Impedance??

[Maui waui]

Hi there, I’m about to buy speakers for my turntable  wondering what’s impedance that’s shown on speakers label?

I imagine should be same value of the one shown on the receiver, what happen if you plug a speaker with different impedance value?

Cheers

[Steffen]

The impedance specified for the receiver is the minimum impedance the device can handle. You can connect speakers with an equal or higher impedance.

Edited September 12, 2019 by Steffen

[HypnoToad]

Speakers usually fall into two impedance categories, 4 or 8 ohms, their actual impedance varies with frequency and can drop below these levels, Magnepan planar speakers for example. But most cone driver speakers are designed not to fall too low and put a strain on your amp. The power output of a solid state amplifier increases the lower the impedance of the speakers, 4 ohm speakers are usually louder than 8 ohm speakers and most solid state amplifiers can handle them well.

 

So in effect it doesn't really matter if you buy 4 ohm or 8 ohm speakers if you are using a solid state amp, of course valve/tube amps have different taps on their output transformers for different impedance speakers so with them you need to match up the speakers with the correct outputs.

[Ittaku]

Not quite true. Some solid state amps only support 8 ohm, and many receivers only support 6 ohm.

[stereo coffee]

Noting that Impedance varies considerably with frequency, and what is quoted by speaker manufacturers is a nominal figure. 

 

An extreme example is the Quad ESL57 electrostatic - at 80 hz 33 ohms and at 18khz just 2 ohms. Moving Coil speakers 

in comparison whilst also varying do so with less variance - the Gale GS401a is an example of a difficult impedance load

dipping to 3.5 ohms and as high as 11 ohms at 400 hz . Each speaker are highly regarded.  Different again is the MBL101 

which embodies different technology being a moving magnet design, its impedance graph is  seen in the  last image 

 

Balanced against this is that conventional amplifiers are arranged as voltages sources, their limitations are in reality 

limited to ability to drive a loudspeaker cable.  Things will begin to get interesting when current drive instead accommodates

the ability to control a wildly varying impedance such as the Quad 57- in this regard amplifiers have a long way to

go to properly drive loudspeakers. 

[HypnoToad]

45 minutes ago, Ittaku said:

Not quite true. Some solid state amps only support 8 ohm, and many receivers only support 6 ohm.

 

Must be very few as I've never seen a solid state amp with a 6 or 8 ohm minimum.

 

 

Solid State (non-tube, and we're including those amps with tubes in the preamplifier stage) amplifiers will have a minimum impedance specification, for example "minimum 4 load. This value is usually printed or stamped next to the speaker output jack on the amp.

Here's why it's important: you'll find that the load (impedance) plugged into the unit affects the amount of power delivered to the speaker cabinet(s). For example, you may see a power rating of 350 watts into 8, 500 watts into 4 for a given amp. If you want and/or need the maximum available power the amp can potentially produce, you want to match the lowest impedance for which the amp is rated. But don't obsess about it, the difference in actual volume is typically not that great. Most solid-state amps will handle a 4 load, though those that will handle as low as a 2 load are becoming more common.

 

https://www.gollihurmusic.com/faq/31-OHMS_AND_IMPEDANCE_FROM_THE_OUTPUT_SPEAKER_PERSPECTIVE.html

[aussievintage]

6 minutes ago, HypnoToad said:

Must be very few as I've never seen a solid state amp with a 6 or 8 ohm minimum.

Actually early transistor designs used an output transformer, and so the requirements were similar to valves.

 

Also, speaker impedances used to be 16 ohms or 8 ohms commonly.  4 ohms came in mostly with cars I think, due to the need for more power from low (12V) power sources.

[Ittaku]

9 minutes ago, HypnoToad said:

Must be very few as I've never seen a solid state amp with a 6 or 8 ohm minimum.

Not in the AVR space.

 

[aussievintage]

Also, that HMV 8+8 in your signature...  I found some specs

 

* Peak Power 44 Watts 2x8w RMS
* Amplifier Response 50Hz - 20kHz
* Balance Control Range 8 Decibels
* Bass Control Range +/- 10dB at 50Hz
* Bass Control Range +/- 13dB at 10Hz
* Bass, Treble & Balance Control
* Diamond Stylus HV15D
* Cartridge PC31
* Low Frequency Boost
* High Frequency Boosy
* Loudspeaker Impedence 6.2 Ohms at 400Hz
* Auxillary DIN Inputs
* Mono Jack Inputs/Outputs
* Stereo Headphone jack
* Stereo/Mono Mode Switch

 

 

[HypnoToad]

7 minutes ago, Ittaku said:

Not in the AVR space.

