Thanks Marc Yes, it looks like your Crown has about 3dB headroom.
Let's do that by the numbers:
Let's do that by the numbers:
- Marc measures 11.5V RMS on the test tone at his loudest volume
- The test tone is -12dBFS (full scale) or -9dB from the loudest sine wave.
- The loudest sine wave Marc's amp will need to provide is 9dB above 11.5 volts, or 32.5V RMS
- How much voltage can Marc's crown amp supply?
- Specs say 600W into 4 ohms - which means 49V RMS
- 49/32 = 1.5 or 3.5dB
Wow this is such a cool thing!!!! How have I NOT done this yet
So I just did and here we go.
I took two measurements, one was MAX I would listen to in my room and the other was a good solid listening volume.
First thing I did a little different that I am unsure if I did correctly or not was to find what exactly the impedance my Klipsch Heresy II's were at 120Hz. I did this by placing a 1k resistor in series with a low Z source and my speaker. I measured 1.25Vrms before the 1k resistor and 11.4mV after.
.0114 / 1.25 = .00912
x / (x + 1000) = .00912
x = 9.2 + .00912x
.9908x = 9.12
x = 9.2
A close enough approximation can be made by just doing the first few steps.
Anyway I noticed that the Heresy went down to 4 ohms at 440Hz, 14 ohms at 1k.........I would like to plot it out on a logarithmic chart one day to see how lumpy they are.
So I am going to use 9.2 ohms for this test.
At MAX level I measured 4V.
((4 * 2.8)^2) / 9.2 = 13.6w
My average listening position I measure 2V.
((2*2.8)^2 / 9.2 = 3.4w
I have been wanting to build something like a Tubelab SE amp, and now I think after doing this I can live with the power level of a DHT SE amp.
Fun stuff!!!!! Thanks Pano
So I just did and here we go.
I took two measurements, one was MAX I would listen to in my room and the other was a good solid listening volume.
First thing I did a little different that I am unsure if I did correctly or not was to find what exactly the impedance my Klipsch Heresy II's were at 120Hz. I did this by placing a 1k resistor in series with a low Z source and my speaker. I measured 1.25Vrms before the 1k resistor and 11.4mV after.
.0114 / 1.25 = .00912
x / (x + 1000) = .00912
x = 9.2 + .00912x
.9908x = 9.12
x = 9.2
A close enough approximation can be made by just doing the first few steps.
Anyway I noticed that the Heresy went down to 4 ohms at 440Hz, 14 ohms at 1k.........I would like to plot it out on a logarithmic chart one day to see how lumpy they are.
So I am going to use 9.2 ohms for this test.
At MAX level I measured 4V.
((4 * 2.8)^2) / 9.2 = 13.6w
My average listening position I measure 2V.
((2*2.8)^2 / 9.2 = 3.4w
I have been wanting to build something like a Tubelab SE amp, and now I think after doing this I can live with the power level of a DHT SE amp.
Fun stuff!!!!! Thanks Pano
Hey Famous. Thanks for posting your results.
You don't really need the impedance of the speaker to know how much voltage you need, the tests tells you that almost directly. I.E., if you measured 4V, then you need 12dB above that peak (16V) of 9dB above that RMS (11.3V) You want to find an amp that can deliver at least that much into a load. Or 1/2 that at your normal listening volume.
Where it starts to get tricky is that amplifiers are rarely rated in output volts, they are rated in Watts - which is too bad. So you have to figure backwards. "OK, I need an amplifier that can supply a clean 11.3V RMS into an 8 ohm load. How would that amp be rated?" Most amps are rated by power into 8 or 4 ohms. You work from there with Ohm's law. If you could measure the amp directly, that would be even better.
E.G. I need 11.3V RMS for my loudest setting. My speakers are nominally 8 ohms.
11.3V into an 8 ohm load = 16 Watts. Find an amp that can do that, or more. If your speaker load is 4 ohms, you'll need 2X the power, so find an amp rated at 32 Watts into 4 ohms.
Or just make it easy on yourself and take the voltage you got, (4V) and square it (4x4=16) and there you have your 8 ohm power rating. Have 4 ohm speakers? Just double that number (2x16=32) and there is your 4 ohm rating. Easy Peasy.
You don't really need the impedance of the speaker to know how much voltage you need, the tests tells you that almost directly. I.E., if you measured 4V, then you need 12dB above that peak (16V) of 9dB above that RMS (11.3V) You want to find an amp that can deliver at least that much into a load. Or 1/2 that at your normal listening volume.
