Why 4 ohm or lower instead of 8? [Archive] - Audio & Video Forums

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GMichael
05-17-2005, 01:48 PM
I see a lot of very high end speakers that are 4 ohm. What is the advantage other than the extra volume? Doesn't the THD go up with these lower loads? And if 4 ohm is "better" then why do most (if not all) Sound Lab Products speakers still use 8 ohms? It's not like these are cheap either.

nightflier
05-17-2005, 02:05 PM
I see a lot of very high end speakers that are 4 ohm. What is the advantage other than the extra volume? Doesn't the THD go up with these lower loads? And if 4 ohm is "better" then why do most (if not all) Sound Lab Products speakers still use 8 ohms? It's not like these are cheap either.

I'm no expert, but it's my understanding that because of the potential for higher THD in these speakers, they are more expensive to design and manufacture. I don't think there is any other difference in performance or quality, but I'm no engineer. As far as what speakers are 4 or 8 ohm, it's been my experience that it's more an issue of geographic standards than anything else. In Europe, most speakers are 4 ohm, and it's been that way for a while. In the US, the 8 ohm variety is more prevalent. I imagine the far east is split between the former british colonies being force-fed 4 ohms and the rest pushing 8.

If you go back far enough, it probably goes back to that whole inches/centimeter debate (friggin' Frenchies, who has a 1 cm thumb, anyways?)
:D

JohnMichael
05-17-2005, 02:14 PM
I remember my first pair of speakers, the Smaller Advents, were designed to be 4 ohm because they were inefficient. They were designed to have the same bass as the Larger Advent in a smaller cabinet. Henry designed them to be 4 ohm to pull more watts out of the electronics of the day.

topspeed
05-17-2005, 02:21 PM
I see a lot of very high end speakers that are 4 ohm. What is the advantage other than the extra volume?Huh? What do ohms have to do with spl's? Are you confusing load ratings with efficiency ratings? i.e. 90dB/1w/1m

Doesn't the THD go up with these lower loads?On amps? Usually, yes. Is it audible? Depends on the amp.
And if 4 ohm is "better" then why do most (if not all) Sound Lab Products speakers still use 8 ohms? It's not like these are cheap either.The nominal ohm ratings on speakers is directly related to the transducers chosen by the engineer to ultimately derive the sound they are looking for. Generally, panels are tougher to drive than normal dynamic designs. However, there is no inherent benefit to designing a speaker around a 4 ohm nominal rating versus 6, 8, or whatever ohm. If anything, designers will try to avoid lower ohms as it makes the speaker less universal in which amps to pair them with.

RGA
05-17-2005, 02:59 PM
to answer your question NO 4 ohms is not better. Often I see 4 ohm speakers which are typically lower efficient and difficult to drive. Many speakers including my old B&W DM 302 were rated as 8 ohm speakers but had a minimum impedence (requiring more power) of 4 ohms.

Think of a speaker's impedence as a bucket and the amplifier as a well. If the amplifier is 8 ohms 50 watts and it's chugging along driving a speaker that is playing flute music at 8 ohms all is well. when the impedence dips in half to 4ohms say when a big percussion is hit at low frequencies then the speaker will demand 100 watts when the amp may only be able to produce 70 into 4ohms...this is really way ovelry simplistic. Some amplifiers like mine are exactly the same in 4 ohms as they are into 8 ohms. Some makers advertise that their amps double exactly to four ohms -- some think this is good --- Not necessarily so. Class A amplifiers often lose power going dwn into 8 ohms and ultimately many myths get created -- typically by makers who use cheap parts.

The "reason" is that a lot of speaker makers feel you need to sacrifice efficieny and sensitivity in order to get bass response...partially that was true because a lot of high efficiency speakers were horns and they could play VERY loud with very little power but usually didn't go much below 50hz and were gigantic. Fast forward and they started making speakers that were less sloppy sounding had deeper bass though not necesarily much deeper (which is interesting) were low efficient requiring way more watts (watts is easy to sell as volume -- it isn't) and the speakers could be made smaller. Then there are speakers that have deep bass, ARE high sensitive are not gigantic and can play pretty darn loud and sound very good to boot. These are speakers I prefer.

