A Test. How much Voltage (power) do your speakers need? - Page 61 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
View Poll Results: I measured the test tone at:
2 volts or less 150 37.50%
Between 2-5 volts 137 34.25%
Between 5-10 volts 51 12.75%
Between 10-20 volts 24 6.00%
Over 20 volts. 38 9.50%
Voters: 400. You may not vote on this poll

Reply
 
Thread Tools Search this Thread
Old 8th March 2012, 11:36 PM   #601
diyAudio Member
 
ArtsyAllen's Avatar
 
Join Date: Mar 2011
Location: Ironwood, Upper MI
Smile This was very helpful, Thanks

It took me awhile to find the right recording to get a truthful answer. I ended up using the VU meter in foobar to help me find a recording that would use the dynamic range available in my PC-based pre-amp.

My favorite recordings, although recorded relatively dynamic, peaked around -6dB, resulting in RMS readings of 18 volts, the full RMS voltage of my chip amps! DVD movies fall into this catagory also.

If I played compressed internet radio music, I got RMS readings at 6 volts.

Once I found a recording that used the full gain of the pre-amp without clipping, I got a reading of 9.66 volts. So I voted for the 5-10 group.

I am sharing the above information, to hopefully help others realize the importance of playing the right recording to get the most helpful answer out of this test. It would be a shame to build a 200 watt amp and not "need" it!

My system is as follows:

Alpair 12s in Avebury cabinet - Full-range 89 dB efficent, 8 ohm
PC based playback system - Realtek audio (not the best)
Peter Daniel's standard LM3875 chip amps (18 volt RMS)
My room is 10ft X 14ft with openings on the sides.

Conclusions:

I need a bigger amp, at least for Avebury. Based on the math given above, i need a 94.74 watt amp, lets say 100 watt amp to run this system in this room, with dynamic material, esp movies. The chip amps are my first amp build, so... But, at least I know why they were chipping and what to shoot for next, atleast in requards to Avebury.

The Chip amps would be suited for a more sensitive speaker system, say 94dB or above?!? The future build perhaps...

It is safe to admit at this point that I like it Loud, when it is clear and fatigue free.

Allen
  Reply With Quote
Old 9th March 2012, 01:38 AM   #602
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Kona, Hawaii
Blog Entries: 4
Allen. Thanks for your results.

Yes, if you got 9.66V from the test tones at your volume setting then I'd say you need at least an amp rated at 95 WPC 8 ohms to keep from clipping. Of course most of the musical signal is far below that, but you still need a 95 watt amp not to crush your >38V peaks.
  Reply With Quote
Old 25th March 2012, 06:37 PM   #603
palmito is offline palmito  United States
diyAudio Member
 
palmito's Avatar
 
Join Date: Dec 2010
Location: Florida,US
Thanks for doing this pano.

My system is:

Acoustat 2+2 speakers
Revel B12a subwoofer
dcB1/ldr as a preamp
Modified Behringer DEQ2496 as a dac
mpd on ubuntu on spdif output
everything but your test files are flacs
gmpc client

I used folk/rock cuts to get to the "max" level. Since the Acoustats are full range I measured both frequencies, with the sub in and out:

120Hz (sub turned off) - 11.34v
220Hz (sub on) - 11.5v
  Reply With Quote
Old 25th March 2012, 09:01 PM   #604
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Kona, Hawaii
Blog Entries: 4
Thanks for testing!

At first that seemed like a lot of voltage, until I realized that the Acoustat is an electrostatic panel and 4 ohm. That makes sense. You'll need a big amp to stay out of clipping.
Maybe 250W @ 4ohms, or better to hit your peaks of 46 volts.
  Reply With Quote
Old 25th March 2012, 10:47 PM   #605
palmito is offline palmito  United States
diyAudio Member
 
palmito's Avatar
 
Join Date: Dec 2010
Location: Florida,US
Quote:
Originally Posted by Pano View Post
You'll need a big amp to stay out of clipping.
Maybe 250W @ 4ohms, or better to hit your peaks of 46 volts.
Yes, the PS Audio is rated at 400W @4 ohms... Not the best sounding, but it doesn't complain when driving the Acoustats to loud levels. I also have them in a large room and sit about 13' from them.
  Reply With Quote
Old 1st April 2012, 11:56 PM   #606
diyAudio Member
 
Join Date: Feb 2010
Location: Powell River, BC Canada
Pano - I just found this fascinating thread as a result of reading one of your posts in the Class D thread and seeing the footnote about it.

