Thanks for your results. Yes, open baffle is lossy and needs power, the smaller the baffle the higher the losses. I'd call the Manzanita a small(ish) open baffle. A big room will also soak up the sound.
When I had the Manzanitas in the lava cave, I could have used every bit of my Crest 700 WPC amp for headroom (75 volts RMS maximum.) But I kept the amp turned down to 28 volts RMS max to be kind to the tweeters. Had to sneak it up to 35 volts RMS max to get near the dynamics needed. Those would measure approximately 19V, 7V and 8V on the test signals.
Your 15.5V just goes to show how much headroom you need on a dynamic piece of music!
Good to get a report on the Manzie.
When I had the Manzanitas in the lava cave, I could have used every bit of my Crest 700 WPC amp for headroom (75 volts RMS maximum.) But I kept the amp turned down to 28 volts RMS max to be kind to the tweeters. Had to sneak it up to 35 volts RMS max to get near the dynamics needed. Those would measure approximately 19V, 7V and 8V on the test signals.
Your 15.5V just goes to show how much headroom you need on a dynamic piece of music!
Good to get a report on the Manzie.
As a newbie to audio, I really like this test for helping me understand power and loudness. I've built one pair of loudspeakers (MarkAudio Pluvia 7 in a ~13L vented cabinet) and I drive them with a 1970s Nikko 20W receiver. Currently they are on my workbench about 1 meter away from my head.
Playing the test tone, my voltmeter measured around 0.5V at the loudest volume setting that is comfortable for music listening. That was a surprise to me that I would only need a 1/4W RMS power amplifier in this location with these speakers. I knew that desktop use didn't require much power, but I didn't think it would be that small!
I'll repeat the measurement once the system moves out to its final destination in my living room. Thanks again for this simple approach to understanding how loud is loud enough. Anyone have plans for a DIY 1W power amplifier?
-Neil N0FN
Playing the test tone, my voltmeter measured around 0.5V at the loudest volume setting that is comfortable for music listening. That was a surprise to me that I would only need a 1/4W RMS power amplifier in this location with these speakers. I knew that desktop use didn't require much power, but I didn't think it would be that small!
I'll repeat the measurement once the system moves out to its final destination in my living room. Thanks again for this simple approach to understanding how loud is loud enough. Anyone have plans for a DIY 1W power amplifier?
-Neil N0FN
Well, actually, Nelson Pass - none other - has plans for a 1W AMP:...Anyone have plans for a DIY 1W power amplifier?
FAOW
He calls it the First And Only Watt (FAOW) Amp.
So, have fun!!!, you can certainly trust the source!!!
Rafa.
OK, a bit of a voltage test goof I hope folks find amusing/interesting.....
I needed to do a little glue repair, spider-to-cone, on an 18" driver from a double 18 sub.
Pulled the driver, glued it, and set it on top the sub, which is physically located about 10ft away from the other double 18" in the room.
Started cranking some tunes using just the one good sub, but began wondering if passive resonance would move the driver under repair any, to the detriment of the glue setting up.
So I put my finder on the cone, and felt next to no movement. But I noticed the other driver in the sub cabinet was resonating quite a bit. Cabinet works I thought happily!
In fact, the in-box driver had so much passive resonance, I decided to measure the voltage it was putting out while cranking Red, Red, Wine
Over 3v rms peaks at least 50ms long...along with an average rms right around 1v.
Coming out of the driver, not going in LoL
I needed to do a little glue repair, spider-to-cone, on an 18" driver from a double 18 sub.
Pulled the driver, glued it, and set it on top the sub, which is physically located about 10ft away from the other double 18" in the room.
Started cranking some tunes using just the one good sub, but began wondering if passive resonance would move the driver under repair any, to the detriment of the glue setting up.
So I put my finder on the cone, and felt next to no movement. But I noticed the other driver in the sub cabinet was resonating quite a bit. Cabinet works I thought happily!
