what happens to the numbers

[jgstudios]

I hope this makes sense, I'm not sure if I'm phrasing this in the correct context: My Pioneer VSX-33 receiver currently has volume (db) numbers that range from -80 thru +12 db. with the receiver running 110 W per 2 Ch into 8 Ohms. I'm usually running the Amp between -15 and -35 db volume depending on the media. Classical music needs more volume to hear the really quiet parts, so -15 seems ok for me, but there are times when I'd like to crank it up more. Anything past -15 for extended time, the receiver starts getting pretty warm, and I get paranoid about clipping and messing up my speakers, so I generally use -15 as a boundary for reasonable listening. I'm planning to attach an external 2 Ch. power amp, 550 Watts per ch. into 8 ohms, to the pre-outs, do the volume numbers on the receiver still indicate anything of significance regarding the volume, and what happens to the -80 to +12 limits of the display, are the values still relevant, or do I just ignore them and raise/lower volume as I like?

More info: I've upgraded my speakers recently from some very old Sansui S1000 units - 90db 60W, to Polk rti A9 towers, 90 db 50-500 W, and a 12" sub. It is taking more to drive the polks to the volumes I enjoy, hence the power upgrade idea. The receiver never used to get hot, now it does. I thought more headroom was the solution. I don't consider the volumes I enjoy to be crazy loud; certainly not bothering my neighbors, but I do want to distinctly hear the quiet parts, and feel the more energetic parts as well. At some point I will be changing out the receiver for a proper pre-amp, and there are a few other ideas floating around which will probably gel after the big amp is in place and I've lived with it a while.

 

[ryanosaur]

Nothing really changes, as I understand it. Perhaps if I am wrong, clarification will come.

That said, what you have is significant headroom, and under the wrong circumstances, the ability to abuse and blow drivers and/or amps.

First, look towards investing in an AC Infinity Aircom T model cooling unit. I love mine. Depending on your rack, they offer front, top, or rear venting. When running Audyssey, on my unit with that off, but the thermostat display on, my Marantz got up to 113F. Usually, before adding my external amps, it would run in the mid 80s with the fan on. That's a 30 degree difference!!! With my Amps, in 2 channel stereo mode with the Eco on, and the fans on Smart, I never go above 80 right now.

Second, you should also consider a digital SPL meter. You can use a phone app, but those can be wonky. A real one will give you better readings. This will help you know what you are experiencing at your LP. If you have an 85db sensitivity (for example) you only need 1w to get 85dB at 1 M... If you sit 6'back, roughly, you should record ~79dB at your LP. Likewise, a 92dB sensitivity should yield that @ 1m, and again, be -6dB at double that distance.
If I understand it correctly, and your system is calibrated correctly, 0 is 85dB/reference level. At that setting, you may experience dynamic peaks as high as 105dB, and potentially more, depending on the music.
Going back to my examples, an 85dB sensitivity rating, hitting a 105dB peak @1m, is drawing about 128w (every +3dB requires a doubling of power) and 512w would yield 112dB @ 1m. For that 92dB example: ~21w will clear 105dB @1m, and 512w would hit 119dB @1m.

A great tool for gauging how much power you might want to add is this SPL calculator:
http://myhometheater.homestead.com/splcalculator.html

As it regards your question about the dB numbers in your volume display, those shouldn't change because of an amp... the changes would come in the form of level calibration and how hot the recording levels of your source material are.

As I started, so shall I end... Any corrections to what I said are welcome!!!! I'm still learning, myself.

Cheers!

 

[jgstudios]

Nothing really changes, as I understand it. Perhaps if I am wrong, clarification will come.

That said, what you have is significant headroom, and under the wrong circumstances, the ability to abuse and blow drivers and/or amps.

