Actually, between about 3-4 watts RMS for that measurement. Why? Because the test signal is 12dB RMS below the maximum digital PEAK level. The test signal is 9dB RMS below the loudest sine wave allowed in the recording.
9dB is 2.82X. So your measurement should be multiplied by 9dB (2.82). 1.8x2.82=5V RMS. Remember that 2.83 volts is just 1 watt into 8 ohms. Amplifiers are normally rated on sine waves, not peak.
You'll want an amp that can supply at least 5V into your speaker load. Since amplifiers are not usually rated in output volts, you'd need an RMS power output of just over 3W. That isn't much, but the tests show your loudest RMS sine would be 5 volts. Peaks would be just over 7 volts.
There is an even easier way. Just take the voltage your got on the test and square it.
1.8x1.8=3.24 That's the minimum RMS wattage rating into 8 ohms.
9dB is 2.82X. So your measurement should be multiplied by 9dB (2.82). 1.8x2.82=5V RMS. Remember that 2.83 volts is just 1 watt into 8 ohms. Amplifiers are normally rated on sine waves, not peak.
You'll want an amp that can supply at least 5V into your speaker load. Since amplifiers are not usually rated in output volts, you'd need an RMS power output of just over 3W. That isn't much, but the tests show your loudest RMS sine would be 5 volts. Peaks would be just over 7 volts.
There is an even easier way. Just take the voltage your got on the test and square it.
1.8x1.8=3.24 That's the minimum RMS wattage rating into 8 ohms.
I did the test back a while ago. With my floorstanding Snell Type C speakers, it came out that I needed about 3.4V (roughly 11.5 watts) to drive them to as loud as I could stand. Snell Type C are 4 ohms, 90dB/2.83/1m sensitivity (at 4 ohms). My weenie 6 watt per channel tube amp drives them well enough for my normal listening.
But now, I'm thinking I want to try a pair of Magnepan MMG speakers. These are also 4 ohm speakers, but are rated at only 86dB/2.83V/1m sensitivity.
A -4dB drop in sensitivity is a lot. How do I calculate the additional power I'll want/need to drive the Magnepan speakers? Do I multiply the voltage I needed before by 4dB (* 1.59)? That would mean I'd need 3.4V * 1.59 = 5.4V, which would mean about 30W per channel. Yikes! That seems like a LOT of power. All I have on hand is a Hafler P1000, which is spec'd to deliver about 55 watts per channel at 4 ohms.
Does that look right?
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But now, I'm thinking I want to try a pair of Magnepan MMG speakers. These are also 4 ohm speakers, but are rated at only 86dB/2.83V/1m sensitivity.
A -4dB drop in sensitivity is a lot. How do I calculate the additional power I'll want/need to drive the Magnepan speakers? Do I multiply the voltage I needed before by 4dB (* 1.59)? That would mean I'd need 3.4V * 1.59 = 5.4V, which would mean about 30W per channel. Yikes! That seems like a LOT of power. All I have on hand is a Hafler P1000, which is spec'd to deliver about 55 watts per channel at 4 ohms.
Does that look right?
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I used the 220Hz tone, and an inefficient speaker (my proto Omni).
Max is 4Vrms, and normally its around 1Vrms. I could easily be happy with a smaller amp.
That being said, I knowingly "over-amp" (100W/ch). I usually want the features of the bigger amp, the low impedance drive capability and more potential headroom. Probably a good thing I don't use this reasoning for buying clothes 🙂
Max is 4Vrms, and normally its around 1Vrms. I could easily be happy with a smaller amp.
That being said, I knowingly "over-amp" (100W/ch). I usually want the features of the bigger amp, the low impedance drive capability and more potential headroom. Probably a good thing I don't use this reasoning for buying clothes 🙂
Bigger power supplies, even if not fully used, often sound good. Low output impedance can also help.
As for the Maganpans, they do need power. If they are 4dB less sensitive, they'll want about 1.6X more voltage, or 2.5X the power of what you have now. Maybe more, as they play so clean you could up running them louder. Also, the are a mostly resistive load, which makes them easy to drive.
As for the Maganpans, they do need power. If they are 4dB less sensitive, they'll want about 1.6X more voltage, or 2.5X the power of what you have now. Maybe more, as they play so clean you could up running them louder. Also, the are a mostly resistive load, which makes them easy to drive.