In fact, the in-box driver had so much passive resonance, I decided to measure the voltage it was putting out while cranking Red, Red, Wine
Over 3v rms peaks at least 50ms long...along with an average rms right around 1v.
Coming out of the driver, not going in LoL
Pano,
This is exactly what I was looking for! Thanks for the test tones and description of how to use them... very clever. Short version: The highest volume level I've ever used resulted in 8.65V using the 120Hz tone on an 8 ohm mid woofer with sensitivity of 86 dB. I was hoping for <5V, but am happy I know what I need now.
Long version: I have a tri-amped active system that I've been listening to for a few years now with some DIY speakers I've made. Recently I've wanted to try some new amplifiers and needed a way to determine the voltage required to power my mid woofers. I've been happy with my relatively low powered amps, but have always wondered if they were enough.
Currently, I use a 2 channel amp to power the left tweeter/woofer and a 2 channel amp for right tweeter/woofer. I have a separate amp for sub. The t/w amps produce 25 watts rms of clean power per channel. That suggests that I am most likely experiencing some clipping on the woofer channels when listening at party levels. It's funny because they really sound clean.
Thankfully my normal "very loud" listening level resulted in almost exactly 5V. Your test tone was very useful in my case because 120Hz is just about right where the woofer requires the most voltage (above my high pass filter and below BSC).
I was hoping to build some 25 watt chip amps to power the speakers. I looks like 75 watts for the woofers would be more appropriate if I want to prevent the signal from hitting the rails. Of course, 25 watts is more than enough for the tweeters.
Anyone else measure a higher voltage than expected?
This is exactly what I was looking for! Thanks for the test tones and description of how to use them... very clever. Short version: The highest volume level I've ever used resulted in 8.65V using the 120Hz tone on an 8 ohm mid woofer with sensitivity of 86 dB. I was hoping for <5V, but am happy I know what I need now.
Long version: I have a tri-amped active system that I've been listening to for a few years now with some DIY speakers I've made. Recently I've wanted to try some new amplifiers and needed a way to determine the voltage required to power my mid woofers. I've been happy with my relatively low powered amps, but have always wondered if they were enough.
Currently, I use a 2 channel amp to power the left tweeter/woofer and a 2 channel amp for right tweeter/woofer. I have a separate amp for sub. The t/w amps produce 25 watts rms of clean power per channel. That suggests that I am most likely experiencing some clipping on the woofer channels when listening at party levels. It's funny because they really sound clean.
Thankfully my normal "very loud" listening level resulted in almost exactly 5V. Your test tone was very useful in my case because 120Hz is just about right where the woofer requires the most voltage (above my high pass filter and below BSC).
I was hoping to build some 25 watt chip amps to power the speakers. I looks like 75 watts for the woofers would be more appropriate if I want to prevent the signal from hitting the rails. Of course, 25 watts is more than enough for the tweeters.
Anyone else measure a higher voltage than expected?
I just did an arena, as it was very time limited my guys set the limiter for 18.89 volts RMS for all the loudspeakers. All the loudspeakers were full range and it was just fine. Next week they will go back and make the limiter frequency selective which they could quickly figure out how to do that with a rather quirky processor.
Wow, the driver was moving that much from just the airborne bass?You are welcome. It's good to understand where you are in terms of headroom and clipping. Usually we just don't know.
That's surprisingly low. Let us know what other limits you find. Thanks for the data.
snip
…Anyone have plans for a DIY 1W power amplifier?
-Neil N0FN
I am currently building a monster of an amp with a ground pounding 1.5w/ch output for my headphone system.
It currently has 15 xfmrs with 2 (or possibly more) to be added up the road.
It is 24" long and 12" wide and needs at least 4" of depth.
It has 2) 45 output tubes and 2) 6J5 line drivers which means it uses 2, single triodes/ch.
A really simple analog section.
The power supply is simple too but is a massive LCLCL overkill design using parafeed output xfmrs, all for that earthquake triggering 1.5w/ch.
I'm aiming to be wonderfully surprised and gratified by all that lovely Tube Magic in the Mids.
