XPA-2 LED display - wattage question

[johto]

Hi guys!

I've had the XPA-2 now for couple months and its fabulous!
See ( emotivalounge.proboards.com/index.cgi?board=xpa2&action=display&thread=28409 )

One quick question if somebody knows the answer:
I have 91dB/1w sensitive speakers (KEF Q900) and very rarely even see the power LED's moving even single step with my casual music listening (two lights per channel). ;D That's a good thing! Good to know i have reserves, if i happened to need more

What is the wattage usage on XPA-2 with a certain LED blinking? Example the second LED per channel? Would be interesting to know.

Thanks!
(*opens cider and beer...Friday after all ...*hick up*)
Cheers from Finland !

[geebo]

Apr 5, 2013 10:05:22 GMT -5 johto said:

Hi guys!

I've had the XPA-2 now for couple months and its fabulous!
See ( emotivalounge.proboards.com/index.cgi?board=xpa2&action=display&thread=28409 )

One quick question if somebody knows the answer:
I have 91dB/1w sensitive speakers (KEF Q900) and very rarely even see the power LED's moving even single step with my casual music listening (two lights per channel). ;D That's a good thing! Good to know i have reserves, if i happened to need more

What is the wattage usage on XPA-2 with a certain LED blinking? Example the second LED per channel? Would be interesting to know.

Thanks!
(*opens cider and beer...Friday after all ...*hick up*)
Cheers from Finland !

I'd be curious to know that as well. It seems that another member raised that question a short time ago was going to run some tests to find the answer. Perhaps he'll chime in...

[The Mad Norseman]

I'd also like to know, but for the XPR-5's LED read outs.

My floor-standing front speakers are also 91db sensitivity @ 1 watt input at 1 meter, and are 8 Ohms (nominal).
But when the XPR-5's LEDs go up, what exactly (or even 'generally') am I looking at?
The XPR-5 has 12 LEDs per channel, the bottom one is always lit, the top one is red (I think), but have never seen that one lit except momentarily upon turn on - with all the others...

I think the XPA-2's LEDs are calibrated differently than the XPR-5's are because I can sure make mine "dance" (but not ALL the way up!).

[Deleted]

With my XPA-1's and my Tyler's, i could get it to hit the red LEDs. They have a sensitivity rating of 101db.

I'm pretty sure these meters are not constant or exact. While using my XDA-1, i get the lights dancing. With the volume with in a few db using my turntable, i get no lights dancing, not even turning the volume up with get them to move.

So they are not very accurate......

[AudioHTIT]

Apr 5, 2013 13:40:25 GMT -5 @kraemerkid2119 said:

With my XPA-1's and my Tyler's, i could get it to hit the red LEDs. They have a sensitivity rating of 101db.

I'm pretty sure these meters are not constant or exact. While using my XDA-1, i get the lights dancing. With the volume with in a few db using my turntable, i get no lights dancing, not even turning the volume up with get them to move.

So they are not very accurate......

Don't they kind of have to be constant and exact? I mean they are being driven by some part of the signal path and a given voltage at that point will turn on a specific number of lights. This could be correlated to a specific wattage with a known load. Problem is, Emo has never specified what the output voltage is for each LED. Someone will need to (carefully) measure this someday.

[geebo]

Apr 5, 2013 15:24:56 GMT -5 AudioHTIT said:

Apr 5, 2013 13:40:25 GMT -5 @kraemerkid2119 said:

With my XPA-1's and my Tyler's, i could get it to hit the red LEDs. They have a sensitivity rating of 101db.

I'm pretty sure these meters are not constant or exact. While using my XDA-1, i get the lights dancing. With the volume with in a few db using my turntable, i get no lights dancing, not even turning the volume up with get them to move.

So they are not very accurate......

Don't they kind of have to be constant and exact? I mean they are being driven by some part of the signal path and a given voltage at that point will turn on a specific number of lights. This could be correlated to a specific wattage with a known load. Problem is, Emo has never specified what the output voltage is for each LED. Someone will need to (carefully) measure this someday.

I would think that they would have to be consistent in that a specific voltage of a specific frequency would always light a specific light.

[Deleted]

I just don't know why when i use my TT~2, i get no lights at all. Like at 100+db lol

Using the phono in the XSP-1 too!

[ocezam]

Apr 5, 2013 15:45:38 GMT -5 @kraemerkid2119 said:

I just don't know why when i use my TT~2, i get no lights at all. Like at 100+db lol

Using the phono in the XSP-1 too!

That's a bit wierd
.


..

[Deleted]

Apr 7, 2013 13:44:12 GMT -5 ocezam said:

Apr 5, 2013 15:45:38 GMT -5 @kraemerkid2119 said:

I just don't know why when i use my TT~2, i get no lights at all. Like at 100+db lol

Using the phono in the XSP-1 too!

That's a bit wierd
.


..

Sure is, i have no idea why....

[guitarforlife]

Matt, That is indeed strange.
Back in the day I had a realistic watt meter.

