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How much amplifier power is required?
- Thread starter Willem
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And more depending on where the speakers are placed:
A monitor with a flat frequency response in free space produces up to 6 dB higher sound level when placed against a solid wall. In a corner (two walls) this gain can be 12 dB. With three boundaries (corner close to ceiling) the gain can be +18 dB. This can be particularly seen at low frequencies.
Monitor Placement - Genelec.com
To create the ideal listening experience, several aspects need to be taken into account when placing the monitors within the listening space. First, you need to identify the listening area within the space and consider where the listener will be placed in relation to the space as well as the...
www.genelec.com
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Maybe it's already been mentioned in the thread?:
Sub bass requires a lot of power. Extremely much when:..a small cabinet with deep bass would need a very powerful amplifier
Hofmann's Iron Law
three parameters that cannot all be had at the same time. They are low-bass reproduction, small (enclosure) size, and high (output) sensitivity." Hofmann stated that designers could pick two of these three parameters, but in doing so, it would compromise the third parameter.
Josef Anton Hofmann - Wikipedia
What's more. Increased listening distance and thus need for more power applies to free space and not in a normal listening room where the room functions as a reverb chamber. Anyone can test this with a SPL/ dB meter and measure at different distances in their listening room and see that it measures the same.
Provided that the dB measurement is carried out in in a normally furnished, normal sized living room, listening room and not extremely close to the speaker driver but like that from about 4 feet, 1.2 meters from the speaker and then at longer listening distances.
4 feet, 1.2 meters from the speaker: Maybe a slightly longer (or shorter) distance is needed. You have to test that out in your room with the conditions you have (combination of room reflections and attenuation due to furniture, carpets, etc. plus dispersion on speakers) , and then come to the conclusion that distance does not matter.
A free one like this is enough to test it out:
The more dynamic the music, the more power is needed. Even in the highest registers where it is sometimes said that only a few watts are needed. Nope, with extremely dynamic music, several hundred watts may be needed. Regarding that:
#20 from the thread:
Making sense of power requirements, decibels and sensitivity
Hi there! I'm creating this little thread to ask a question for what is probably a very dumb question, but I can't for the life of me figure it out. Let's say you have speakers rated for 88 dB sensitivity (2.83 V @ 1m). The speakers' maximum SPL is 112 dB. Their power rating is 40 to 120 W...
www.audiosciencereview.com
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tineared
Active Member
A few decades ago I bought a Parasound HCA-3500 that puts out 350W@8 Ohms. It's driving a pair of 6 Ohm NHT 3.3s at an 87dB sensitivity in a medium sized room.
Not once have I ever said to myself "that's more power than I need"
I enjoy listening to concerts in my house when the spirit moves me
I want to replace the amp with a Hypex NCx500 because the Parasound is huge and has become too damn heavy (80lbs) to move gracefully, but it just won't die
I'm from the Tim Taylor school of thought with regards to amplifier power
Not once have I ever said to myself "that's more power than I need"
I enjoy listening to concerts in my house when the spirit moves me
I want to replace the amp with a Hypex NCx500 because the Parasound is huge and has become too damn heavy (80lbs) to move gracefully, but it just won't die
I'm from the Tim Taylor school of thought with regards to amplifier power
Aerith Gainsborough
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Well if you say "house", I'm assuming a rather large listening space and moderate distance to the speakers.
350W may even be on the insufficient side, regarding transients, if you listen at live concert levels.
Thank you, @tineared, perhaps you need Avantgarde Acoustic Duo Horn Speakers (106db/1W/1m) or w/omega (110db/1W/1m).
For Consideration/Discussion, lets look at the Power/W of the Parasound HCA-3500/350W@8 Ohms with the Avantgarde Acoustic Duo Horn Speakers w/omega (110db/1W/1m) compared to the NHT 3.3s (87dB/1W/1m)....
- 110db (1W/1m), for 350W (at 3m, 350W would sound like 128.9db).... Avantgarde Acoustic Duo Horn Speakers w/omega (110db) & Parasound HCA-3500/350W@8 Ohms and fill an extremely large room/building but for 350W/110db/1m/1W, will easyly fill a room to 85db/@3m and requires about 0.017W* (128.9 - 85 = 43.9db, 43.9/3=14.33, 350W/2**14.33=0.017W).
- The Parasound HCA-3500 would need to be almost no Noise/THD, high SNR/db, no Masking, at this very low volume/amplifycation, wouldn't it, and that will/would include the Devices feeding/connecting to it, won't it?
