BoredErica
Addicted to Fun and Learning
Thanks for your time in advance for whatever you can answer.
1. Does Amir do any measurement for speaker amps that explains how much hiss I can expect to hear from a passive speaker when playing nothing? Do I look at power vs distortion and look at THD% for 50mW? I look at the graph below me an I have no idea how loud hiss would be coming the speaker. Will it be dead silent in a special room isolated from outside noises? Is this level of performance we can expect from $500 speaker amps?
2. What is a good speaker power calculator? I'm using this (http://www.hometheaterengineering.com/splcalculator.html).
3. I used a cheap $30 dBa meter from Amazon and pointed it at a speaker while playing music from where my ear normally would be. It read about 65db. Let's add 5db to it in case for peaks I guess, and another 5db if I need to crank up the volume while I walk around the room. 5db more for EQ leeway. 80db. If I sit 2ft from the speaker, for a speaker like LS50 Meta with sensitivity of 85db (2.83V/1m), the calculator says I only need 0.2w. I understand sitting close to a speaker and not listening very loudly puts a huge load off the amp's shoulders, but isn't that insanely low? Like I-could-drive-this-off-a-headphone-amp-maybe low? I tested a Neumann Kh80 and it drew 8.3w constantly both idle and while playing something and the LS50 is supposed to be an inefficient speaker.
4. According to the chart below, the impedance of the speaker can swing all the way up to almost 30ohms. How can we be sure an amp can deliver enough power at 30ohms if the amp reviews test 4 and 8ohms? Is it really just too easy to power them at that point, so there's no point in testing that high of impedance?
5. I read for headphones that we want output impedance of an amp to be less than 1/30th of the nominal impedance of the headphones. What about speakers? Headphones go to 300ohms, even more so a 30th of that is no big deal. Speakers seem to go very low so a 30th of that is a much smaller number.
6. There is interference coming from my computer that I can hear from my Rokit 6 g2. As I move my mouse I can hear the noise change. If I start a game it gets louder and different. I think it's ground loop. I have a Neumann KH80 here. The power connector to socket is 2 prong. I don't seem to hear this interference on this speaker. From Sound on Sound's article:
Is this speaker just somehow immune to ground loops?
7. Is my assessment correct? To kill ground loops, DAC needs to have balanced output, and amp needs to have balanced input. Amp doesn't need balanced output to the speaker though. If the speaker is powered, it needs to have balanced input.
8. For Rythmik F12, in order to hook up balanced speakers I have to use an audio interface like Motu Ultralite Mk5 because the sub lacks internal crossover/balanced inputs, correct?
9. The speaker preference rating is for mid/far field listening. I only listen 19-24in away. Do I just look at CEA2034 and Early Reflections graphs and try to come to my own conclusions? The estimated in-room response's gotta be for mid/far field, so it's useless. Right?
10. Overall it seems headphone amps/dacs have improved significantly in the past 5 years. How much have speakers/headphones/speaker amps improved?
1. Does Amir do any measurement for speaker amps that explains how much hiss I can expect to hear from a passive speaker when playing nothing? Do I look at power vs distortion and look at THD% for 50mW? I look at the graph below me an I have no idea how loud hiss would be coming the speaker. Will it be dead silent in a special room isolated from outside noises? Is this level of performance we can expect from $500 speaker amps?
2. What is a good speaker power calculator? I'm using this (http://www.hometheaterengineering.com/splcalculator.html).
3. I used a cheap $30 dBa meter from Amazon and pointed it at a speaker while playing music from where my ear normally would be. It read about 65db. Let's add 5db to it in case for peaks I guess, and another 5db if I need to crank up the volume while I walk around the room. 5db more for EQ leeway. 80db. If I sit 2ft from the speaker, for a speaker like LS50 Meta with sensitivity of 85db (2.83V/1m), the calculator says I only need 0.2w. I understand sitting close to a speaker and not listening very loudly puts a huge load off the amp's shoulders, but isn't that insanely low? Like I-could-drive-this-off-a-headphone-amp-maybe low? I tested a Neumann Kh80 and it drew 8.3w constantly both idle and while playing something and the LS50 is supposed to be an inefficient speaker.
4. According to the chart below, the impedance of the speaker can swing all the way up to almost 30ohms. How can we be sure an amp can deliver enough power at 30ohms if the amp reviews test 4 and 8ohms? Is it really just too easy to power them at that point, so there's no point in testing that high of impedance?
5. I read for headphones that we want output impedance of an amp to be less than 1/30th of the nominal impedance of the headphones. What about speakers? Headphones go to 300ohms, even more so a 30th of that is no big deal. Speakers seem to go very low so a 30th of that is a much smaller number.
6. There is interference coming from my computer that I can hear from my Rokit 6 g2. As I move my mouse I can hear the noise change. If I start a game it gets louder and different. I think it's ground loop. I have a Neumann KH80 here. The power connector to socket is 2 prong. I don't seem to hear this interference on this speaker. From Sound on Sound's article:
The major benefit of being a Class-II device is that there is absolutely no chance of suffering ground-loop hums (or buzzes) when connecting these monitors to a computer interface, even if using unbalanced connections — and that may well be a very welcome feature for many! However, the potential downside is the possibility of having no ground reference in the audio system at all (eg. if using a laptop with a bus-powered interface), and that can reduce the effectiveness of the equipment’s RF screening to result in nasty buzzes due to external interference.
Is this speaker just somehow immune to ground loops?
7. Is my assessment correct? To kill ground loops, DAC needs to have balanced output, and amp needs to have balanced input. Amp doesn't need balanced output to the speaker though. If the speaker is powered, it needs to have balanced input.
8. For Rythmik F12, in order to hook up balanced speakers I have to use an audio interface like Motu Ultralite Mk5 because the sub lacks internal crossover/balanced inputs, correct?
9. The speaker preference rating is for mid/far field listening. I only listen 19-24in away. Do I just look at CEA2034 and Early Reflections graphs and try to come to my own conclusions? The estimated in-room response's gotta be for mid/far field, so it's useless. Right?
10. Overall it seems headphone amps/dacs have improved significantly in the past 5 years. How much have speakers/headphones/speaker amps improved?
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