have your ear and you're not hearing what I'm saying so we can just leave it at we agree to disagree. Just the mere fact that I can act on speakers individually using filtering or anything I want over and above how the passive crossover is impacting the sound individually is proving to be of noticeable value to me, so let's just leave it at that. Anyone who may believe this can talk to me about it, no point in discussing it further with anyone that hasn't tried it with a setup specific to what I'm running as it could be much different, too many factors come into play for you to demand that I'm not gaining anything because you're wrong there. It's a bit arrogant to suggest you are sitting in front of my system and telling me what I'm hearing by the way, when you're not. -Thanks.

 

[Doodski]

It seems like I don't have your ear and you're not hearing what I'm saying so we can just leave it at we agree to disagree. Just the mere fact that I can act on speakers individually using filtering or anything I want over and above how the passive crossover is impacting the sound individual is proving to be of noticeable value to me, so let's just leave it at that. Anyone who may believe this can talk to me about it, no point in discussing it further with anyone that hasn't tried it with a setup specific to what I'm running as it could be much different, too many factors come into play for you to demand that I'm not gaining anything because you're wrong there. -Thanks.

Are you following my recent posts? What you are detailing is about what I am explaining and asking about in the terms of what is a noticeable effect in use as opposed to theoretical chatter. I'm of the opinion that yes a PEQ can achieve similar or near identical frequency response changes as bi-amping or even an active crossover setup and that is what @antcollinet is stating I think. The difference though in my opinion is that there are gains to be had by removing the passive crossovers, using a direct connection from the amp(s) to the drivers (Excepting the use of a blocking capacitor on tweeters.) and eliminating all those inductive and capacitive reactances that where in the power amplifier(s) output signal path before. That should provide some benefits. Whether they can be appreciable is another question. We are picking it apart one thing at a time and my intention is to iron out details in my mind and also to determine my future approach @ ASR regarding what I advise people when discussing bi-amping and active crossover systems. I want to make sure I am on the same page as the advanced experts here @ ASR and do not provide conflicting information.

 

[hwest]

Are you following my recent posts? What you are detailing is about what I am explaining and asking about in the terms of what is a noticeable effect in use as opposed to theoretical chatter. I'm of the opinion that yes a PEQ can achieve similar or near identical frequency response changes as bi-amping or even an active crossover setup and that is what @antcollinet is stating I think. The difference though in my opinion is that there are gains to be had by removing the passive crossovers, using a direct connection from the amp(s) to the drivers (Excepting the use of a blocking capacitor on tweeters.) and eliminating all those inductive and capacitive reactances that where in the power amplifier(s) output signal path before. That should provide some benefits. Whether they can be appreciable is another question. We are picking it apart one thing at a time and my intention is to iron out details in my mind and also to determine my future approach @ ASR regarding what I advise people when discussing bi-amping and active crossover systems. I want to make sure I am on the same page as the advanced experts here @ ASR and do not provide conflicting information.

I am hearing you but I'm also hearing my system. -haha but I know exactly what you're saying. When I can act on settings/filters indecently for the highs from the bass and then mix those together to come up with better sound because I have the ability to adjust those differently and independently then I'm saying I can get more of the sound 'I' like than having them all work from one setting out of my Preprocessor. It's noticeable and I think it would be noticeable to anyone.

 

[Doodski]

I am hearing you but I'm also hearing my system. -haha but I know exactly what you're saying

LoL... That's what I like about you... Get to the gear, keep it simple and use what actually sounds different/better to you. In my case I don't have the luxury of the KISS concept simplicity because I am expected due to having enough electronics knowledge to be dangerous must refine and hone my skills whenever possible to maintain a standard. Standards are everything.

 

[hwest]

LoL... That's what I like about you... Get to the gear, keep it simple and use what actually sounds different/better to you. In my case I don't have the luxury of the KISS concept simplicity because I am expected due to having enough electronics knowledge to be dangerous must refine and hone my skills whenever possible to maintain a standard. Standards are everything.

Haha, yeah I think that's me in a nutshell, I have listened to soo many configurations, systems from Lyndorf to Trinnov's, KEF's, Revel's, Totem acoustics, Raidho D's, Sonus, and a mixture of every different type of AMP trying to qualify myself as a critical listener. It has been tough and has taken many years but I think I know what I'm hearing now after 5 years of this stuff I'm eyeing up a McIntosh AMP next and a Hi Fi Rose 130 so let's see how that goes and as you said I'll let the gear tell the story until I educate myself more.

 

[Doodski]

Haha, yeah I think that's me in a nutshell, I have listened to soo many configurations, systems from Lyndorf to Trinnov's, KEF's, Revel's, Totem acoustics, Raidho D's, Sonus, and a mixture of every different type of AMP trying to qualify myself as a critical listener. It has been tough and has taken many years but I think I know what I'm hearing now after 5 years of this stuff I'm eyeing up a McIntosh AMP next and a Hi Fi Rose 130 so let's see how that goes and as you said I'll let the gear tell the story until I educate myself more.

