A Test. How much Voltage (power) do your speakers need?
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 Multi-Way Conventional loudspeakers with crossovers

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 View Poll Results: I measured the test tone at: 2 volts or less 244 38.73% Between 2-5 volts 202 32.06% Between 5-10 volts 85 13.49% Between 10-20 volts 42 6.67% Over 20 volts. 57 9.05% Voters: 630. You may not vote on this poll

Pano
diyAudio Moderator

Join Date: Oct 2004
Location: SW Florida
Sorry Jerome, I don't understand what you mean.
Quote:
 Originally Posted by jerome69 No problem for my amp, 500W of power behind them, 50W/8ohms --> 100W/4ohms
To me, an amp that is rated 50WPC @8 ohms means that it can deliver 20V RMS on a sine wave before clipping. That would be 28.3V peak. It won't deliver more voltage into a 4 ohm load, it will be the same, or maybe a little less.

Your measurement of 12.6V RMS on the -12dB tone means that you need 4X 12.6V for the peaks. Or just over 50 volts. It seems to me that you would need to bring your average level down by 6dB to avoid clipping. No?

 22nd January 2012, 07:14 PM #62 jerome69   diyAudio Member     Join Date: Feb 2008 Location: Lyon Yes you are right. It is my own amp, +-35V voltage. The voltage doesn't change but the power yes, and my amp can supply this power : 100W/4ohms. My music is not at 0dB level ! I put my favorite music at maximum level i can listen to it and after i measured the test tone. I think it is the explanation of this difference, unless i didn't understand the procedure . Ok i reach the limit of my amp, the result should be 7V (6db less) ? BTW the OB could provide (80 + 20) 100dB SPL
 22nd January 2012, 07:31 PM #63 jtalden   diyAudio Member   Join Date: May 2009 Location: Michigan I voted as 5-10 V I normally listen to contemporary music at about 4.5 V but sometimes go 2 or 3 dB louder. I listen to Classical at higher settings, with the highest setting corresponding to 13 V. This is at my limit and rarely done. DIY Speakers - SEAS ER18RNX (6.5”) 8 Ohm Mid-Woofer [Characteristic Sensitivity 88.5 dB (2.83V, 1m)] 240 Hz test signal was used as the XO to SWs is at 100 Hz and there is EQ boost impacting 120 Hz range. 210 m^3 (7400 ft^3) room with LP at 4 m.
Pano
diyAudio Moderator

Join Date: Oct 2004
Location: SW Florida
Thanks JT. That's a nice big room with average sensitivity speakers, very nice to know. Your contemporary vs classical also seems right in line. Classical recording can be very dynamic. In your case about 9dB more dynamic.

Quote:
 Originally Posted by jerome69 I think it is the explanation of this difference, unless i didn't understand the procedure
Maybe. Let me see if I can explain again.

When you measure the -12dB test tone, music peaks will be 12dB (4X) higher when playing at that same volume setting. That's how digital recordings work. -12dB will always be 1/4 the voltage of 0dB. 0dB is is the highest possible level.

Now; you could set your volume to its "normal" setting and measure there, but that would not tell you how much voltage you need to play it loud. As loud as you ever do. We are looking for the most you ever use.

I choose -12dB for several reasons, one being that it isn't likely to blast out your ears or speakers, and not make the neighbors call the cops.
Another reason is because it's easy to do the 4X multiplication in your head to know the absolute peak voltage.

 22nd January 2012, 07:59 PM #65 KSTR   diyAudio Member     Join Date: Jul 2007 Location: Central Berlin, Germany I measured 1.9Vrms with the 220Hz test tone, after listening to some songs with my typical levels which I consider moderate, at 80...90dB averages on a C-weighted meter, slow setting. The test tone read 92dBC at the listening position.
 22nd January 2012, 08:03 PM #66 Pano   diyAudio Moderator     Join Date: Oct 2004 Location: SW Florida Thanks! So at your normal levels you might be hitting 104dB peaks?
 22nd January 2012, 08:08 PM #67 jerome69   diyAudio Member     Join Date: Feb 2008 Location: Lyon The most level i ever use, (knob 8h45) is easy to measure : 1.5V RMS 9W 89.5dBSPL. But sometimes I play loud (1h10) seems to be the overall power of the amp.
 22nd January 2012, 08:20 PM #68 auplater   diyAudio Member     Join Date: Apr 2005 Location: KyOhWVa tristate I measured ~3.05 volts with receiver @0dB (movie reference setup by Audigy on Denon 3808) Home built RD75 open baffle w/woofers, no subs @120 Hz This in a 25' x 40' x 2 story room with lots of furniture. At 15', the spl measures ~ 82 - 85 dB, depending on room modes. They'll go alot louder, but wife is home... __________________ "I've forgotten more than I care to remember" The Last Conspirators Last edited by auplater; 22nd January 2012 at 08:24 PM.
 22nd January 2012, 08:27 PM #69 Pano   diyAudio Moderator     Join Date: Oct 2004 Location: SW Florida Thanks. You've posted photos of your speaker on the forum, right?
 22nd January 2012, 08:41 PM #70 MethMan diyAudio Member   Join Date: Jun 2004 Location: Praha 120Hz 3.76V 220Hz 3.53V Loud enough and comfortable with well recorded material. 12.15V, 11.6V at the end of the party around 5am (death metal records) My weak NAD amp is capable of 40V or so. Speakers: Gedlee Nathans __________________ Tomas Last edited by MethMan; 22nd January 2012 at 08:44 PM. Reason: speakers added

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