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Thread: Why lower impedance? |
    
Bronze Member Username: Eieiei0101x
Post Number: 63
Registered: Jul-05
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| Posted on Wednesday, October 05, 2005 - 05:00 pm: |
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Why is it that most of the finest speakers work at 4 ohms vs most budget speakers work at 8?
Is there any advantage in sound quality in lower impedances ?
Thanks a lot |
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Gold Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 5991
Registered: May-04
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| Posted on Wednesday, October 05, 2005 - 09:00 pm: |
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You must be looking at different speakers than I am.
There is no direct advantage to the speaker running at lower impedances unless the mated amplifier is designed to operate into that load. A transformer coupled amplifier wired to the four Ohm tap or a Class D amplifier designed for four Ohm loading will prefer a lower impedance speaker for the flattest frequency response and highest damping factor. Most direct coupled, solid state amplifiers prefer to operate into an eight Ohm or higher load. It is, of course, the total amount of impedance variation along with the phase angle of the entire speaker system which determines whether an amplifier is happy running any given load.
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Silver Member Username: Devils_advocate
Post Number: 470
Registered: Jul-05
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| Posted on Wednesday, October 05, 2005 - 11:06 pm: |
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"A transformer coupled amplifier wired to the four Ohm tap or a Class D amplifier designed for four Ohm loading will prefer a lower impedance speaker for the flattest frequency response and highest damping factor."
I thought that the damping factor was the speakers impedance divided by the amplifiers output impedance, eg the higher the impedance of the speakers, the higher the damping factor? |
Gold Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 5996
Registered: May-04
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| Posted on Thursday, October 06, 2005 - 12:01 am: |
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On paper, or when no signal is present in an amplifier, that's a very convenient way to look at the relationship. In the real world of ever changing frequencies along with voltage and current delivery into an ever changing impedance (capacitive, inductive and resistive) load, there is more to the story.
http://www.classic-audio.com/marantz/mdampingfactor.html
http://www.trueaudio.com/post_013.htm
I used the term "damping factor" as a convenience since I felt most people would be familiar with the term. As in the second article, I probably should have used the concept of the amplifier's ability to damp (or control) the motion of the speaker system. Sorry for the confusion.
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Silver Member Username: Cheapskate
Post Number: 432
Registered: Mar-04
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| Posted on Thursday, October 06, 2005 - 04:20 am: |
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i'd bet that "most of the finest" speakers are really 6-8 ohms, but some of them are 4 ohms.
4 ohm speakers are very amplifier fussy. it makes sense that many of the fussiest "cost no object" speakers also require cost no object amplification to match.
typical speakers and amps are designed around the 8 ohm standard. my 1st pair of real speakers were JBLs rated at 6 ohms.
at all price levels, i bet that at least 80% (probably closer to 95%) of speakers are 8 ohms.
8 ohm loads are generally attributed with having tighter more controlled bass. most amps prefer higher impedence than lower. cheaper speakers that have 8 ohm loads are more "universal".
cheap speakers that require $500 in high current amplification doesn't make sense does it? |
Bronze Member Username: Eieiei0101x
Post Number: 64
Registered: Jul-05
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| Posted on Thursday, October 06, 2005 - 10:43 am: |
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I will read in detail the articles sionce i did not understand much but I consider Dynaudio and Totem good speakers way above average performance work at 4 ohms, so as long as their are matched with average 500 to 1000 U amps they have no significant advantage vs 8 ohms speakers?
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Gold Member Username: T_bomb25
Dayton,
Ohio
United States
Post Number: 1080
Registered: Jun-05
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| Posted on Thursday, October 06, 2005 - 11:14 am: |
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Eduardo that statement Budget just made doesent make any sence,most of the best speakers on the market are 4 ohms speakers.The test bench generally reveals that most of the so called best speakers are 4 ohm loads even if they are rated 8 ohms from the manufacture. |
Gold Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 5999
Registered: May-04
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| Posted on Thursday, October 06, 2005 - 11:18 am: |
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"8 ohm loads are generally attributed with having tighter more controlled bass."
Explain, please.
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Gold Member Username: Dmwiley
Post Number: 1232
Registered: Feb-05
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| Posted on Thursday, October 06, 2005 - 11:30 am: |
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Test bench smest bench. To claim that most of the best speakers are 4 ohm is ridiculous on its face. Listen to a broad array of speakers and you will see what I mean.
The MOFO has spoken. |
Bronze Member Username: Eieiei0101x
Post Number: 65
Registered: Jul-05
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| Posted on Thursday, October 06, 2005 - 11:40 am: |
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What do you mean by Fussy?
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Silver Member Username: Devils_advocate
Post Number: 475
Registered: Jul-05
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| Posted on Thursday, October 06, 2005 - 11:48 am: |
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Interesting links there Jan. The second one particularly offers insights into why a few other overlooked aspects of the system are important too. |
Gold Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 6003
Registered: May-04
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| Posted on Thursday, October 06, 2005 - 12:25 pm: |
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Interesting, but I wonder where the author came up with a speaker cable with 0.25 Ohm cable. I assume the high value is used merely to make the point.
http://sound.westhost.com/cable-z.htm
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Gold Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 6004
Registered: May-04
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| Posted on Thursday, October 06, 2005 - 12:31 pm: |
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As I've looked at the original question again, "Is there any advantage in sound quality in lower impedances?", I've decided the answer could be given as; yes, depending.