It is also generally known that high efficency speakers to do well COST a lot of money require a lot of work to design and to test -- it is far cheaper to overdamp a box and requires a lot less time. Most manufacturers want to make money and they want to increase profits so using cheap garbage and cloaking in nice looking cabinets and advertising the crap out of it is the best way to make a killing in this or any industry.

The issue of watts volume power and quality has been so subverted over the years that you can now buy $200.00 JVC Boomboxes that claim 400-600 watts(whatever that means). My stereo puts out 10 watts. After running the demo you will never worry about the spec sheet printed watts ever again -- mine will blow you into next week and the JVC will not. This article may help http://www.republika.pl/mparvi/300b.htm

GMichael
05-18-2005, 07:16 AM
Thank you all for your replies. Plenty here to let sink in.

Top, what I meant by more volume at lower loads was that I have seen specs on receivers that say, (X) number of watts at 8 ohm, and (X+Y) at 6 or 4 ohm. I just assumed that more volume would be the result.

kexodusc
05-18-2005, 09:00 AM
Volume isn't necessarily a function of whats from the amp/receiver, but a combination of that and the efficiency with which the speaker converts electrical energy into sound.
There are some advantages in terms of bass response to having a nominal 4 ohm (or less speaker), but there's many ways to skin a cat, and ohms by itself isn't determining factor in speaker design.

Despite RGA's evil corporate conspiracy theory about the wicked capitalist companies out to steal your money, high efficiency speakers aren't any better or worse than less efficient speakers in terms of dynamics or sound quality (all personal preferences aside). Though they do present less difficult loads on amplifiers which IMO is a very good thing, but moot if the amp is up to the task anyway. Given the relatively low cost of additional power though, it's not always a big factor. I'd be curious to know if the cost of adding efficiency to a driver is lower than adding power to an amplifer...In all honesty I suspect it is, and I personally feel this allows you to spend more money on quality amplification rather than just high quantity amplification.

One school of thought in favor of low impedance speakers is that you'll often see less volatile impedance swings, which can be beneficial. Some speakers are designed intenionally as 4 ohm speakers for either improved efficiency or because of their expected use in series networks (resulting in an 8 ohm nominal speaker system).

For most people, the only time they have to worry about ohms is to make sure their amplifier/receiver can handle the load.

E-Stat
05-19-2005, 05:37 AM
I see a lot of very high end speakers that are 4 ohm. What is the advantage other than the extra volume?
I've yet to see any high end speaker designer "tout" their selection of impedance as having any intrinsic advantage or not. I think many are 4 ohms simply because they can be.


And if 4 ohm is "better" then why do most (if not all) Sound Lab Products speakers still use 8 ohms? It's not like these are cheap either.
Since you mention Sound Labs, many owners (including me) use tube amps that by and large are not happy with low impedance loads and do better with the higher damping factor.

rw

GMichael
05-19-2005, 10:26 AM
Thanks,
The main reason I was asking is because I want to upgrade my front speakers to a pair of SoundLab Dynastats. My receiver is rated for 6 or 8 ohms only, so these look like a good fit for me. They are 8 ohms. Most of the talk I have seen about "good" speakers seems to be centered around 4 ohms and I wanted to make sure that these measure up even though they are 8 ohms.
Has anyone had a chance to hear these or compairable electrostatic speakers? What are your thoughts?

Florian
05-19-2005, 12:19 PM
Well i would like to add a experience that happend to me recently. My speakers are naturally 1ohm and are thus a pain to drive. I do have the option to rewire them to 4ohm. Since i am thinking about buying two Ampzilla 2000 amplifiers which dont like 1ohm loads it seemed like a good idea. Once we rewired them, they lost almost all their magic. It was like a different speaker and i quickly changed it back to 1ohm and will just use my current AMP. So i think that a lot has to do with the design of the speaker. Also i think it depends if the company is wiring the drivers in series. VMPS does so on the midbass drivers. They represnt a 8ohm load each, but since they are wired in series they drop to 4ohm.

-Flo

GMichael
05-19-2005, 01:08 PM
"They represnt a 8ohm load each, but since they are wired in series they drop to 4ohm."

Typo? You mean parallel?

Have you heard or know anyone who has heard the SoundLab Dynastats? Or any other Soudlab speakers?

