More speakers, less watts?

[sigbergaudio]

Thank you, I somehow missed the 4ohm chart in Amir's review, now found it. The speakers are Emotiva T2+ and C2+, 60Hz and 80Hz crossover respectively are recommended values by SVS matching tool. Crossing mains at 80Hz, would probably reduce power requirements for mains, but might not be as accurate and directional, T2+ FR spec goes as low as 35Hz. Let me know if there are other considerations for crossing mains at 80Hz.

Your subwoofer is simply better suited than your speakers to reproduce these frequencies, and they will be happy to be relieved of them (aka play cleaner and sound better). 80hz is not directional.

 

[Persik]

In saying it won't make any difference a presumption is being made that the PSU feeding the amps is maxed out current-wise which is unlikely to be the case. The reason it won't make a huge difference is because even if it current supply was unlimited (enabling available amp power to double) you're only picking up a theoretical maximum extra 3dB headroom anyway which is nice but not game changing. Depending on how close your system is to its limits, that may not make any difference at all to the playback.



I assume you're now talking about music playback. All my calcs above are for movies.

Running in a 2 channel mode (vs. multi-channel surround sound) will increase available amplifier gain per channel by about 1.5dB as no need to de-rate available power by 30%. The problem is that music is usually mastered hotter than movies as a result of the "loudness war" that kicked off in the 1980s - search that term and you'll get the background.

These are digital music signal source levels from Wikipedia:

Service Loudness (measured in LUFS)
Spotify -13 to -15 LUFS
Apple Music -16 LUFS
Amazon Music -9 to -13 LUFS
YouTube -13 to -15 LUFS
SoundCloud -8 to -13 LUFS
Tidal -14 LUFS

The loudest movie source signal is -20 LUFS (i.e. 85dB reference) and many are lower. LUFS is Loudness Unit reference to Full Scale - full scale being 105dB.

The bottom line is that music source signals can be 5-12dB hotter than movies so you need to be careful when cranking it up. This is why Denon AVR's Dynamic EQ feature has higher adjustment settings for music to an create equal loudness curve.

Thank you, that is very helpful!
That also explains why streaming Apple Music via AirPlay sounds very loud, compared to e.g. Phono input that I had to source volume correct +12dB to sound closer, but still not as loud as Apple Music.
I’d like to set a volume limit so that the equipment is protected and kids will not accidentally crank it beyond unsafe listening levels. Do you know if volume max level setting limits amp performance in any way beyond how far it can be cranked up?

 

[Mr Wolf]

Do you know if volume max level setting limits amp performance in any way beyond how far it can be cranked up?

No, it just limits the volume setting, no form of compression is applied. I set mine at -10dB and the power on volume setting to -32dB to prevent sudden shocks as my son usually switches it off at high volumes!

 

[Head_Unit]

Highpass filters "put it back"???

Ah it's a bit hard to describe without graphics which this countryside connection is too weak for. What was shown to me is the highpass filters, while removing some total energy, actually increase the voltage swing. It's one of the side effects of the filters. So while highpass filtering can decrease the total power load on the power supply* it may not reduce the clipping at all.
*maybe. Because if you highpass filter at like 40 Hz, I'd think all you're cutting out is the occasional heavy subbass passages in movies, maybe not that much power out of an AVR. More power out of a subwoofer amp, which is trying to blast what is often a small box at very low frequencies=inefficient.

 

[sigbergaudio]

Ah it's a bit hard to describe without graphics which this countryside connection is too weak for. What was shown to me is the highpass filters, while removing some total energy, actually increase the voltage swing. It's one of the side effects of the filters. So while highpass filtering can decrease the total power load on the power supply* it may not reduce the clipping at all.
*maybe. Because if you highpass filter at like 40 Hz, I'd think all you're cutting out is the occasional heavy subbass passages in movies, maybe not that much power out of an AVR. More power out of a subwoofer amp, which is trying to blast what is often a small box at very low frequencies=inefficient.

If you cross at the more typical 80hz or higher, it's no question that the amp and loudspeakers are better off. The subwoofer (assuming it's reasonably dimensioned for the system) is designed explicitly to play deep bass, and will do so much better.

 

[Trell]

If you cross at the more typical 80hz or higher, it's no question that the amp and loudspeakers are better off. The subwoofer (assuming it's reasonably dimensioned for the system) is designed explicitly to play deep bass, and will do so much better.