Obviously when a speaker designer decides whether the speakers will be hooked up in series or in parallel, there is an intent in mind. Additionally, the effects of a crossover connected in series or in parallel can be quite different. I think, overall, you have to assume the designer saw a benefit to operating the speaker system at a lower impedance. What that benefit would be would vary with each design to some extent and the only way to justify the decision would be to ask the designer why the choice was made.
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Gold Member Username: T_bomb25
Dayton,
Ohio
United States
Post Number: 1084
Registered: Jun-05
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| Posted on Thursday, October 06, 2005 - 12:37 pm: |
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Most companies arent being honest with their impediance loads,B&W for example nearly rate all their speakers at 8 ohms put them on the test bench and it will say otherwise they are 4 ohms atleast and most of the time they have dips down to 2 ohms and below and generally up under 200htz. |
Silver Member Username: Devils_advocate
Post Number: 477
Registered: Jul-05
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| Posted on Thursday, October 06, 2005 - 12:51 pm: |
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~20 Feet of 18 gauge wire would do the trick for 0.25 ohms. I doubt too many audiophiles would stoop to that though. 0.1 ohms is probably fairly common though. |
Gold Member Username: Dmwiley
Post Number: 1234
Registered: Feb-05
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| Posted on Thursday, October 06, 2005 - 01:04 pm: |
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"Most companies arent being honest with their impediance loads,B&W for example nearly rate all their speakers at 8 ohms put them on the test bench and it will say otherwise they are 4 ohms atleast and most of the time they have dips down to 2 ohms and below and generally up under 200htz."Oh I see, Tawaun. Consumers should just ignore the company's specs and pull out the work bench and test for real ohmage. You're an idiot.
The MOFO has spoken. |
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| Posted on Thursday, October 06, 2005 - 06:18 pm: |
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"Most companies arent being honest with their impediance loads,B&W for example nearly rate all their speakers at 8 ohms put them on the test bench and it will say otherwise they are 4 ohms atleast and most of the time they have dips down to 2 ohms and below and generally up under 200htz."
You should note that when B&W list their speaker's impedence, they also list the minimum impedence figures also.
Why don't you try being 'honest' and tell things as they are?
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Silver Member Username: Stu_pitt
NYC,
NY
Post Number: 640
Registered: May-05
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| Posted on Friday, October 07, 2005 - 06:45 pm: |
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"Consumers should just ignore the company's specs and pull out the work bench and test for real ohmage."
It got deleted when someone else asked it, and I never saw the answer, so I'll ask -
What is Ohmage? |
Gold Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 6036
Registered: May-04
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| Posted on Friday, October 07, 2005 - 08:39 pm: |
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http://product.ebay.com/Paying-Ohmage_UPC_651811006127_W0QQfvcsZ1226QQsoprZ34479 53
http://www.ohmage.ca/
http://www.skylinx.com/mtd/greasecat/vwp/
http://www.infoplease.com/ipd/A0565456.html
http://www.infoplease.com/thesaurus/ohmage
http://www.diyaudio.com/forums/showthread.php?postid=129961
http://www.talkbass.com/forum/archive/index.php/t-157123.html
Now, what is fairy dust?
(No rude comments, please. Paul is gone, let's not get started again.)
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Silver Member Username: Touche6784
USA
Post Number: 627
Registered: Nov-04
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| Posted on Saturday, October 08, 2005 - 12:50 am: |
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what happened to him? |
Gold Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 6049
Registered: May-04
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| Posted on Saturday, October 08, 2005 - 12:53 am: |
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Only the administrator knows for certain. It's kind of like in "The Prisoner" when #6 tries to escape the island. |
Silver Member Username: Audioholic
Post Number: 179
Registered: Apr-05
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| Posted on Saturday, October 08, 2005 - 07:34 am: |
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Lets hope speaker manufacturers are designing for parallel hookup rather than series (though many cheap recievers wire speaker "b" in series). In series the speaker is no longer being driven by the amplifier but rather by the driver preceeding it, which is not an ideal output impedence and is contantly fluctuating in it's own impedence and is frequency dependant. Think distortion passed from driver to driver, thereby becoming distorted distortion. Nice. |
Gold Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 6052
Registered: May-04
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| Posted on Saturday, October 08, 2005 - 11:50 am: |
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I know of no receivers with speaker selectors wired in series at this point in time. Most inexpensive receivers have even given up on speaker selectors as a waste of a buck that could go to marketing their junk product. The speaker switching is now left to a dedicated switch box in most cases which are almost always wired in parallel.
I haven't looked closely at the receiver market for several years. Sony was the last receiver line which I knew of that was wired in series, and they discontinued that practice in the 1990's. What receiver lines are now wired in series?
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Gold Member Username: Jan_b_vigne
Dallas,
TX
Post Number: 6053
Registered: May-04
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| Posted on Saturday, October 08, 2005 - 12:02 pm: |
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Maybe I misread your post, PB. If you are implying that the actual drivers hooked in series within the speaker system are a bad idea, I would have to disagree. There are reasons for designing a series hook up, a parallel-series hook up and placing a Xo in series with the drivers. Just as there are reasons for not hooking the drivers in parallel or bi-wiring the system.
I know your stance on correct Xo design, and I'm not trying to be rude, but I would hope you are not advocating parallel hook up of the individual drivers as "the only correct way" to design a speaker.
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