You hooked them up between you speakers and amp.
All I had back then was Tape decks and TT.
Now I don't know accurate these things were/are.

But they always moved no matter what source was being played.
So I would think the ones you have would/should as well. MMMM odd.

If you hooked a tape deck up and were to record from your TT to tape. The meters on the tape deck would move.
So it should have nothing to do with the source.

[stiehl11]

Apr 7, 2013 13:54:47 GMT -5 @kraemerkid2119 said:

Apr 7, 2013 13:44:12 GMT -5 ocezam said:

That's a bit wierd
.


..

Sure is, i have no idea why....

It's because you're not sending the same signal through the amp. As you know, it takes more power to generate lower frequencies than high and, depending on your speakers, you may have a lower resistance (Ohm) on the lower stages of your speaker crossover network than your high. For example on my speakers I dip to a apx. 2 Ohm resistance for any signals under 160 Hz. If it never sees under 160 Hz it never dips the resistance that low. The more signal it sees under 160 Hz, such as 20 Hz (along with duration), the more current the speaker draws from the amp.

So, using my speakers as an example because I'm unsure about Tyler speakers, if you were sending the same frequencies to your amp then the speakers would draw the same current from the amp regardless of source and everything would be equal as you expect it to be. But, if you were sending less full (or less low end) frequencies to the amp, not only would the amp not use as much current to reproduce non-existent frequencies but the speakers would not pull more current from the amp during reproduction of the non-existent frequencies as well. Despite what you think you're hearing you system is likely not reproducing as low or as full of a signal when you're not drawing as much current as compared to when you're playing from other sources. This could be from the media being used to the source player and pre-amp equipment being used. The amp and speakers are pretty much blunt instruments and will only work with the signal they're given. An example would be if I have a CD and an album and the album is only recorded down to 80 Hz and the CD down to 20 Hz. All things being equal; in my system my amp would draw more current reproducing the CD versus the album. This does not mean that I would be able to hear a difference between the two medias.

[guitarforlife]

Apr 7, 2013 15:33:35 GMT -5 stiehl11 said:

Apr 7, 2013 13:54:47 GMT -5 @kraemerkid2119 said:

Sure is, i have no idea why....

It's because you're not sending the same signal through the amp. As you know, it takes more power to generate lower frequencies than high and, depending on your speakers, you may have a lower resistance (Ohm) on the lower stages of your speaker crossover network than your high. For example on my speakers I dip to a apx. 2 Ohm resistance for any signals under 160 Hz. If it never sees under 160 Hz it never dips the resistance that low. The more signal it sees under 160 Hz, such as 20 Hz (along with duration), the more current the speaker draws from the amp.

So, using my speakers as an example because I'm unsure about Tyler speakers, if you were sending the same frequencies to your amp then the speakers would draw the same current from the amp regardless of source and everything would be equal as you expect it to be. But, if you were sending less full (or less low end) frequencies to the amp, not only would the amp not use as much current to reproduce non-existent frequencies but the speakers would not pull more current from the amp during reproduction of the non-existent frequencies as well. Despite what you think you're hearing you system is likely not reproducing as low or as full of a signal when you're not drawing as much current as compared to when you're playing from other sources. This could be from the media being used to the source player and pre-amp equipment being used. The amp and speakers are pretty much blunt instruments and will only work with the signal they're given. An example would be if I have a CD and an album and the album is only recorded down to 80 Hz and the CD down to 20 Hz. All things being equal; in my system my amp would draw more current reproducing the CD versus the album. This does not mean that I would be able to hear a difference between the two medias.

Ok, I'm a little slow. And would like to understand.

Are these not suppost to showing the db or watts or whatever.
Are you not sending a signal though no matter what?

I mean I can see a difference as far as not moving them up as high.
But I go back to my above post.
Why did those old analog VU meters move no matter what?

And If you hooked that TT up to a tape deck those meters would move as well. Now I know with the tape deck scenario you would adjust them up or down. But a signal would still be there.

And I have some Cd's that are recorded much quieter as well as some do not have the same range poor recordings like you say a LP would have.
Just wondering.

[geebo]

I think David may be saying that if you have two sources playing at, say, 95db and one has some heavy bass content and the other does not, the one with the heavier bass content will register higher on the meter even though both have the same SPL.

[guitarforlife]

Yes that makes sense.

But the way I understood it is that he has no"none" showing at all with the TT.

I have no idea how this amp is made. But would the LEDs be between the amp and speakers to get a reading of wattage?

And If not what are they for?
I love them and I think they look cool.
But if they don't read anything then what do they do?

I do not mean any of this in a bad way. Just do not understand.

[AudioHTIT]

Apr 7, 2013 18:47:07 GMT -5 guitarforlife said:

Ok, I'm a little slow. And would like to understand.

Are these not suppost to showing the db or watts or whatever.
Are you not sending a signal though no matter what?