- A Preamp/Closed Loop, with low Output impedance (<=0.1R, allow (Loading) Headroom), outputs 2/4/7 watts (allow (106/110/112db Listening@3m) Headroom), plus 2x Lineout for the Subs, could possablely/easyly drive these, couldn't it, for consideration?
- 107db/175W
- 104db/87.5W
- 101db/43.75W
- 98db/21.875W
- 95db/10.9375W
- 92db/5.46875W
- 89db/2.734375W
- 86db/1.3671875W.... NHT 3.3s (87dB) for 350W (at 3m, 350W would sound like 105.9db)
- in Comparison the Parasound HCA-3500/350W@8 Ohms would be like 1.8W but for 350W/87db/1m/1W, will easyly fill a room to 85db/@3m and requires about 2.792W* (105.9 - 85 = 20.9db, 20.9/3=6.97, 350W/2**6.97=2.792W)
- *Note that it is assumed that the speakers are 8ohms (nominal) and easy to drive.... for consideration
- 10R/ohm Speaker (minimum) Load, requires about 2.34W.... notice that it is not half, why, Hint.... Voltage reference is 8R, V=√(P×R)
- 8R/ohm Speaker (minimum) Load, requires about 2.792W
- 4R/ohm Speaker (minimum) Load, requires about 5.584W
- 2R/ohm Speaker (minimum) Load, requires about 11.168W
- 1R/ohm Speaker (minimum) Load, requires about 22.336W
- where using the same voltage, P=V**2/R, because we know P/R we will know the V (in this case/above, assumed to be the same), won't we?
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tineared
Active Member
Since you brought it up, I intend to bi-amp them as I have in the past. Those magnificent Tonegen 1259 woofers are capable of some serious air movement, but they're quite hungry. The HCA-3500 will feed the woofers and I have a Parasound A23+ (160W@8 Ohms) for the 6.5" Tonegen midrange and SEAS 4" upper-midrange and 1" tweeter. Good times...
tineared
Active Member
Thanks for the suggestion, but I'm quite happy with my 3.3s and also my wife. The Avantgardes would not blend well with the room's decor and I suspect would have zero WAF.
The NHTs are quite unobtrusive for a 4-way speaker with 12" woofers that weigh 123lbs each
Aerith Gainsborough
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I don't see the point.
Wattage difference is too low, you won't notice that in practice. You're basically going from 350W -> 510W per channel, assuming the tweeters/Midrange even need that kind of Wattage. Your 350W amp feeding the woofers may clip long before your midrange/tweeter amp reaches capacity as most energy in music is usually in the bass.
Remember: doubling the amp power gives you a measly +3dB SPL.
E.g.:
350W = 110dB
700W = 113dB
1400W = 116dB
2800W = 119dB
If you really want some noticeable change, you'd need to give the system 3KW+ per channel, which would result in +9dB.
Though it begs the question whether you speakers (or your ears) would be able to handle that much power.
As you can see: amp power demands get ridiculous very, very quickly. Much easier to just accept some inaudibly clipping transients.
Thank you, @tineared, considerations for an Amplifyers Speaker Load, especially for 1/2/4R (even 8R) (minimum) Speaker Load....
- V/Voltage Invariant/Independent.... that is, regardless of Speaker R/Load, that the V does not drupe/sag, so that the Speaker sees a Constant Voltage Source.
- I/Current no Limit.... that is, regardless of Speaker R/Load, that the Amps I/Current is not Limited and the necessary/required I/Current is (instantaneously/no Lag) delivered to the Speaker.
- Output Impedance.... that is, for the above to work well, the Amps Output Impedance must be at least 1/10th (1 Decade, preferablely more/lower) lower than the Speakers (minimum) Impedance.
- Note that Capacitive Speaker Loads are another matter, aren't they? It would be nice to read yours or others discernment of Capacitive Speaker Loads, please do so, thank you :=)
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Sokel
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Nope.
Seriously now, a personal calculation for the reference level gets reasonable results, for as with classical for example peaks are everything.
Same with rock as I suspect, as the measly 3db is what sometimes separates the chest punch to meh...
Power is easy and dirt cheap these days.
Really depends on the material indeed.Nope.
Seriously now, a personal calculation for the reference level gets reasonable results, for as with classical for example peaks are everything.
Same with rock as I suspect, as the measly 3db is what sometimes separates the chest punch to meh...
Power is easy and dirt cheap these days.
