# A couple of electronics questions **URL:** \ **Category:** Factual Questions\ **Created:** [December 16, 2010, 3:43pm UTC](https://boards.straightdope.com/t/a-couple-of-electronics-questions/564365 "2010-12-16T15:43:35Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![squeekster](https://avatars.discourse-cdn.com/v4/letter/s/779978/32.png) [@squeekster](https://boards.straightdope.com/u/squeekster)\ **Post date:** [December 16, 2010, 3:43pm UTC](https://boards.straightdope.com/t/a-couple-of-electronics-questions/564365/1 "2010-12-16T15:43:35Z")
First of all, when speaking of surround sound, what does “5.1” or “7.1” mean? I assume that the “5” or the “7” means the front R, L, and center speakers plus the rear R and L speakers. But what does the “.1” refer to? The sub woofer? Second, I am considering buying a surround sound amp to be used with speakers I already own. In connecting them up, do I really _need_ to connect a sub woofer at all? The four main speakers I already have would put as much or more bass than a sub woofer would. I’m just a little concerned that if I leave the sub woofer hook up on the amp empty, it will cause the amp to “think” there is an open circuit or something and keep it from working. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [December 16, 2010, 3:47pm UTC](https://boards.straightdope.com/t/a-couple-of-electronics-questions/564365/2 "2010-12-16T15:47:02Z")
> [@squeekster](#): > > First of all, when speaking of surround sound, what does “5.1” or “7.1” mean? I assume that the “5” or the “7” means the front R, L, and center speakers plus the rear R and L speakers. But what does the “.1” refer to? The sub woofer? Yes, the .1 refers to the subwoofer. Real fanatics have .2 systems and their subwoofers actually operate in stereo. > [@](#): > > Second, I am considering buying a surround sound amp to be used with speakers I already own. In connecting them up, do I really _need_ to connect a sub woofer at all? The four main speakers I already have would put as much or more bass than a sub woofer would. I’m just a little concerned that if I leave the sub woofer hook up on the amp empty, it will cause the amp to “think” there is an open circuit or something and keep it from working. If your speakers are full-size, you may not _need_ a subwoofer, no. Still, in my experience, you may find that you’ll get better performance out of them if you do, though, because you’re sending the very lowest frequencies to a speaker that _only_ handles those frequencies, allowing your mains to provide cleaner mid-frequencies. You can adjust the crossover point to your liking so that the balance is good for your gear. If you’re going to be watching movies, my one piece of advice would be to be sure to get a good center speaker. It really enhances the clarity of dialogue like nothing else can. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [December 16, 2010, 3:51pm UTC](https://boards.straightdope.com/t/a-couple-of-electronics-questions/564365/3 "2010-12-16T15:51:47Z")
> [@](#): > > Yes, the .1 refers to the subwoofer. Real fanatics have .2 systems and their subwoofers actually operate in stereo. given low frequency content is omnidirectional and nearly always mixed monaural, I don’t think they’re really doing what they think they are doing. > [@](#): > > Second, I am considering buying a surround sound amp to be used with speakers I already own. In connecting them up, do I really _need_ to connect a sub woofer at all? no, but if your main speakers are able to play low enough, you may have to set them as “large” speakers in the receiver/processor setup, depending on how the settings are done in your equipment. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [December 16, 2010, 3:55pm UTC](https://boards.straightdope.com/t/a-couple-of-electronics-questions/564365/4 "2010-12-16T15:55:42Z")
> [@jz78817](#): > > given low frequency content is omnidirectional and nearly always mixed monaural, I don’t think they’re really doing what they think they are doing. Hence my use of “fanatics” rather than “experts.” 😉 ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [December 16, 2010, 3:56pm UTC](https://boards.straightdope.com/t/a-couple-of-electronics-questions/564365/5 "2010-12-16T15:56:26Z")
fair enough 🙂 ---
**Author:** ![Munch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/munch/32/5281_2.png) [@Munch](https://boards.straightdope.com/u/Munch)\ **Post date:** [December 16, 2010, 4:24pm UTC](https://boards.straightdope.com/t/a-couple-of-electronics-questions/564365/6 "2010-12-16T16:24:40Z")
> [@squeekster](#): > > First of all, when speaking of surround sound, what does “5.1” or “7.1” mean? I assume that the “5” or the “7” means the front R, L, and center speakers plus the rear R and L speakers. But what does the “.1” refer to? The sub woofer? 7.1 is also pretty overrated\*. There are very few movies available in 7.1, and just a fraction of those were ever originally recorded in 7.1 (the last two channels are typically matrixed together in post-production). Your money is much better spent on a subwoofer, which I really really recommend. Use your directional speakers for directional sound - get a subwoofer for the omni-directional lows. \*It’s also pretty hard to find a receiver these days that doesn’t output 7.1. However, most receivers will also give you Zone 2 capabilities - so if you want to set up speakers somewhere else in the house (patio, bathroom, kitchen), it’s very handy to have. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [December 16, 2010, 4:49pm UTC](https://boards.straightdope.com/t/a-couple-of-electronics-questions/564365/7 "2010-12-16T16:49:21Z")
[QUOTE=jz78817] given low frequency content is omnidirectional and nearly always mixed monaural, I don’t think they’re really doing what they think they are doing. [/QUOTE] I don’t think there are any consumer surround formats that have stereo LFE channels - with the usual Dolby formats, it’s just impossible to have bass in stereo. However, if you want a LOT of bass, there’s nothing particularly wrong with two subwoofers as long as you take care to locate and phase them properly. Set up incorrectly, you can wind up with very little perceived bass. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [December 16, 2010, 4:54pm UTC](https://boards.straightdope.com/t/a-couple-of-electronics-questions/564365/8 "2010-12-16T16:54:35Z")
> [@](#): > > I don’t think there are any consumer surround formats that have stereo LFE channels - with the usual Dolby formats, it’s just impossible to have bass in stereo. even with normal stereo recordings, the bass is monaural. > [@](#): > > However, if you want a LOT of bass, there’s nothing particularly wrong with two subwoofers as long as you take care to locate and phase them properly. Set up incorrectly, you can wind up with very little perceived bass. using multiple, properly placed subwoofers is also an accepted way to deal with modes in small listening rooms. But the “properly placed” part is key 🙂