First, look towards investing in an AC Infinity Aircom T model cooling unit. I love mine. Depending on your rack, they offer front, top, or rear venting.
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OP here: OK, thanks "ryanosaur, for the tip on that AC unit. It looks excellent and quite affordable. So as far as the volume numbers, if I want it louder and approach 0, that no longer affects the receiver since the amp is carrying the load right? I have this idea that the receiver is now more like a pass-thru device for the load. If I'm normally listening at -15, is that going to be louder than before with the amp in place? I'm assuming it's not. I'm assuming it's generally the same as before. I would then naturally want to crank it up closer to 0, so I can hear the quiet parts better, perhaps -10, or maybe even -5 on the display. Now that load is flowing to the amp and the receiver would be cooler? is that correct? Also, since 0 indicates that theoretical threshold for my receiver for clipping, that would no longer happen since the amp is now offering more headroom. Then the volume db numbers, and especially 0 no longer indicate the original theoretical boundaries, how do I then determine/monitor the clipping point? Am I totally off base here?

 

[fuzz092888]

Couple things, and I admit to only skimming the OP and the response, the home calibration number is 75db from the main LP while playing the pink noise and the volume set to 0. You can calibrate to THX reference 85db, but the home standard is 75db and I've never felt the need to calibrate to 85db since that's still more than loud enough to blow your eardrums out and you can always tick the volume up past 0 anways if you really really really want to.

https://www.audioholics.com/frequent-questions/how-to-manually-level-match-speakers

The other thing is that your receiver won't necessarily get any cooler. This would require the amp section to of the receiver to shut itself off. To my knowledge, very few receivers actually offer this as an option, so I doubt it will get any cooler without a fan on top. I have fans on top of all of mine, 100,000 hour 200mm computer fans just resting on top. I'm cheap.

The extra power of the external amp won't make anything louder if you've calibrated the speakers correctly. It will just allow your speakers to be more dynamic at higher volumes. 0 isn't a threshold, if calibrated correctly, it is merely a reference point.

There is no way to monitor clipping point except with measurement gear or your ears.

I hope this makes sense, I'm not sure if I'm phrasing this in the correct context: My Pioneer VSX-33 receiver currently has volume (db) numbers that range from -80 thru +12 db. with the receiver running 110 W per 2 Ch into 8 Ohms. I'm usually running the Amp between -15 and -35 db volume depending on the media. Classical music needs more volume to hear the really quiet parts, so -15 seems ok for me, but there are times when I'd like to crank it up more. Anything past -15 for extended time, the receiver starts getting pretty warm, and I get paranoid about clipping and messing up my speakers, so I generally use -15 as a boundary for reasonable listening. I'm planning to attach an external 2 Ch. power amp, 550 Watts per ch. into 8 ohms, to the pre-outs, do the volume numbers on the receiver still indicate anything of significance regarding the volume, and what happens to the -80 to +12 limits of the display, are the values still relevant, or do I just ignore them and raise/lower volume as I like?

More info: I've upgraded my speakers recently from some very old Sansui S1000 units - 90db 60W, to Polk rti A9 towers, 90 db 50-500 W, and a 12" sub. It is taking more to drive the polks to the volumes I enjoy, hence the power upgrade idea. The receiver never used to get hot, now it does. I thought more headroom was the solution. I don't consider the volumes I enjoy to be crazy loud; certainly not bothering my neighbors, but I do want to distinctly hear the quiet parts, and feel the more energetic parts as well. At some point I will be changing out the receiver for a proper pre-amp, and there are a few other ideas floating around which will probably gel after the big amp is in place and I've lived with it a while.

Nothing really changes, as I understand it. Perhaps if I am wrong, clarification will come.

That said, what you have is significant headroom, and under the wrong circumstances, the ability to abuse and blow drivers and/or amps.

First, look towards investing in an AC Infinity Aircom T model cooling unit. I love mine. Depending on your rack, they offer front, top, or rear venting. When running Audyssey, on my unit with that off, but the thermostat display on, my Marantz got up to 113F. Usually, before adding my external amps, it would run in the mid 80s with the fan on. That's a 30 degree difference!!! With my Amps, in 2 channel stereo mode with the Eco on, and the fans on Smart, I never go above 80 right now.