You are very fortunate in that you get to use and own such a amazing variety of good gear. Very fortunate indeed. I acquired the majority of my gear experience from working in the industry in various capacities but I never had the higher upper end gear @ hand. It was ~from low end up to lower high end gear. But in quantity... Lotsa quantity of assorted models. Like @ the least for sure several thousands of them.

 

[DonH56]

OK. I'm out to lunch on the gain requirements and I see the error of my ways now. Thank you @DonH56. It took your explanation to make it click even though it was right in front of me.

NP

There is still the question in my mind of translating the gain(s) and amp(s) output power to dB SPL and the effect @ the ear. How noticeable are the variations of the gain(s) and output power to each driver going to be when analyzed in dB SPL, hearing sensitivity and frequency response? A person almost needs an acoustician for this stuff.

You can look at an online calculator to assess SPL vs. input power for a given loudspeaker sensitivity, listening distance, and placement with respect to walls (boundaries). But you don't even really need that for this. You can ignore loudness curves for an initial approximation, and for a typical speaker with reasonably flat response just assume the same power input at any frequency leads to the same output SPL. That is, if the speaker has flat frequency response, and is rated for 90 dB/W/m SPL, than for 1 W input at any frequency the sound level will be 90 dB when you are 1 m from the speaker. The level will fall off with distance at a rate determined by the speaker's directivity (dispersion pattern) and your room's size and treatments etc. You can ignore that too, though usually the fall-off is greater at higher frequencies than lower frequencies, but you are asking for a relative comparison between a single amp and multiple amps split across frequency bands.

Just think about 1 W at any frequency producing 90 dB at 1 m from your speaker. This is very simplistic but good enough for a quick hand-waving analysis. Now if you use two amps and they are identical, then the signal producing 1 W at 100 Hz or 10 kHz should be the same. If the amps are different, you need to determine their gain, and decide if you need to adjust their levels. This is where it gets complicated and requires some math.

The parameter most likely to be specified are input sensitivity and power output, which determine the gain of the amp (unless you get one of those that actually lists gain as well). Looking at an example:

Amp A = 100 W into 8 ohms with 1 V input
Amp B = 25 W into 8 ohms with 1 V input

Gain in V/V is Vout/Vin. Vin is specified as 1 V (rms) and since power output Pout = V^2 / R then Vout = sqrt(Pout * R) where R = 8 ohms

Thus Amp A gain = 28.28 V/V (29 dB) and Amp B gain = 14.97 V/V (23 dB). Since 1 V is a common sensitivity spec, reflecting a typical 1 Vrms output of many consumer products, the amps have different gains to achieve full output power from 1 V input. Note 6 dB is a pretty large difference, so if you put the same input level into both amps, the smaller amp will be 6 dB quieter -- until it clips. That is likely the "high" amp and likely does not need as much power, but you do not want the lower mids and bass to be that much louder than the upper mids and highs, either.

To be at the same level you'll need to add 6 dB attenuation before the 100 W ("bass") amp. Either add a series attenuator of 6 dB, turn the level control down 6 dB, or adjust the trims or channel levels in your preamp or processor to align the bass and treble gains (-6/0, -3/3, etc. in dB). Then 1 V into each amp channel will produce 25 W, though at the amps' inputs there will be 1 V into the 25 W amp and only 0.5 V into the 100 W amp's input connectors. When actually using the system, loudness curves say the bass will be much higher (10~30 dB) in level than the treble, so you may not lose power by aligning the gains. That is, when the output is 2 V, the bass amp will get 1 V and drive to 100 W, and likely the tweeter amp is still getting only a fraction of a volt because higher signals sound louder to us and thus require less signal (power).

Since "passive" bi-amping using an AVR sends the same full-range signal to both amplifiers, i.e. no crossover inside the AVR in this case, you must use identical amps, or attenuate he amp with higher gain. Attenuation fixes the level problem, but since both amps have the same signal, you don't gain anything by using a low- and high-powered amp for highs and lows because the input signal is the same from the AVR, there is no frequency splitting to let lows be louder than highs without clipping the AVR's output. Trinnov and other high-end processors allow you to set crossovers inside the box so you could use different amps. But it's a lot of effort for generally minimal if any gains.

As for audibility, I have usually said 1 dB change is not really noticeable when changing the volume, but in this case a fraction of a dB can be audible since it is applied to a very broad bandwidth (the range each amp is covering). For this, I would use the listening test criteria of 0.1 dB or less between amp channels to avoid perceptible changes in frequency response. And note changes can be good or bad; many people prefer non-flat response, and adjusting the response to account for room response and preference is perfectly valid though may not be desirable from the standpoint of altering what the artist intended for you to hear.

