question of theory
 User Name Stay logged in? Password
 Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read Search

 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
 6th May 2004, 12:41 AM #1 cominup   diyAudio Member   Join Date: Apr 2004 Location: hanoi question of theory Dear all, Please, could you explain something below: First: - I know that impedance of loudspeaker is not constant while they are being used. It rates to audio frequency. But I dont know it rates directly or inversely. - Otherwise, power (Watt) inversely rates to impedance (ex: 8 Ohm ~ 100W; 4 Ohm ~ 200W). => So, I am asking the relationship between audio frequency and power. Second: - Wide audio frequency bandwidth causes wide loudspeaker impedance bandwidth. But speaker manufactors just tell us only one power (ex: 100W @ 8 Ohm). So, how to know the loudspeaker impedance bandwidth. What is the marked power on the loudspeaker? Third: - The relationship of amplifier power (Watt), loudspeaker sensity (dB) and loudspeaker power (Watt). Are there some equation and/or formula of them? Or it is just only human feeling? Thanks for your looking. Regards, Cominup __________________ Ill do it by myself
 6th May 2004, 06:37 AM #2 sreten   R.I.P.   Join Date: Nov 2003 Location: Brighton UK Speakers sensitivity is rated at dB/2.83V. For an 8 ohm nominal driver / loudspeaker dB/2.83V = dB/W For an 6 ohm nominal driver / loudspeaker dB/2.83V = dB/1.3W For an 4 ohm nominal driver / loudspeaker dB/2.83V = dB/2W For an 2 ohm nominal driver / loudspeaker dB/2.83V = dB/4W The above are just approximations as real efficiency at each point of the impedance curve is hardly ever considered. sreten.
 6th May 2004, 09:59 PM #3 Ron E   diyAudio Member     Join Date: Jun 2002 Location: USA, MN Re: question of theory 1. Ohms Law: Volts = Current * Impedance Power = Current^2*Impedance Power = Volts^2/Impedance Power doubles into a halved impedance only if voltage is constant and source impedance = 0. 2. Impedance bandwidth (whatever you mean by that) is unimportant. Impedance only matters in most cases if it is too low or too reactive. The marked power on a speaker is rated by IEC or DIN specifications. THese are a band-limited noise signal that is used to find the thermal (not mechanical) limits of the speaker. Search for "IEC power" or DIN power" in your browser. 3. efficiency = 9.6e-10*Fs^3*Vas/Qes [Vas in liters] sensitivity = 112+10*log10(efficiency) SPL in dB = 10*log10(power) +Sensitivity __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. —Aldous Huxley
 7th May 2004, 04:28 AM #4 cominup   diyAudio Member   Join Date: Apr 2004 Location: hanoi Hi Ron E, Many thanks for yr help, Cominup __________________ Ill do it by myself

 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 Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Site     Site Announcements     Forum Problems Amplifiers     Solid State     Pass Labs     Tubes / Valves     Chip Amps     Class D     Power Supplies     Headphone Systems Source & Line     Analogue Source     Analog Line Level     Digital Source     Digital Line Level     PC Based Loudspeakers     Multi-Way     Full Range     Subwoofers     Planars & Exotics Live Sound     PA Systems     Instruments and Amps Design & Build     Parts     Equipment & Tools     Construction Tips     Software Tools General Interest     Car Audio     diyAudio.com Articles     Music     Everything Else Member Areas     Introductions     The Lounge     Clubs & Events     In Memoriam The Moving Image Commercial Sector     Swap Meet     Group Buys     The diyAudio Store     Vendor Forums         Vendor's Bazaar         Sonic Craft         Apex Jr         Audio Sector         Acoustic Fun         Chipamp         DIY HiFi Supply         Elekit         Elektor         Mains Cables R Us         Parts Connexion         Planet 10 hifi         Quanghao Audio Design         Siliconray Online Electronics Store         Tubelab     Manufacturers         AKSA         Audio Poutine         Musicaltech         Holton Precision Audio         CSS         Dx Classic Amplifiers         exaDevices         Feastrex         GedLee         Head 'n' HiFi - Walter         Heatsink USA         miniDSP         SITO Audio         Twin Audio         Twisted Pear         Wild Burro Audio

 Similar Threads Thread Thread Starter Forum Replies Last Post stereo.pete Everything Else 5 15th April 2009 02:03 PM DougL Multi-Way 13 18th March 2005 01:57 AM leadbelly Multi-Way 8 19th January 2004 05:39 PM Petter Parts 12 17th January 2003 01:46 PM Andrej Multi-Way 6 28th April 2002 06:53 AM

 New To Site? Need Help?

All times are GMT. The time now is 12:30 PM.

 Home - Contact Us - Advertise - Rules - diyAudio Store - Sponsors - Privacy Statement - Terms of Service - Top - Opt-out policy

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.