Second, you should also consider a digital SPL meter. You can use a phone app, but those can be wonky. A real one will give you better readings. This will help you know what you are experiencing at your LP. If you have an 85db sensitivity (for example) you only need 1w to get 85dB at 1 M... If you sit 6'back, roughly, you should record ~79dB at your LP. Likewise, a 92dB sensitivity should yield that @ 1m, and again, be -6dB at double that distance.
If I understand it correctly, and your system is calibrated correctly, 0 is 85dB/reference level. At that setting, you may experience dynamic peaks as high as 105dB, and potentially more, depending on the music.
Going back to my examples, an 85dB sensitivity rating, hitting a 105dB peak @1m, is drawing about 128w (every +3dB requires a doubling of power) and 512w would yield 112dB @ 1m. For that 92dB example: ~21w will clear 105dB @1m, and 512w would hit 119dB @1m.

A great tool for gauging how much power you might want to add is this SPL calculator:
http://myhometheater.homestead.com/splcalculator.html

As it regards your question about the dB numbers in your volume display, those shouldn't change because of an amp... the changes would come in the form of level calibration and how hot the recording levels of your source material are.

As I started, so shall I end... Any corrections to what I said are welcome!!!! I'm still learning, myself.

Cheers!

 

[ryanosaur]

Thanks for clarifying Fuzz!

I like seeing the thermostat display... why I budgeted for that AC Infinity. Also, the original home was in a cabinet, lots of room to breathe, but no exhaust... so I have the front venting unit...
Now that it doesn’t live in that cabinet, I’m hoping to switch to the rear venting unit.
It also allows for stacking. I have my Blu-Ray on top of the fan unit.

Cheers!

 

[fuzz092888]

The only thing I don't like about those fans and what I advised my friend who got one was to put that sticky foam tape around the bottom edge of the thing. Because of the feet, you lose CFM pulling through the receiver making it less efficient. I like the look, but my electronics are mostly hidden so it's hard to jusitfy the cost. However, if yours are out in the open then a weird looking computer fan with a random wire hanging off your receiver probably wouldn't make much sense.

I've seen some rear venting units, you just also have to be sure you have fans on top of the cabinet or behind the cabinet to pull the heat out, especially if you are going to stack on top of the fan. I built an open face entertainment center with three columns of shelves and then put back panels on them and each back panel had 2-200mm fans connected to a fan controller in order to pull heat away from the components. With that much air flowing through the cabinet I almost didn't need the fan on top of the processor.

Thanks for clarifying Fuzz!

I like seeing the thermostat display... why I budgeted for that AC Infinity. Also, the original home was in a cabinet, lots of room to breathe, but no exhaust... so I have the front venting unit...
Now that it doesn’t live in that cabinet, I’m hoping to switch to the rear venting unit.
It also allows for stacking. I have my Blu-Ray on top of the fan unit.

Cheers!

 

[ryanosaur]

Very much system dependent!!! I like what you describe. Frankly, a better solution, in my book. I’m mentally designing an equipment rack that I’m envisioning using fans in a similar way.

 

[fuzz092888]

Very much system dependent!!! I like what you describe. Frankly, a better solution, in my book. I’m mentally designing an equipment rack that I’m envisioning using fans in a similar way.

not a great picture but here it is

 

[ryanosaur]

Sweet. I'm eagerly anticipating my 3s to get delivered in a month I hope (ordered end of November... but so much is relying on Dennis health and well-being, right now)!!! The sub is matching finish? Salk Rythmik?

 

[fuzz092888]

The 3's are the best speakers I've ever owned and as long as they're hanging around I'll have a hard time justifying spending money to upgrade them. I got a pretty early pair and they're one of the only pairs of speakers I've kept more than a year or two outside of my HT system. I really hope Dennis gets better, he's a true asset to the audio community and is extremely generous with his time and knowledge. I helped him out with his website years ago and got to know him a little and he's a great guy.