Again, all my handwaving, YMMV - Don

 

[antcollinet]

I'm onboard with what you say and it's been a nagging question for me for ~31 years since I built my first active crossover speaker system.
I have questioned this amplifier power balance between the drivers and resulting frequency response non-linearity issue associated with for example a 3-way active crossover system using the 3 amps of sizes ranging from:
- 60 W/ch amp for the KEF Reference Series tweeters.
- 100 W/ch amp for the Altec Lansing high efficiency midrange tuned horns.
- 250 W/ch amp for the KEF woofers in a transmission line cabinet.

When the system was operational for several+ years @ home I was preoccupied with my techy service work and I never had the extra time or the want to transport my always in use test gear to my home so that I could meter the tri-amplified active crossover system to see what was occurring and to see if there was clipping on one of the amps when the system was used more aggressively which occurred fairly often.

I was not using a calibrated mic with software as we have today to calibrate the system. The tuning was all done by ear.
I have a propensity for setting a PEQ or tone controls to unusual levels due to what sounds good to my ears and so I'm not so sure if I would go with a mic calibration method anyway.
I used a pink noise calibration method with a spectrum analyzer and calibrated mic on a previously owned passive crossover type system and the result sounded horrible although admittedly very sharp, detailed and clear sounding. I was not sure if that could have been deemed an accurate sound. I was therefore not interested in using that method on my tri-amp'd active crossover system.

I did for the sake of personal interest perform active crossover system amplifier power output calculations/estimations when I studied electron flow principles and when the math operations where fresh in my mind. The figures indicated the amplifier power output levels varied considerably from driver to driver in a standard driver configuration; meaning not using horns for midrange. Using the Altec Lansing horns and compression drivers for the midrange drivers as I did would make for less power required than required for the KEF midrange driver that I had used previously. So with the use of high efficiency horns, transmission line cabinet, and varying sizes of amplifiers one would think there would be severe imbalances in the dB output of each driver causing a very poor balance between the drivers and making for some very narrow range of operation where the system would sound good. Otherwise the frequency response outside of that sweet spot would be abysmal.

The sound quality across the volume settings ranging from (Not low.) a medium to high dB output was very enjoyable and there was no need to tweak the bass and treble controls or adjust the active crossover settings.

So regarding the topic @ this present time I am reacting on lived experience, some memory of the actual science/maths and estimations that I make up in my mind.
Is it possible that your predictions/estimations about the active crossover system dB output at each of the 3 way speaker drivers resulting in a skewed frequency response over the speakers' total dB output spectrum are not what is representative of what occurs at the ear?

Is this topic worthy of a dedicated thread?
Can we meaningfully discuss this without hard data and real measurements?
Can we estimate stuff and come to meaningful results regarding the varying total dB output dependent on volume settings versus the frequency response changes due to varying amp sizes?

I don't think we can but I'm really interested to see what others have to say about this issue of varying amplifier sizes used in a active crossover system or a bi-amp'd system.

Sorry to answer all that with one or two lines - but again you seem to be mixing up power capability and gain.

If you have two amps - one rated 100W and one rated 1000W, but both with gain 20dB

Then they will both output the same power and SPL (Up to 100W after which the smaller amp will clip) into the same load with the same input voltage signal - It is gain that is important for frequency response, not power rating of the amp.

 

[antcollinet]

The difference though in my opinion is that there are gains to be had by removing the passive crossovers

Exactly - as long as the passive crossovers are left in place then there is no audible benefit to bi amping.

Even when removed, the only benefit is you can implement a more accurate crossover in DSP. There is no further benefit in adjusting overall FR compared with using PEQ and a passive crossover.

 

[Doodski]

NP


You can look at an online calculator to assess SPL vs. input power for a given loudspeaker sensitivity, listening distance, and placement with respect to walls (boundaries). But you don't even really need that for this. You can ignore loudness curves for an initial approximation, and for a typical speaker with reasonably flat response just assume the same power input at any frequency leads to the same output SPL. That is, if the speaker has flat frequency response, and is rated for 90 dB/W/m SPL, than for 1 W input at any frequency the sound level will be 90 dB when you are 1 m from the speaker. The level will fall off with distance at a rate determined by the speaker's directivity (dispersion pattern) and your room's size and treatments etc. You can ignore that too, though usually the fall-off is greater at higher frequencies than lower frequencies, but you are asking for a relative comparison between a single amp and multiple amps split across frequency bands.

Just think about 1 W at any frequency producing 90 dB at 1 m from your speaker. This is very simplistic but good enough for a quick hand-waving analysis. Now if you use two amps and they are identical, then the signal producing 1 W at 100 Hz or 10 kHz should be the same. If the amps are different, you need to determine their gain, and decide if you need to adjust their levels. This is where it gets complicated and requires some math.