JJ
Yes, a full volt output !!! Crazy huh? I only measured it because the resonant vibration felt so strong to the touch.
I even took a transfer function Lol....
this is the electrical output of the driver, vs the reference signal going to the sub that was playing across the room (loudly
)Obviously ignore the relative levels. But one interesting thing was the transfer function was stable...note the coherence in sub range LPF @100
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I measured with a rock vinyl (lol) with volume to almost maximum on a 6 ohm test resistor and the highest peak to peak was 6 Volts.
This is 6Vx.35=2.1Vrms. Max power peak 2.1*2.1/6 =0.75 watts and this blasts with typical speakers to uncomfortable levels in the whole house.
I then placed this resistor with same record playing in an insulated water bucket and see after 4 minutes temperature rise. The resistor was warm if I touched it but never like if I test with test tones, music doesn't have this continuous power draw.
The total sum of all music harmonics at max power was probably in the order of 2 watts but not enough to change water temperature for 4 minutes.
This was done with an oscilloscope. With actual Output transformer losses we can say the maximum peak measurable power needed was around 0.9 watts!
This is 6Vx.35=2.1Vrms. Max power peak 2.1*2.1/6 =0.75 watts and this blasts with typical speakers to uncomfortable levels in the whole house.
I then placed this resistor with same record playing in an insulated water bucket and see after 4 minutes temperature rise. The resistor was warm if I touched it but never like if I test with test tones, music doesn't have this continuous power draw.
The total sum of all music harmonics at max power was probably in the order of 2 watts but not enough to change water temperature for 4 minutes.
This was done with an oscilloscope. With actual Output transformer losses we can say the maximum peak measurable power needed was around 0.9 watts!
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Thanks for the numbers! I'm surprised they aren't a little higher, as the M2 is rated at 92dB/watt and you like to rock out.
Also curious about the differences between 120Hz and 220Hz. I confirmed that the levels are the same in both files, so why are you getting different output levels on the CD? And is it BSS EQ that changes the level after, or impedance?
Also curious about the differences between 120Hz and 220Hz. I confirmed that the levels are the same in both files, so why are you getting different output levels on the CD? And is it BSS EQ that changes the level after, or impedance?
Thanks for the numbers! I'm surprised they aren't a little higher, as the M2 is rated at 92dB/watt and you like to rock out.
Also curious about the differences between 120Hz and 220Hz. I confirmed that the levels are the same in both files, so why are you getting different output levels on the CD? And is it BSS EQ that changes the level after, or impedance?
I really don't know!
Thanks for the numbers! I'm surprised they aren't a little higher, as the M2 is rated at 92dB/watt and you like to rock out.
"Rocking out" isn't a problem, most of the time.
That's because most POP & Rock music is heavily compressed, and it sounds LOUD at modest peak power levels because the average level is only a few dB below that.
OTOH, some audiophile Classical and Jazz recordings can have a peak-to-rms ratio in excess of 20, even 23 dB. If you listen to these and want to achieve realistic average levels, you need to turn up the volume knob considerably, and that's when you need amplifier headroom (read: MUCH more power on tap).
Marco
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Yes indeed. That has been discussed a few times in this thread, but always bears repeating. Peaks on a lot of recent recordings aren't much higher than the average levels.
That's the problem with a test like this; getting people to choose the right tracks for level setting. Many people will choose a track they perceive as loud to set top levels, when in fact that loudness comes mostly from limited dynamic range. Yes it's loud, but needs very little headroom.
Having listened to jtwrace's former system, I know that he listens to music with pretty good dynamics and the peaks can get way up there.
That has been discussed a few times in this thread, but always bears repeating. Peaks on a lot of recent recordings aren't much higher than the average levels.That's the problem with a test like this; getting people to choose the right tracks for level setting. Many people will choose a track they perceive as loud to set top levels, when in fact that loudness comes mostly from limited dynamic range. Yes it's loud, but needs very little headroom.
Having listened to jtwrace's former system, I know that he listens to music with pretty good dynamics and the peaks can get way up there.