I mean I can see a difference as far as not moving them up as high.
But I go back to my above post.
Why did those old analog VU meters move no matter what?

And If you hooked that TT up to a tape deck those meters would move as well. Now I know with the tape deck scenario you would adjust them up or down. But a signal would still be there.

And I have some Cd's that are recorded much quieter as well as some do not have the same range poor recordings like you say a LP would have.
Just wondering.

Actually the 'old' analog meters didn't ALWAYS move. Using Mac power amps for example (because they've used meters a long time) their original meters had a 23 dB range ( -20 to +3). Typically the meters were calibrated such that 0 dB represented rated power. On a 100 watt amp -20 dB would then represent 1 watt. If you had efficient speakers like any of the Klipsch horn models (popular with Mac back in the day), then you might do much of your listening below 1 watt and without much meter movement.

Starting with the MC2205 Mac changed to a switchable meter with over 40 dB of range (maybe even 60). Using the 100 watt example -40 would now give meter movement down at .01 watts, NOW you would likely see meter movement at most listening levels.

As for tape decks one reason you see movement there is that they measure line level signals which are independent of listening level, but even then the older tape decks (the original Nakamichi 1000 for instance), had a 23 dB meter and on soft passages you wouldn't get much movement. When they released the 1000 Mk II they added a 45 dB meter and again you got more movement at all levels.

So, to correlate this to LEDs what some vendors do is to have a specific LED (near the top) come on at rated power, then LEDs below that point come on at -3, -5, -10, whatever. We just don't know what Emo does.

(Note in the above these 'dB' are NOT SPL, and are just relative to a reference point - like rated power)

[tme110]

I've never even seen the lights move on my xpa-2 either. My Ascend towers are pretty efficient though.

[stiehl11]

Apr 7, 2013 19:10:18 GMT -5 geebo said:

I think David may be saying that if you have two sources playing at, say, 95db and one has some heavy bass content and the other does not, the one with the heavier bass content will register higher on the meter even though both have the same SPL.

Exactly, George...

The levels on your amp is the current or power that is being used; not the line level that is being brought to the amp such as what you would see on a tape deck. To borrow a bit from a post above using 100 watts: think how soft (i.e. negative db) you'd have to go when you're dealing with 500 watts for an XPA-2 or 1000 watts for a XPA-1!

I can get mine to dance (my speakers are 91 db). And, when I do, they dance a quite a bit (shows how much headroom you need for dynamic transients). But, to do so I'm at the high 80's at my listening position with peaks in the mid-high 90's, roughly 10 feet (3 meters) from my speakers. Even at that, I'm getting at most 3 dots lighting up per channel. I have never hit red on my XPA-2 (even playing the beginning of Dark Side of the Moon at 70 on my UMC-1; getting most but not all blue dots lighting up) and I'm likely to get the police called if I do.

[guitarforlife]

I guess the thing that still confuses me is this.

If these are showing a out put level.
Then any out put should have a reading.
I do understand that they may not be sensitive to read on lower passages but if I (or should I say kramer) turns his TT up as loud as his Cd's or music server.

then it should still read that level.
Unless these are not for reading the wattage or VU. that is being out putted?

I just thought that's what they are for.
So that is why I'm confused.

[stiehl11]

^Yes, they are for the wattage that is being used or out putted as you said.

Let's assume that the 10 LEDs are for 1, 2, 4, 8, 16, 32, 64, 128, 256, and 512 watts. In the example that I used above, with my speakers playing at the high 80's/low 90's with peaks as high as the high 90's giving me a second LED light on my XPA-2, kramer would be using about a tenth (1/10) of the power I would be with his speakers. For kramer to get his LEDs to move as much as I got mine to move, assuming that he was running the same media, media player, and pre-amp as me and his speakers drop to almost 2 ohm during the low frequencies, he would be well into the SPL as a blow dryer held up to your ear (pretty dang loud, especially compared to my relatively easy listening volume of about 90 dB). Now, if we change one of the assumptions; that his speakers stay at a constant 4 Ohm, then his speakers would now come close to or eclipse the loudest rock concert you've (arguably) been to or a screaming toddler or around 110 db! Now, lets change another assumption; along with his speakers staying no lower than 4 Ohm, the signal that goes to his XPA-2 stops at 80 Hz as opposed to earlier having a signal down to 20 Hz (may or may not be an audible difference, YMMV). Now his XPA-2 is out putting less wattage than it did when it was playing a signal down to 20 Hz, out putting less wattage than it did when it was playing 20 Hz at 4 Ohm, out putting less wattage than it did playing 20 Hz at 2 Ohm, and out putting less wattage than it did at 20 Hz at 2 Ohm into a 91 dB rated speaker. Therefore, with the same watt of power producing a full signal at approximately 90 dB with my speakers, kramer's Tyler's could potentially be producing close to 110 dB!!! To get to that second watt of power (or second LED using my assumption above) kramer could very well get peaks up to 120 dB and an average somewhere between 107 and 114 dB!!!