Just setting a high-pass filter and not using a subwoofer can improve the sound for some speakers/monitors, at the expense of missing some lower Hz. I seem to recall that @amirm did so in at least one speaker/monitor review.

 

[Soundmixer]

As others have stated and the review shows, the power is somewhat reduced as more channels are added, but surround channels typically need less power than the main/center, and there's rarely the need for full output from all channels.

It used to be the surrounds needed less power. However, with the introduction of Atmos and X, that has changed. Now ALL channels (for the most part) are equal and should have equal power. Two movies come to mind that outline this pretty well. San Andreas in Atmos, and the first Harry Potter movie in DTS-X. San Andreas has a bunch of scenes where the surrounds and ceiling speakers are pushed full throttle along with all the other speakers. Harry Potter has a couple of scenes where full-range "whooshes" going through all of the channels with the LFE going full throttle.

 

[Soundmixer]

I discovered that, in any Dolby reference mix (old or new), the theoretical maximum is the equivalent of four speaker channels (3 front + 1 surround) being driven to 20dB peaks and the LFE channel to 30dB peaks. For broadcast/home releases (e.g. Blu-ray), these peaks are often lowered a few dB to reduce dynamic range.

This is incorrect. Ever since the introduction of Dolby Digital, both surrounds can be driven to 20db peaks, not just one. For the home, I don't reduce peaks, I reduce the overall mastering level of the mix. I may trim the bass a bit, but I do not reduce the peaks in my mixes.

 

[Trell]

It used to be the surrounds needed less power. However, with the introduction of Atmos and X, that has changed. Now ALL channels (for the most part) are equal and should have equal power. Two movies come to mind that outline this pretty well. San Andreas in Atmos, and the first Harry Potter movie in DTS-X. San Andreas has a bunch of scenes where the surrounds and ceiling speakers are pushed full throttle along with all the other speakers. Harry Potter has a couple of scenes where full-range "whooshes" going through all of the channels with the LFE going full throttle.

Multichannel music on SACD or DVD-A assumes that all speakers are "full range" since their introduction about two decades ago. With Blu-ray full range high quality sound was available for each channel.

 

[sigbergaudio]

It used to be the surrounds needed less power. However, with the introduction of Atmos and X, that has changed. Now ALL channels (for the most part) are equal and should have equal power. Two movies come to mind that outline this pretty well. San Andreas in Atmos, and the first Harry Potter movie in DTS-X. San Andreas has a bunch of scenes where the surrounds and ceiling speakers are pushed full throttle along with all the other speakers. Harry Potter has a couple of scenes where full-range "whooshes" going through all of the channels with the LFE going full throttle.

I'd say it's still not the case for most movies, and the LFE should be redirected to the subwoofer(s). Most AVRs also support setting higher crossovers for the surround channels if necessary.

 

[sigbergaudio]

Just setting a high-pass filter and not using a subwoofer can improve the sound for some speakers/monitors, at the expense of missing some lower Hz. I seem to recall that @amirm did so in at least one speaker/monitor review.

While technically correct, it's not a great solution since you're then lacking the bass that is (literally) fundamental in accurate and realistic reproduction.

 

[Trell]

While technically correct, it's not a great solution since you're then lacking the bass that is (literally) fundamental in accurate and realistic reproduction.

But it is an option when more capable speakers or subwoofers can't be accommodated for the desired listening volume.

 

[Trell]

I'd say it's still not the case for most movies, and the LFE should be redirected to the subwoofer(s). Most AVRs also support setting higher crossovers for the surround channels if necessary.

Even for multichannel SACD many recording labels are making the assumption that front LR are the best speakers in playback and thus don't use the full range capability available for the format. This is not just for lower frequencies but even the use of the center channel where on some recordings it's heavily used to not at all.

 

[JayGilb]

waay back in the day I had a 4 channel system rated at 55wpc and when I added a second pair of stereo speakers and turned the dial to A+B sound pressure in the room increased. 5 years later I bought a receiver with the same 55wpc rating from the same manufacturer and sound pressure decreased when I went to A+B and they were the same speakers. My point? good question.

Maybe the first receiver drove the B speakers with an additional set of output circuits, but the second receiver just added the B outputs in series with the A outputs ?

 

[Soundmixer]

I'd say it's still not the case for most movies, and the LFE should be redirected to the subwoofer(s). Most AVRs also support setting higher crossovers for the surround channels if necessary.