I did the test yesterday. Our system (the part used for the test) is a pair of upgraded 1958 Klipschorns driven by an old Harman Kardon 430 SS amp. (For some reason the Khorns love that amp!) All of our sources are on our HTPC that contains an Asus Essence ST soundcard that feeds the power amps directly. We use JRiver MC17 as a player and use its internal 64 bit volume control.

I used Steely Dan Two Against Nature for the reference music. I downloaded your test tones and used the 220 HZ tone.

Played the Steeley Dan about as loud as we would care to listen to it in our 1755 cubic foot room, which BTW is quite small for KHorns. Got 2.51 volts on a DMM.

The Khorn is rated as an 8 ohm speaker. Based on that our amp was putting out 3/4 watt and x 4 = 3 watt peaks. I believe the Khorn bass bin is closer to 6 ohms at that frequency so that would be 1 watt from the amp and 4 watt peaks. No wonder Paul Klipsch liked to say "It's the first watt that counts!" The Khorns are 104 DB sensitive speakers.

I also used a Radio Shack analog Sound Level Meter at the LP which is 10 feet from the Khorns. Got 94 DB on the reference music and 90 DB on the Sine Wave.

In reviewing the test I did as I write this I think I made some mistakes. I had both stereo speakers going and our Danley DTS-10 sub on. Don't think the sub was doing anything @220, but it seems a proper test to know how much power (voltage, SPL whatever you want to call it) would be to only have the one channel driven that is being used for the test. I could certainly have played it at a higher voltage if only the one speaker was on.

So my figures may be (probably are) flawed. I haven't heard this issue discussed, but it may be that I'm the only one here that ran both speakers when only testing one! I'll run the test again with only the one side on, but it may be awhile.

Also I have in storage a very old Tektronix 453 scope. If it still works, and is still in any kind of calibration, it will be very interesting to see at what point clipping occurs on the old HK amp that is rated for 30 WPC. It is though a very honestly rated amp and has dual power supplies. Of course with the Khorns in our small room I might need ear protection when I run enough power to drive it to clipping.

Pano I want to thank you very much for devising this thoroughly ingenious test. I think it makes a lot of sense and is certainly something that most anyone can do without any fancy test equipment.

Rod
  Reply With Quote
Old 14th April 2012, 08:43 PM   #607
Siberia is offline Siberia  Lithuania
diyAudio Member
 
Siberia's Avatar
 
Join Date: Feb 2011
Location: Vilnius
Hello,

My results:

Room L7.2mxW5.7mxH4.50m
Speakers 89.5dB/W/m

Measuring 3.205V
  Reply With Quote
Old 14th April 2012, 09:01 PM   #608
Siberia is offline Siberia  Lithuania
diyAudio Member
 
Siberia's Avatar
 
Join Date: Feb 2011
Location: Vilnius
Nominal impedance of speakers: 8 ohms (minimum 5.7 ohms) and that gives me around 15W, correct? Can't believe this.
  Reply With Quote
Old 14th April 2012, 11:56 PM   #609
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Kona, Hawaii
Blog Entries: 4
Hi NW boater. Sorry I missed your reply back on the 1st.

You should be running both speakers to set your loud listening level, unless you are in the habit of listening to only one at a time. The test tells you how much voltage you need per channel. It would not be right to set your loudest level using only one speaker if you normally listen to two. The voltage on the other channel should be the same, but of course power will be doubled because you are running twice the number of channels.
  Reply With Quote
Old 15th April 2012, 12:02 AM   #610
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Kona, Hawaii
Blog Entries: 4
Siberia - your numbers look about right. If you got 3.2V on the test tone, then you should be hitting just over 20W peak into a nominal 8 ohm load. An amp that is honestly rated at about 10WPC into 8 ohms should just be clipping. My guess is you'd want an amp of about 20W RMS to keep well clear of clipping.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
LM3875 power up test.. and it crackles w/o speakers attached? Keyoke Chip Amps 9 2nd March 2012 02:39 AM
how to test chokes for current and voltage speakerfritz Tubes / Valves 10 20th October 2010 12:32 PM
Aleph 30 problem - half of power supply voltage on speakers output yoke Pass Labs 18 15th March 2009 06:18 PM
How to test speakers? zaydenam Multi-Way 2 27th August 2008 02:02 PM
Test speakers? Ryssen Multi-Way 3 2nd March 2004 11:54 PM


New To Site? Need Help?

All times are GMT. The time now is 08:04 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2