Custom built sub, I make all my own subs and some of the speakers. The speakers are kits, the subs I design.

Sweet. I'm eagerly anticipating my 3s to get delivered in a month I hope (ordered end of November... but so much is relying on Dennis health and well-being, right now)!!! The sub is matching finish? Salk Rythmik?

 

[ryanosaur]

I'm getting into speaker building. With my rig nearing completion, I fully recognize that I might never be able to buy a better set of speakers, assuming I find the need to upgrade. My first project is going to be building some subs with the goal of replacing the x-13s in my system (they would then move to the main room... or if what I build doesn't perform better, then those go out front. ) But then I plan on doing the speakers out front, too.
With Dennis pulling the AAs off the list, I'm a pair of speakers short for my Atmos aspirations, and am thus considering buying the kit and parts from PE and doing my own AAs per his design on Murphy Blaster. (I have a pair he did for me with the dayton tweeter.)

As for what you said about Dennis... I whole-heartily agree! My interactions with him have left me profoundly affected in a very positive way. His love for this craft and hobby, his (almost-too-)selflessness, his friendly demeanor... all have inspired me to learn and explore the DIY path. (As well as conversations with Salk, and Eric from Tekton... but Dennis pushed it WAY over the top!)

Cheers, Fuzz!

 

[GrimSurfer]

I hope this makes sense, I'm not sure if I'm phrasing this in the correct context: My Pioneer VSX-33 receiver currently has volume (db) numbers that range from -80 thru +12 db. with the receiver running 110 W per 2 Ch into 8 Ohms. I'm usually running the Amp between -15 and -35 db volume depending on the media. Classical music needs more volume to hear the really quiet parts, so -15 seems ok for me, but there are times when I'd like to crank it up more. Anything past -15 for extended time, the receiver starts getting pretty warm, and I get paranoid about clipping and messing up my speakers, so I generally use -15 as a boundary for reasonable listening. I'm planning to attach an external 2 Ch. power amp, 550 Watts per ch. into 8 ohms, to the pre-outs, do the volume numbers on the receiver still indicate anything of significance regarding the volume, and what happens to the -80 to +12 limits of the display, are the values still relevant, or do I just ignore them and raise/lower volume as I like?

More info: I've upgraded my speakers recently from some very old Sansui S1000 units - 90db 60W, to Polk rti A9 towers, 90 db 50-500 W, and a 12" sub. It is taking more to drive the polks to the volumes I enjoy, hence the power upgrade idea. The receiver never used to get hot, now it does. I thought more headroom was the solution. I don't consider the volumes I enjoy to be crazy loud; certainly not bothering my neighbors, but I do want to distinctly hear the quiet parts, and feel the more energetic parts as well. At some point I will be changing out the receiver for a proper pre-amp, and there are a few other ideas floating around which will probably gel after the big amp is in place and I've lived with it a while.

The dB volume rating isn't very accurate because sound pressure level is influenced considerably by loudspeaker sensitivit and distance between that speaker and the listener. The amp simply has no reliable way of knowing this.

The heat issue could suggest a few things...

The first is that your amp is having difficulty driving the speakers, but a 90 dB/W/m is reasonably sensitive. Although you don't mention the load, they could be far less than 8 ohms (even if they say they're 8 ohm compatable). This would put a greater stain on your amp.

AB amps usually get warmest at about 1/4-1/3 max volume. That's because this volume levels keeps the amp in Class A mode, which the amp isn't specifically designed for operating in (AB is electrically more efficient, but this mode doesn't kick in until the amp exceeds a certain threshold). But with adequate ventilation (ie not in a closed cabinet),they shouldn't get hotter than is comfortable to press a bare hand on. And they shouldn't get hot enough to trigger s thermal protection fuse or anything like that unless operating in a high (90F+) ambient environment.

WRT the amp, you don't mention whether it's power rating is Watts RMS. This is really important because peak music power can be 3-4 times more than a WRMS rating. So you could be facing a situation where the speaker load requires more consistent energy than your amp is capable of sustaining.