Great work Pano!
Described this test on my blog:
MUSINGS: How much amplifier power do you really "need"? Why not test for yourself?
Described this test on my blog:
MUSINGS: How much amplifier power do you really "need"? Why not test for yourself?
Excellent! Your Blog looks great and your photos and explanation make it super clear and easy to understand. 
Maybe I should link to your blog in the first post?
Maybe I should link to your blog in the first post?
Thanks for this, it was interesting.
Result: 2.76V
Monitor Audio Bronze BX5
Room 3.3x3.2m
Volume set whilst listening to Sol Gabetta 'Prayer' CD
Result: 2.76V
Monitor Audio Bronze BX5
Room 3.3x3.2m
Volume set whilst listening to Sol Gabetta 'Prayer' CD
For the most part I really enjoy them, they seem really detailed and suit my small room. Recently though, within the last year or so, I've found high piano notes a little piercing. As I hadn't noticed it before I'm presuming it's a problem with my ears.
Just tried my office (shed in the garden) approx 3x2m
Result: 4.57V
Wharfedale Diamond 10.1
Volume set whilst listening to Sol Gabetta 'Prayer' CD
Result: 4.57V
Wharfedale Diamond 10.1
Volume set whilst listening to Sol Gabetta 'Prayer' CD
I really like Monitor Audio.
NealJ, it looks like you have small rooms. I asked recently about using a small room, and it seems you're quite happy to be using a tiny room (and fairly loud it seems 🙂 ). This inspires me to create my small sound room!
NealJ, it looks like you have small rooms. I asked recently about using a small room, and it seems you're quite happy to be using a tiny room (and fairly loud it seems 🙂 ). This inspires me to create my small sound room!
Mrcloc, yes, I have a small house with small rooms so I just to have to make the most of it. I use a Marantz PM6005 in the living room with the BX5s and use a Raspberry Pi with Digi+ hat as the transport. It suits me fine in this small room!
I don't listen at very loud volumes normally, I just pushed the volume level to more than I would ever need for the purpose of the test.
I don't listen at very loud volumes normally, I just pushed the volume level to more than I would ever need for the purpose of the test.
Thanks for this. I just did some tests, I own two pair of Totem speakers. One pair are the 4 Ohm Totem Rainmaker, the others are the 8 Ohm Kin Mini speakers.
Here are my findings:
---------------------------------
Manufacturer: Totem
Model: Totem Rainmaker
Min. Impedance: 4 Ohms (listed) - 3.8 Ohms according to Stereophile
Sensitivity: 87.5 dB/W/m
120Hz Measurement: 3.85V
---------------------------------
Manufacturer: Totem
Model: Totem Kin Mini
Min. Impedance: 8 Ohms (listed)
Sensitivity: 88 dB/W/m.
120Hz Measurement: 2.5V ~ 3V
---------------------------------
Thanks.
Here are my findings:
---------------------------------
Manufacturer: Totem
Model: Totem Rainmaker
Min. Impedance: 4 Ohms (listed) - 3.8 Ohms according to Stereophile
Sensitivity: 87.5 dB/W/m
120Hz Measurement: 3.85V
---------------------------------
Manufacturer: Totem
Model: Totem Kin Mini
Min. Impedance: 8 Ohms (listed)
Sensitivity: 88 dB/W/m.
120Hz Measurement: 2.5V ~ 3V
---------------------------------
Thanks.
Hi Pano, just found your survey and ran it for my Manzanitas.
I set the "typical" volume with the piano piece Clair de Lune which has a good mix of soft and strong. Then with the tone measured 15.5Vac at the speaker with my DMM. That is about 240W. Big family room with books shelves or big canvases on most walls and 3 metre ceiling.
Really illustrates how lossy the open baffle dipoles can be. On the other hand, the Manzanita is the only speaker I have heard that can make a piano sound like a live piano so the trade-off is worth it.
Many thanks
I set the "typical" volume with the piano piece Clair de Lune which has a good mix of soft and strong. Then with the tone measured 15.5Vac at the speaker with my DMM. That is about 240W. Big family room with books shelves or big canvases on most walls and 3 metre ceiling.
Really illustrates how lossy the open baffle dipoles can be. On the other hand, the Manzanita is the only speaker I have heard that can make a piano sound like a live piano so the trade-off is worth it.
Many thanks