I don't let a "most case" be my foundation when it comes to immersive/surround audio. I look at the most demanding instances, with the idea the system will be able to handle all cases if it can handle that. The software should be the limitation, not the system itself.

A higher crossover on the mains means more directional information directed to the sub. That is not ideal with movie soundtracks. The sub should disappear when it is well integrated with the main speakers. The higher the crossover point, the harder it is for the sub to integrate and disappear.

 

[Soundmixer]

Multichannel music on SACD or DVD-A assumes that all speakers are "full range" since their introduction about two decades ago. With Blu-ray full range high quality sound was available for each channel.

Unfortunately, with no standards in place, neither was ever used with full range in mind for all channels (all being the keyword here). Most of the time the LFE was not used as intended, not used at all, or used full range unfiltered. Also, the center was used to isolate vocals (if used at all), and the surrounds were never used full range. For the most part, the bass was isolated to the L/F mains. We agree on this.

 

[sigbergaudio]

I don't let a "most case" be my foundation when it comes to immersive/surround audio. I look at the most demanding instances, with the idea the system will be able to handle all cases if it can handle that. The software should be the limitation, not the system itself.

A higher crossover on the mains means more directional information directed to the sub. That is not ideal with movie soundtracks. The sub should disappear when it is well integrated with the main speakers. The higher the crossover point, the harder it is for the sub to integrate and disappear.

If you have limitless money and need make no compromise, that's fine. For the rest of us, the setup will always be a compromise. For instance, many people have a mixed use system, and opting for equal speakers may mean that they get inferior main speakers for music as opposed to spending more on them compared to the surround speakers.

Depending on your room and your subwoofer placement and subwoofer quality, crossover at 100 or even higher will work fine without localisation issues.

 

[Mr Wolf]

This is incorrect. Ever since the introduction of Dolby Digital, both surrounds can be driven to 20db peaks, not just one. For the home, I don't reduce peaks, I reduce the overall mastering level of the mix. I may trim the bass a bit, but I do not reduce the peaks in my mixes.

It's very interesting to hear you say this. Are you saying the 20dB surround channel peaks are just what you do or your production company does or is it an industry standard?

I thought surround peaks were 20dB for over 20 years until I saw a YT video recently in which the head of soundtrack mixing from Sony pictures stated that they're capped at 17dB. Surprised at this statement I dug a bit deeper and found Netflix's mixing standard is channel peaks be limited to no higher than 17.7dB (and that's from a 79dB-82dB baseline, not 85dB - so max peak of 99.7dB). I then found Dolby's Atmos Mixing Studio Certification guide (available online), which in effect specifies a gold standard for an Atmos playback system, and it states that front channels must be 20dB peak capable and surrounds 17dB peak capable.

How do you reconcile these findings to what you do? What is the source of the mixing guidance/policy you are following?

 

[Soundmixer]

If you have limitless money and need make no compromise, that's fine. For the rest of us, the setup will always be a compromise. For instance, many people have a mixed use system, and opting for equal speakers may mean that they get inferior main speakers for music as opposed to spending more on them compared to the surround speakers.

This statement is nothing more than a two-channel mentality being applied to surround. All setups have compromises, you have to choose where to make them. Skimping on amp power for the surrounds and heights is IMO an unacceptable compromise. One of my immersive setups has the same speakers all the way around (except up top), and there were no compromises made - it was designed for mixed-use right from the start. If you are trying to shoehorn surround into a two-channel system, then all kinds of compromises are already made. If you know from the start your system will be mix-use, then you choose the best speakers all the way around that scale well to the room.

Depending on your room and your subwoofer placement and subwoofer quality, crossover at 100 or even higher will work fine without localisation issues.

Sorry, but this is incorrect. Unless the subwoofer is sitting directly under the main speaker, any crossover setting above 80hz will cause the sub to localize. The quality does not matter, the placement does not matter, the frequency does. Even if you place a sub in a corner, it will localize above 80hz. Test after test has shown 80hz as being the threshold of localization.

 

[Weeb Labs]

Sorry, but this is incorrect. Unless the subwoofer is sitting directly under the main speaker, any crossover setting above 80hz will cause the sub to localize. The quality does not matter, the placement does not matter, the frequency does. Even if you place a sub in a corner, it will localize above 80hz.

Based upon this study and this one, a singular subwoofer in a typical room does not become localizable until the crossover frequency reaches approximately 100-120Hz, with minimal directional cues below 200Hz.