You also don't mention the amp's rated output for both 4 and 8 ohms loads, which can be important because that ratio can give an indication of the robustness of the amp's power supply and capacitor load.

Resolving all of this is important prior to looking for another amp based on a particular power rating.

 

[jgstudios]

Everything is 8 ohms: receiver, speakers and the forthcoming amp.
Pioneer receiver is rated at 110 watts RMS into 8 ohms for the two main channels. This is a 9.1 AVR but I'm currently just using the two main polk towers and a subwoofer. I figure 110 Watts is not realistically the case but that's what the specs say. The AVR is certainly having to work harder driving the new Polks.
The speakers are Polk Rti A9 showing 90 db sensitivity 8 ohms, and 50-500 Watts on the spec sheet, so I assume the 500 is peak power. No rating specifically for RMS on what I can find.
The Amp will be 550 Watts RMS into 2 channels & 8 ohms.
Hope this helps and thanks for your response. JG

 

[GrimSurfer]

Everything is 8 ohms: receiver, speakers and the forthcoming amp.
Pioneer receiver is rated at 110 watts RMS into 8 ohms for the two main channels. This is a 9.1 AVR but I'm currently just using the two main polk towers and a subwoofer. I figure 110 Watts is not realistically the case but that's what the specs say. The AVR is certainly having to work harder driving the new Polks.
The speakers are Polk Rti A9 showing 90 db sensitivity 8 ohms, and 50-500 Watts on the spec sheet, so I assume the 500 is peak power. No rating specifically for RMS on what I can find.
The Amp will be 550 Watts RMS into 2 channels & 8 ohms.
Hope this helps and thanks for your response. JG

Just looked at the amp's owner's manual. It doesn't specifically use the term RMS. It uses continuous with an asterisk, leading to a statement about FTC ratings. I haven't gone into the FTC ratings system, but it's possible that it's the same as RMS (which, for all its faults, is the closest thing the audio world has for a gold standard).

The BIG issuse is that your amp is not designed to drive anything lower than 6 ohms (and only when a switch is actuated),according to what is says and doesn't say in the 120 page owner's manual. At 6 ohms, it can drive two channels to 120 watts. Based on what I know and have read, this would suggest an amplifier stage that is quite current limited... perhaps because of a small power supply or limited capacitor capacity.

Polk literature is rather coy when it comes to the RTiA9's impedance. All they say is "8 ohms nominal", which isn't saying a heck of a lot. Some speaker manufacturers manuals have diagrams. Many others list minimum impedance. Shame on apolk for using neither.

Regardless... A Sound and Vision *test* said that "Impedance reaches a minimum of 4.63 ohms at 5.3 kHz and a phase angle of –34.92 degrees at 105 Hz." Now 5300 Hz is pretty much in the middle of the audible range, so your amp will likely be spending more time there (this is an oversimplification) than at sub or very high frequencies.

So the problem is in matching the amp and speakers. It's not a power issue per se. It's an issue of a set of speakers that is asking for more than an amp of limited capacity can deliver.

This isn't particular to AVR style amps, but I see it more often in consumer-level AVRs sold thru big box stores. (Cue AVR fans who will now pile on to defend their honor.)

As an aside, I have a 30 WRMS amp that has no problem driving a set of 8 ohm nominal speakers with 88 dB/W/m whose impedance dips to 3.7 ohms at around 100 Hz. The amp is a high current design and rated for 4 ohm operation. It doesn't get hot even when playing at 85-90 dB.

So it's not power, but design and design limits.

 

[VonMagnum]

Actually, once you calibrate with Audyssey, the AVR absolutely knows what the level is at your MLP. Only then is 0dB a "reference point."

Otherwise, 0dB is typically the 0 gain or "unity" point (incoming signals are not attenuated by the preamp potentiometer, but pre-amplified at the pre-amp sections full gain. Positive values, when allowed are boosted past unity (helpful when the incoming signal us very low).