Florian
05-19-2005, 02:37 PM
Yes, sorry that was a typo. I personally dont know anyone who has the Soundlabs. But a good place to look is the Audio Asylum and the Virtual Systems on Audiogon.

-Flo

topspeed
05-19-2005, 03:27 PM
Have you heard or know anyone who has heard the SoundLab Dynastats? Or any other Soudlab speakers?
nt....

E-Stat
05-19-2005, 05:53 PM
Or any other Soudlab speakers?
I happen to be the lucky owner of a pair of U-1s. As for electrostats in general, I have owned one pair or another for nearly thirty years. While the big brothers to the Dynastats operate full range, they share the same panel technology. So what can I say about them?

They aren't there. Despite their size, they disappear acoustically when you cue the music. They exhibit a profound top to bottom transparency not bettered by quite a few speakers in my experience including MG 20.1s, Avalon Ascents, and Alon Grand Exoticas. I have never heard qualitatively better bass although the 20.1s are darn close. If they have an Achilles heel, it is with their low efficiency. It takes some real power to produce concert levels in a large room. On the other hand, they are low level resolution champs and sound unusually loud for a given measured output. The results you get are directly proportional to the finesse of the source and amplification stages.

The Dynastats have less panel area and use a dynamic woofer for the low end. I would imagine that from the mid bass on down, they don't share quite the same clarity or efficiency, but the midrange and top should have the same delicate, ultra low distortion signature of the better electrostats. If you are a detail freak and/or cherish acoustic music, then I would give them a serious listen. They are probably not particularly well suited, however, for high level "blow-up-a-helicopter" HT duty though.

<a href="http://forums.audioreview.com/showpost.php?p=82842&postcount=39">My U-1s</a href>

rw

GMichael
05-20-2005, 05:17 AM
U-1's huh? Nice! Not in my budget though. Maybe some day down the road. But I would also need amps to drive them. Thanks for the review. You said everything I was hoping to hear. Hopefully my Yamaha can drive the Dynastats. I don't need extreemly high levels of output, just clean clear sound. Do you use the Marquee for your center channel? Do you HT at all or strickly 2 channel?
I emailed SL a couple of days ago to get a location near me so I can hear for myself. No reply yet. May need to follow up with a call.


Flo,
Thanks for your lead. I never heard of them but I will research and learn.

Glen B
05-20-2005, 09:14 AM
I see a lot of very high end speakers that are 4 ohm. What is the advantage other than the extra volume? Doesn't the THD go up with these lower loads? And if 4 ohm is "better" then why do most (if not all) Sound Lab Products speakers still use 8 ohms? It's not like these are cheap either.

The lower impedance makes more power available [i.e. from a capable amp] to compensate for the speaker's lower sensitivity. No other motives.

Florian
05-20-2005, 09:21 AM
Makes sense. I have the early model from the Scintilla which has the option for 4 or 1 ohm. The later ones were all only 1ohm. At 1ohm my Krell delivers close to 1.8kw per channel. At 4ohm only 440wpc. My speakers are very very power hungry, especially since they have a very low 74db sensitivity. But are you sure its power and not current?

-Flo

E-Stat
05-20-2005, 09:38 AM
U-1's huh? Nice! Not in my budget though.
Periodically either SL or dealers will sell factory fresh refurbished models. I went that route and got all brand new guts (cores and backplanes) and saved around $10k. Only the steel frame and backplane enclosures are used.


Do you use the Marquee for your center channel? Do you HT at all or strickly 2 channel?
I have a separate HT system that is adequate for that task using conventional box speakers.

rw

kexodusc
05-20-2005, 10:02 AM
4 ohm speakers are not necessarily any less or more efficient than 8 ohm speakers. Nominal Impedance and efficiency aren't related as such.

jt1stcav
05-21-2005, 07:58 AM
My Triangle Electroacoustique Zephyr 2-way towers (45Hz-20kHz @ 4 ohms 1W/1M) are realitively efficient at 91dB and mate quite nicely with my lowly 8 watt per side BEZ Model T3B Class-A 300B SET power amp (with 8 & 4 ohm taps). They sound dynamic and full-bodied, with clear highs and decent bass (still need a sub to add the organ's lowest octave missing from the Zephyrs), and will comfortably play over 90dB before any clipping occurs.

FWIW...