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type: channel
description: Audio advice and discussions with audiophiles and professionals. Free discussion forums, open to all and frequented by industry experts. Ask questions and get advice on stereos, speakers, hi-end amplifiers, pre-amps, home theater, tube hi-fi, turntables, vinyl, tweaks, music, films, video, DVDs and more.
items: How do I measure the Le of a speaker?
items: Re: How do I measure the Le of a speaker?
items: LCR meter

How do I measure the Le of a speaker?
type: item
description: "Le This is the voice coil inductance measured in millihenries (mH). The industry standard is to measure inductance at 1,000 Hz. As frequencies get higher there will be a rise in impedance above Re. This is because the voice coil is acting as an inductor. Consequently, the impedance of a speaker is not a fixed resistance, but can be represented as a curve that changes as the input frequency changes. Maximum impedance (Zmax) occurs at Fs." I'm trying to implement a Zobel on a Trusonic FR80. I would like to find the TS's for this speaker. Thanks...Tre'
creator: Tre'
date: 2006-04-05T14:06:09-00:00

Re: How do I measure the Le of a speaker?
type: item
description: Measure the impedance of the speaker to find Le. It will be a complex impedance, having both reactance and resistance. You can use a Wheatstone bridge (inside a dedicated tester) or one of the measurement systems like Speaker Workshop to find impedance of your speaker.
creator: Wayne Parham
date: 2006-04-05T15:28:21-00:00

LCR meter
type: item
description: Like from Parts Express. I use mine often for testing tolerence of caps and coils! Ron
creator: spkrman57
date: 2006-04-05T23:35:09-00:00

Re: How do I measure the Le of a speaker?
type: item
description: Unfortunately, the effective Le and Re of the speaker's voice coil are going to change with increasing frequency. Fortunately, the Zobel circuits are not that sensitive so getting a Le and Re result at 1 kHz is good enough for sizing the Zobel. This is why there is typically a 25% factor in the rule of thumb equations for calculating the Zobel's capacitance and resistance. Martin
creator: Martin
date: 2006-04-06T22:02:08-00:00

Re: How do I measure the Le of a speaker?
type: item
description: Thanks, but how do I measure inductance at 1K hz? Can I make a inductance bridge like a impedance bridge? I have an inductance meter but I don't know what freq. it uses. Tre'
creator: Tre'
date: 2006-04-07T03:44:11-00:00

Re: How do I measure the Le of a speaker?
type: item
description: I found it. Le=(sqrt(3)*Re)/(2*pi*fx) I have to find Re and fx first, but the article shows how to do that. Thanks...Tre' Speaker how to
creator: Tre'
date: 2006-04-07T04:07:19-00:00