what's the different between 4 and 8 ohms speakers? [Archive] - Audio & Video Forums


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08-30-2004, 05:20 PM
i have been looking for a reciever that has the option of 4 ohms output for my speakers. So far I have been looking at NAD is there any other reciever brand with that option?

N. Abstentia
08-30-2004, 06:08 PM
Do you already have 4 ohm speakers?

08-30-2004, 06:32 PM
yeah blueroom minipod

N. Abstentia
08-30-2004, 08:57 PM
Yeah you'll definitely need something stable to 4 ohms. Along with NAD, Rotel should have no problems at 4 ohms.

08-30-2004, 09:53 PM
Arcam is another.

This site might help - the magazine is much more up to date - the Arcam AVR 300 has been getting good talk - haven't heard it myself. http://hifichoice.co.uk/review_list.asp?category=AMP&subcategory=MULTI

08-30-2004, 11:53 PM
I agree with these guys but If you want an answer with a bit more elaboration...

The speaker ratings you mention are the relative or average impedance of the speakers. Impedance, as the word suggests, is a form of resistance -- to "impede" or hinder. Put simply, Impedance is a "frequency dependant" resistance. As frequency changes the measure of resistance changes too. Unless an audio speaker is only going to reproduce a single frequency, such as a test tone, the resistance of the speaker will change with the varied frequencies of the musical material: But it is possible to give speakers an average impedance rating. So as you asked, "what's the difference between 4 and 8 ohm speakers?" the 4 ohm speaker offers less relative resistance than the 8 ohm speaker does. What practical value does this information provide for you? It may seem backward but the speaker with a lower impedance rating is "relatively" harder to drive by and amp or receiver than the speaker with a higher impedance rating. Why? In order to understand that, you have to understand what the speaker is impeding. Electrically, the speaker is resisting the flow of electrical current. The higher the rating, the lesser amount of current draw on the amp's power supply: The lower the rating, the greater amount of current draw on the amp's power supply. You can think of it in terms of water systems if that helps... a small diameter pipe has more resistance (in the form of friction and reduced capacity) than a larger diameter pipe. But because the large diameter pipe has less resistance to flow and greater capacity, it must be supplied by a larger reservior. In other words it places a greater demand on its source. Hopefully that make sense to you, but if not, let me know and I'll try to explain it differently.

As a practical matter, if you're using these speakers in a 2 channel stereo setup and don't intend to listen at very loud levels, most decent quality receivers will drive them adequately; especially if you use them with a sub. Since they are only rated down to 100 hz, a sub is going to be a good idea anyway.

The brand names that have been mentioned in the other posts tend to offer good current capacity into lower impedance loads so there is certainly nothing wrong with those recommendations. But as I said, if you're using these for "stereo" listening at light to moderate volume levels, many mass market receiver brands will provide all the power that you need. If you are thinking about using a set of five for surround sound, then that would probably NOT be a good idea.

One other thing to watch for is an impedance setting switch which is sometimes available on receivers. The thing you need to now about this switch is that it is a protective device only. It limits the current draw on an amp to protect receiver and/or speakers but does not do anything to improve the sound of lower impedance speakers -- in fact, it can negatively effect sound. You are much better off finding a receiver which post good "watts per channel" numbers into lower impedance loads than buying a receiver simply because it has this switch.

Like I said, there was nothing wrong with the previous recommendations in the other posts. But the way you phrased your question led me to believe you might be interested in more of an explanation of what these ratings are all about and how it effects receiver choices. I hope I didn't make it more confusing for you.


09-01-2004, 03:54 PM
thank you so much Quagmire! that explains a lot!

09-01-2004, 07:51 PM
My pleasure. Glad to be of service to you. I'm still curious... are you looking strictly for a stereo receiver or will you be purchasing a home theater receiver? Or maybe you're looking for a home theater receiver but want these particular speakers for your 2 channels stereo listening? Are you considering a sub or do you already have one? I'm interested in some of the details you haven't revealled yet, because it could mean a great deal of difference in how much money you need to spend and the overall quality of what you end up with. If you don't mind sharing this information it would help with making very specific recommendations.


09-02-2004, 09:47 AM
4ohms of course ----> LOL couldn't resist that. Hehehehehehehehe.

09-03-2004, 07:39 AM

I just got a NAD T-753 and I already have 2 pairs of blueroom mini pod but now im looking for a subwoofer and a center channel. If you have any good recommendation please let me know. i was looking at b&w sub for about 350 at a local audio shop. thank you. anyway have you ever heard anything about the blueroom minipod? when i plugged mine in it sounds unclear and is there any difference between optical and coaxial? coz im using optical right now

Norm Strong
09-03-2004, 03:20 PM
4 ohms

Norm Strong
09-03-2004, 03:22 PM
i have been looking for a reciever that has the option of 4 ohms output for my speakers. So far I have been looking at NAD is there any other reciever brand with that option?

Panasonic and Yamaha receivers will handle 4 ohms speakers. The Panasonic HE100 is selling for only $200.

09-04-2004, 09:42 AM

I am a bit concerned that you are planning to use these speakers all the way around in a surround system. As Norm said, there are other receiver brands that will drive 4 ohm speakers, but what is not being said is that many times if you check the owner's manual it will advise against using them for ALL speaker positions. In other words, it's okay to use them exclussively for the mains or for the surrounds but not for all speaker channels. In a receiver, where there is usually only a single shared power supply, it may be possible to overdraw current from the power supply if only 4 ohm speakers are used, especially at anything near reference levels. I would strongly advise you to look through the manual for your receiver to see if it contains any such warning; you might even want to give NAD a call to ask. At the very least I would encourage you to use caution and be on the lookout for overheating and distortion. The receiver may be fine a majority of the time but could be in trouble for instantaneous high demand loads or spikes which can occur with musical and movie material. I cautioned you about this in my first post and I just want to restate my concerns again.

I don't know very much about the blueroom speakers: I take it that they don't offer a center channel speaker? The best recommendation I can make is to verify that the mini pod speakers are video shielded, and if so, to use an additional one in the center speaker location. If this is feasible, it will provide you with certain sonic advantages over the typical center speaker configuration anyway (I won't go into the details of that for now.). If this is not feasible and/or they are not video shielded then you will have to make an extensive search to find something that will work well with them or forgo using a center channel speaker at all -- something which I do not recommend. Exactly how did you arrive at deciding on this particular speaker anyway? Price? Performance? Style? Bottom line... these may not be your best choice if Home Theater (Movies) is your prime interest. Not trying to burst your bubble or rain on your parade, but that's just the truth as I see it. Only you know if you're locked into these or not, but you've already mentioned that they sound "unclear" to you so if you're just now getting to audition them, it sounds like you might not be that pleased with them anyway.

As far as a Sub recommendation goes, there are many choices and it mostly depends on how much you are willing to spend to get the performance level you require. If you go ahead with the blueroom mini pods, you will definitely want to invest in a good sub AND run all of your speakers as "small" from the receiver. I would actually advise you to post a seperate thread requesting sub recommendations as I think you will get more responses and better advice.

The question regarding Optical -vs- Coax is one which is well suited for the new "Audio Lab" board. There are certain advantages to Coax which have nothing to do with audibility, however there are some audio enthusiast who will tell you that Coax is audibly superior to Optical -- namely, they will tell you that it sounds "warmer" and less digital. You will have to decide for yourself how much credibility to give their advice and whether you can afford their advice anyway. I simply can't afford to be a true blue "subjectivist". My advice is that for your purposes, it make no difference at all, but I do like to encourage people to experiment -- decide for yourself -- you tell me if there is a difference.