Where it starts to get tricky is that amplifiers are rarely rated in output volts, they are rated in Watts - which is too bad. So you have to figure backwards. "OK, I need an amplifier that can supply a clean 11.3V RMS into an 8 ohm load. How would that amp be rated?" Most amps are rated by power into 8 or 4 ohms. You work from there with Ohm's law. If you could measure the amp directly, that would be even better.
E.G. I need 11.3V RMS for my loudest setting. My speakers are nominally 8 ohms.
11.3V into an 8 ohm load = 16 Watts. Find an amp that can do that, or more. If your speaker load is 4 ohms, you'll need 2X the power, so find an amp rated at 32 Watts into 4 ohms.
Or just make it easy on yourself and take the voltage you got, (4V) and square it (4x4=16) and there you have your 8 ohm power rating. Have 4 ohm speakers? Just double that number (2x16=32) and there is your 4 ohm rating. Easy Peasy.
A few years ago after getting my first tube amp, a VTA ST-120 I visited the Polk Audio speaker forum and asked if my amp would be able to drive RTiA9's or 7's adequately. Now these PA forum members claimed to be 'experts'. One told me only Parasound audio equipment was good enough to use with those speakers. Didn't specify an amp or a power rating...just the brand name. I currently have a pair of LSiM 703's which sound pretty good with my amp. The amp however is better suited for my Klipsche speakers...though the JBL L100T3's sound pretty good too.
I didn't do this test (or not a test) when the thread first started but since it has reappeared....
1.8 volts on a pair of Altec model 19's playing the loud portions of "The Meaning" by Supertramp. Very loud in room volume. Just shy of too loud. I take it that is where the measurement should be done.
Room is about 25' x 15' x 7'9"
So this equates to 3.24 watts required?
1.8 volts on a pair of Altec model 19's playing the loud portions of "The Meaning" by Supertramp. Very loud in room volume. Just shy of too loud. I take it that is where the measurement should be done.
Room is about 25' x 15' x 7'9"
So this equates to 3.24 watts required?
Another thought. How would a more dynamic recording be better in this case? The maximum comfortable volume or the preferred volume level regardless of dynamic range would provide the correct voltage for that listener, would it not?
The recording I used seems to have a fairly wide dynamic range going from a mellow, quiet intro to a loud sax solo to massed (small massed
) voices. I think it should be valid anyway.6m x 5.5m x 2.4m room. Track: Silence (Sanctuary mix) by Delirium Track 1 - CD2
I chose this track as it drove my current setup to clipping. Amp camp amp driving Curvy chang speakers.
120Hz tone: 4.97V
220Hz tone: 4.62V
So I need a 24 watts per channel amp for max listening levels. Luckily for the Amp camp, I dont listen at anywhere near those levels these days.
Thanks for the test Pano.
I chose this track as it drove my current setup to clipping. Amp camp amp driving Curvy chang speakers.
120Hz tone: 4.97V
220Hz tone: 4.62V
So I need a 24 watts per channel amp for max listening levels. Luckily for the Amp camp, I dont listen at anywhere near those levels these days.
Thanks for the test Pano.
^Thanks for your results!
A good classical recording may have 22-25dB between average and peak. So if you set the average loud, the peaks will be way up there. It's a problem.
I would guess your track is fairly dynamic, and will try to see if I have it to analyse. Which CD is it from - do you know? Remastered discs are often less dynamic than the original releases so the actual release matters. I'd be interested to analyse the track you have.
One nice thing about a DHT SE is that the clipping is benign. You can get well into clipping without noticing it. Other amps will tell you right away when you start to clip, it's hard not to hear it and it ain't pretty.
You'd be surprised. A lot of popular music is recorded with small dynamic range. As it is already loud, you don't have to turn it up much. 16dB between average and peak is common for a lot of recordings. With the loudness wars, even less.
A good classical recording may have 22-25dB between average and peak. So if you set the average loud, the peaks will be way up there. It's a problem.
I would guess your track is fairly dynamic, and will try to see if I have it to analyse. Which CD is it from - do you know? Remastered discs are often less dynamic than the original releases so the actual release matters. I'd be interested to analyse the track you have.
One nice thing about a DHT SE is that the clipping is benign. You can get well into clipping without noticing it. Other amps will tell you right away when you start to clip, it's hard not to hear it and it ain't pretty.
Can you put some screenshots on what is done. It might be possible that your converter is just converting the file name without really decoding the files.
The conversion to wav would make sense only if it really has no encoding following the conversion.
The description of your player states that it supports only:
Support format: 16bit 44.1K WAV (the same with CD ripping and file format).
Could you check which format does your encoder output ?
That could help you to answer the question.
And the last but not least, are you really keen to test your speakers using MP3, it is quite not a high quality file and won't give you good performance even after converting it to wav