The parameter most likely to be specified are input sensitivity and power output, which determine the gain of the amp (unless you get one of those that actually lists gain as well). Looking at an example:

Amp A = 100 W into 8 ohms with 1 V input
Amp B = 25 W into 8 ohms with 1 V input

Gain in V/V is Vout/Vin. Vin is specified as 1 V (rms) and since power output Pout = V^2 / R then Vout = sqrt(Pout * R) where R = 8 ohms

Thus Amp A gain = 28.28 V/V (29 dB) and Amp B gain = 14.97 V/V (23 dB). Since 1 V is a common sensitivity spec, reflecting a typical 1 Vrms output of many consumer products, the amps have different gains to achieve full output power from 1 V input. Note 6 dB is a pretty large difference, so if you put the same input level into both amps, the smaller amp will be 6 dB quieter -- until it clips. That is likely the "high" amp and likely does not need as much power, but you do not want the lower mids and bass to be that much louder than the upper mids and highs, either.

To be at the same level you'll need to add 6 dB attenuation before the 100 W ("bass") amp. Either add a series attenuator of 6 dB, turn the level control down 6 dB, or adjust the trims or channel levels in your preamp or processor to align the bass and treble gains (-6/0, -3/3, etc. in dB). Then 1 V into each amp channel will produce 25 W, though at the amps' inputs there will be 1 V into the 25 W amp and only 0.5 V into the 100 W amp's input connectors. When actually using the system, loudness curves say the bass will be much higher (10~30 dB) in level than the treble, so you may not lose power by aligning the gains. That is, when the output is 2 V, the bass amp will get 1 V and drive to 100 W, and likely the tweeter amp is still getting only a fraction of a volt because higher signals sound louder to us and thus require less signal (power).

Since "passive" bi-amping using an AVR sends the same full-range signal to both amplifiers, i.e. no crossover inside the AVR in this case, you must use identical amps, or attenuate he amp with higher gain. Attenuation fixes the level problem, but since both amps have the same signal, you don't gain anything by using a low- and high-powered amp for highs and lows because the input signal is the same from the AVR, there is no frequency splitting to let lows be louder than highs without clipping the AVR's output. Trinnov and other high-end processors allow you to set crossovers inside the box so you could use different amps. But it's a lot of effort for generally minimal if any gains.

As for audibility, I have usually said 1 dB change is not really noticeable when changing the volume, but in this case a fraction of a dB can be audible since it is applied to a very broad bandwidth (the range each amp is covering). For this, I would use the listening test criteria of 0.1 dB or less between amp channels to avoid perceptible changes in frequency response. And note changes can be good or bad; many people prefer non-flat response, and adjusting the response to account for room response and preference is perfectly valid though may not be desirable from the standpoint of altering what the artist intended for you to hear.

Again, all my handwaving, YMMV - Don

Alrighty then... This is very well detailed information set out right in front of me very well. Thank you very much @DonH56 for putting this together and taking the time out of your busy schedule to simplify the operations so well. It makes a difference and it makes sense to me. This sort of stuff is not something I have used in application nor was it broken down much in my electronics studies many years ago. My studies seemed to be raw physics studies with little to no system analysis. I'll bookmark this for my ASR folder so I may refer to this in the future. Thank you again.

 

[Doodski]

Sorry to answer all that with one or two lines - but again you seem to be mixing up power capability and gain.

I was definitely mixing up power output, input sensitivity and gain into something piece meal and incorrect. I have never been very proficient at this stuff but it is time to iron out the details and get it together so I am not fudging stuff anymore.

If you have two amps - one rated 100W and one rated 1000W, but both with gain 20dB

Then they will both output the same power and SPL (Up to 100W after which the smaller amp will clip) into the same load with the same input voltage signal - It is gain that is important for frequency response, not power rating of the amp.

That is such a great example I am tickled. Excellent example and it makes for a really good rule of operation. Thank yoouuuu! I am setting this into the bookmarks so I can link peeps to it in the future for reference. Great stuff!

 

[MaxwellsEq]

To take it to extremes, you could have a 1000W amplifier, a 100W amplifier, a 1W amplifier and a 0.01W amplifier all with a voltage gain of 25. There is no link between wattage deliverability and gain.

MM preamplifiers have gains of c 100 and MC preamplifiers have a gain of c 1000. The reason the gain is different for the same line-level voltage output (e.g. 1V) is because the MC source has a much lower output (c 20dB quieter).

 

[Doodski]

MM preamplifiers have gains of c 100 and MC preamplifiers have a gain of c 1000. The reason the gain is different for the same line-level voltage output (e.g. 1V) is because the MC source has a much lower output (c 20dB quieter).

What is "c" ?
I attempted Googling that and found no details about what it could possibly be.

Thanks in advance @MaxwellsEq.