 

That's quoting output for a given load, it's not saying that's the minimum speaker impedance. Most Solid State amps will state that you shouldn't go below 4 ohms nominal impedance. And if you connect speakers to the A & B outputs they should not be 4 ohms as this will create a 2 ohm load.

[HypnoToad]

10 minutes ago, aussievintage said:

Also, that HMV 8+8 in your signature...  I found some specs

 

* Peak Power 44 Watts 2x8w RMS
* Amplifier Response 50Hz - 20kHz
* Balance Control Range 8 Decibels
* Bass Control Range +/- 10dB at 50Hz
* Bass Control Range +/- 13dB at 10Hz
* Bass, Treble & Balance Control
* Diamond Stylus HV15D
* Cartridge PC31
* Low Frequency Boost
* High Frequency Boosy
* Loudspeaker Impedence 6.2 Ohms at 400Hz
* Auxillary DIN Inputs
* Mono Jack Inputs/Outputs
* Stereo Headphone jack
* Stereo/Mono Mode Switch

 

Thanks,

Imagine we used to really rock to those, 8 watts per channel, those were the days. I still have a pair of those twin cone Magnavox 6" speakers.

[Monkeyboi]

Speakers have what is known as a "nominal impedance" stated on the label or in the specifications published by the manufacturer. Unfortunately it's just a nominal parameter and as has been be explained in previous replies can vary as the frequency is changed.

 

To be on the safe side and to avoid the possibility of damaging your amplifier (especially if you are inclined to play your music at very loud levels) you should refrain from connecting speakers or combinations of speakers to an amplifier's speaker output terminals that have  a combined impedance lower than that specified by the amplifier manufacturer. 

 

So as an example, if you have a typical HT receiver the manufacturer's user handbook for that unit may say something like "Connect only speakers having an impedance of 6 ohms or higher."  This translated into layman's terms means you can safely operate the amplifier with speakers that have a 6 ohm impedance.  Connecting 8 ohm speakers is okay, but 4 ohms could possibly damage the amplifier if operated at high volume levels for an aextended period.  I will hasten to add that this is a very generalised statement and no doubt depending on the amplifier there maybe a little or lot of latitude regarding how the amplifier will perform with speakers of a lower impedance.

 

If you are contemplating buying your speakers from a reputable hi-fi dealer it's probably worth discussing this with them. Most good dealers will have experienced competent staff that will be able to advise you if the speakers you are thinking of buying will work with the receiver you currently have.

 

BTW, you might get more informed replies if you let us know what brand and model of receiver you have and what speakers you are considering to purchase.  There a re many very experienced members here that I'm sure will be able to provide good advice.  Good luck with your purchase and enjoy the music.

 

Cheers,

Alan R.

 

 

Edited September 13, 2019 by Monkeyboi
typo

[Monkeyboi]

31 minutes ago, Ittaku said:

Not in the AVR space.

 

Ah, that looks like a page from a Sony HT receiver. STR-DN860 ???

 

In replying to this thread I grabbed the handbook for a STR-DN1080 I just happended to have in a drawer behind me.  As I skimmed through the section on connecting speakers I couldn't find any mention of minimum speaker impedance which IME is a bit unusual for Sony because the handbooks for some ot their earlier ES receivers was quite specific on the topic. However as you and I know, sometimes you have to read between the lines to actually find the information you are looking for.  In his case buried in the specifications.  Although it doesn't specifically say "....don't connect loads of less than 6 ohms impedance...", I wouldn't anyway.

 

Some receivers will have the information regarding speaker impedance printed on the back panel.

 

Cheers,

Alan R.

 

[davewantsmoore]

3 hours ago, Maui waui said:

wondering what’s impedance that’s shown on speakers label?

The average impedance of the speaker.

 

3 hours ago, Maui waui said:

I imagine should be same value of the one shown on the receiver

The amplifier should specify a minimum, or range (minimum to maximum) of impedance that it is designed to drive.

 

Don't connect a speaker which is lower than the minimum (or if a range is specified, not outside the range).

 

3 hours ago, Maui waui said:

what happen if you plug a speaker with different impedance value?

It's a complex question  (pardon the pun for any amplifier or speaker nerds).   

 

For a typical amplifier/receiver like you have ......   Stay above the minimum and/or within the range .... and basically "nothing happens... everything works fine".

 

Go outside the range?  Poor performance.... maybe broken receiver.

[Maui waui]

Thanks for the knowledge boys I definitely didn’t know any of it.. not clear every part but understand most of it.

So I have a receiver 

 philips 22ah 692 / 45 doesn’t display the impedance value and I’m looking for some bookshelf speakers.. I was looking at some celestion Ditton(8ohm).. what you reckon?? How much should minimum invest in speakers to feel it?

thank