Manufacturers: average power is usually 1/5 of peak power (crest factor).
Drum'n'Bass musicians: are you fucking kidding me?
tineared
Active Member
I agree that any improvement will be minimal, but it costs me nothing to implement as I already have all the gear so there really is no down side. The system is not currently underpowered as it plays far louder than I need (>110dB) or want and I never hear any indication of clipping.
Thank you, @Sokel, intrigueing, is this to do with Amplifyer and/or Speaker considerations, other than Amplifyer Power (as Titled), or are you suggesting that Amplifyer Power is everything?
Re reference level.... if you do not mind, could you clarify what 'reference level' means, thank you :=)
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Sokel
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I would take mains, control room monitors as a good example.
You can take a look at the power they are using to achieve the desired. Smaller active monitors as well.
About reference level, the norm is the THX standard which requires 85dB SPL with 20dB of headroom with reasonable low distortion, at least, with the THX Certified Dominus performance reaching 120dB SPL.
The above is not written to stone of course and we all must take take of our hearing, follow the instructions, etc.
Thank you, @Sokel, Ah, re reference level/calculation....
- a good approach is that your Amp/Speaker combination, with reasonable low Distortion/without Cliping/for Listening@3m, needs to be able to deliver 120dB SPL, rather than 110db SPL, to ensure that Dynamic Peaks/Chest Punch are delivered without meh, is that correct?
- If yes, for a 110db SPL Speaker and Listening@3m, a 45W Amplifyer is needed to deliver 120db SPL, Dynamic Peaks/Chest Punch, is that correct?
- For a 87db SPL Speaker and Listening@3m, a 9000W Amplifyer is needed to deliver 120db SPL, is that correct?
- For a 87db SPL Speaker and Listening@2m, a 4000W Amplifyer is needed to deliver 120db SPL, is that correct?
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Reference level is defined in the Dolby / THX / DTS standards, as a signal at -20dbFS being reproduced at the listening spot at 85db (theatre standard) or 75db (domestic / home standard).
Movies are always recorded to this standard - which then allows for proper calibration of listening spaces / theatres to accurately reproduce the recording as per the mastering engineers wishes.
As the reference signal is at -20db and the digital recording maximum is 0db, to reproduce the entire gamut of dynamic range, including peaks, you need 20db above reference as your peak capability.
So in a home you need 95db, and in a movie theatre you need 105db
Note that the reference level for the Low Frequency Effects channel (sometimes erroneously called the "sub" channel) - is 10 db higher - so base level in home for LFE is 85db and peak 105db, and for theatres 95db with peak 115db.
Thank you, @dlaloum, Yes, your Amp/Speaker combination needs to be able to deliver at least 20db above your Listening Level (75/85/95/105db/your choice, for your distance from the Speakers), to ensure that Dynamic Peaks/Chest Punch are delivered without meh and/or cliping :=)
- How do you workout 20db/Listening Headroom, perhaps this is reasonable (let me know?).... 87dB speakers, 3m/Listening Position, 85db Listening Level
- Amp, to easyly fill a room to 85db@3m requires about 2.792W (3W amp can do this, can't it?)
- 105db@3m, 20db/Listening Headroom, requires about 285W (300W amp can do this, can't it? For @tineared's amp/350W/8R, he knows exactly what he is doing, doesn't he, and hopefully his amp will cover the Speakers Impedance below 8R (amp/speaker specs will/should reveal)?
- to clarify, use the SPL Calculator
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Aerith Gainsborough
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Depends on the speaker, really. Though 120dB is kinda whacko.
My Arias have an average sensitivity of 89.5dB @ 1m.
Reaching 120dB clip free transient peak at 1m ! would (theoretically) need 300W of power, if we assume 2 speakers = +3dB at the same wattage.
Calculated with: https://mehlau.net/audio/spl/ (close to walls, 117dB target, to account for a second speaker's gain).
I don't think the Arias could handle that, according to Focal, they are rated at 120W. That is in a nearfield setup at 1m.
If we increase the distance to the typical 3m couch listening, we're at 2500W for transients. Yeah ... lol. Not going to happen.
Using the more realistic THX theater 85dB average, 105dB transient peak reference: Same calculations per above (103dB target to account for second speaker) but now a "puny" 100W amp is suddenly sufficient. This is with a distance of 3 meters.
Please take into account that SPL decay in the closed room is different from the free space. In free space, it is -6dB with doubling the distance. But in a furnished room, it would be typically only -3dB.
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