Once Audyssey measures, it adjusts the scale accordingly for the Dolby 75dB pink noise reference level instead. Adjusting individual speaker levels after the fact may override the output, however.

None of that matters much if the incoming signal isn't Dolby compliant. Music almost never is (at least on purpose) and some devices may output less than others (Apple TV is often said to be 5-6dB lower than other devices, at least for some sources. I've noticed that to be the case for certain with some Atmos movies I've compared.

The point is you may have to adjust to compensate in some cases to get the output level you want, even if that means going above 0dB (My Marantz can go to +18 if need be).

Having too much power is rarely a problem. Most speakers are blown from too little power being available for the level requested (clipping, which means the sine wave signal tries to go above the maximum voltage and squashes/flattens at the top and bottom, turning it into a square wave, which speaker drivers don't like, especially tweeters where the voice coil can overheat very quickly).

A good amp has clipping protection (e.g. My Yamaha I use with my Carvers will shut off the output rather than allow a clipped signal through until the signal is safe again.)

Many AVRs have an ECO mode that can substantially reduce heat levels by turning down (or even off) amplifiers not using much or any power. The effect is inaudible on my Marantz, but the output heat is easily 15-20 degrees F cooler without an extra fan. That is the difference between slightly warm and hot to the touch here with no loss in maximum power as it self adjusts to the requested level (swapping between Eco on/off sounds identical here). YMMV.

 

[jgstudios]

OK VonMagnum, that info about calibrating with Audyssey makes sense. I have been using the built in calibration system on the Pioneer AVR. Pioneer calls it the MCACC (Multi Channel ACoustic Calibration) system. So when I connect the new amp, I'll run MCACC, and that should get me to a place where the AVRs volume db numbers should be in synch with the new amp. I hope at least in the ball park. The only issue I've had so far with it is that the users manual never specifically states how loud I should set the volume prior to running MCACC. I mentions that the test tones will be very loud when it's running, but it never says to set it to 0 or anything. Based on that, I can only assume it sets the volume to the necessary level that the calibration system needs, but I really don't know. I can say it doesn't seem that loud to me. Anybody got any input on that, is there a specific volume that should be set when running calibration systems on AVRs or does the system take care of that?

 

[VonMagnum]

I think it just set itself here with my Marantz unit (i.e. it starts low and gets louder until it hits the peak it's looking for).

 

[William Lemmerhirt]

Anybody got any input on that, is there a specific volume that should be set when running calibration systems on AVRs or does the system take care of that?

When running the Auto cal it will calibrate itself using 75db noise. On my older Onkyo, when manually running test tones, they came out at roughly 75db, and you just had to trim up/down a few numbers. My Marantz however is different. When you calibrate manually, it starts the test tone and then you raise the volume to “0”. This is where the speakers should output 75db. Depending on the speakers sensitivity, you might have to raise it up or down a few to get the spl meter to read 75. This should leave you calibrated so if you watch a film at 0mv(master volume), you’ll be listening at reference level. 85db average, with peaks up to 115. Most people don’t get close to that.

 

[VonMagnum]

When you calibrate manually, it starts the test tone and then you raise the volume to “0”.

To make that read a bit clearer, in manual to get "reference" levels, you adjust the individual speaker levels so that they each read 75dB on an SPL meter with the main/master volume set to zero while doing so. You don't touch the master again while adjusting. It stays at zero throughout. It might be better to do it in two passes though as to not get too loud signals out of the speakers the first time through (i.e. they all default to 0dB in each individual speaker and that could be MUCH louder than 75dB if the speakers are efficient (e.g. Klipsch). You might end up at -9 for each speaker or something way below 0. Less efficient speakers might need positive values.

 

[GrimSurfer]

There is a slight methodological flaw in most auto calibration set ups... they don't know the distance between the mic and the l/r speakers. So they can't determine dB at the listening point. Also, the mic is off axis.

Some calibration systems used à wired mic that is placed st the listening position. Not perfect, but much better potential for setting a reasonable dB level...