Audio Equipment and Home Theater Audio : Stereo question for audiophiles

Stereo question for audiophiles

I'm looking for some help from a speaker-savvy person if possible. I'm in the first stages of slowly building a decent home theater system (I'll be using it mostly to play music, though I'm sure I'll use it for movies too). By first stages, I mean I just got my first piece - a Sony STR-DE998 receiver (120 watts per channel). Currently, it is part of a Frankenstein's monster of a surround sound system. The front, rear and center speakers were taken from an old stereo system I had, and the two side speakers are two really old speakers my dad had lying around. Obviously, I am looking to replace the speakers a little at a time, along with picking up a subwoofer and a turntable.

I guess my question is what should my priority be. Should I get a sub first, or start with the speakers? The sound isn't terrible with the older speakers but it's rather flat, probably because there isn't very much bass due to lack of a sub. I'm looking to be economic, though. Does a powerful receiver mean you don't need as powerful speakers? Is there a correlation at all? I'd like it to get the job done but I don't want to end up penniless for it. I'll probably get a 100-watt sub, since those seem like the only ones you can get for under $100. As far as speakers, I haven't really looked into them yet.

Not sure if it makes a difference, but most of the music I play is through my computer. I have audio cables running from the receiver to my computer's headphone jack. Not sure if that would effect the sound quality as well.

Any suggestions/tips would be helpful.

Oh, I'm sorry. Did I break your concentration?

Re: Stereo question for audiophiles

First, if those are big(ish) stereo speakers, like with 8" or larger woofers, you may not need a subwoofer. Have you configured the receiver for "no sub" and "large" front speakers? That should direct all the bass to the front speakers.

Otherwise, yes, a subwoofer makes a huge impact. I'd suggest 200 to 500 watts RMS if possible, and a 12" or larger sub. Two or more subs makes for more evenly distributed bass in the room (if you locate each sub in a different corner, or one in a corner, another midway along a wall, that kind of thing). I think Hsu and SVS subs are pretty good value. Or, consider building your own; that's often the best boom for your money. Check out the subwoofer forum at diyaudio.com, or the diy speaker forum at avsforum.com On a $100 budget, I'd buy one good 12" (or 15") and use some scrounged power amplifier, like a yard sale stereo receiver or a car amp run from the 12V battery in a computer UPS. Then watch for a good deal on a better power amplifier.

Re: Stereo question for audiophiles

I've configured the speakers (the front speakers are 100 watts) to large and "no sub". Large definitely makes a difference, but there seems to be absolutely no change when I toggle between sub/no sub. When the speakers were attached to the stereo they came with, they distributed the bass very nicely. Now that they are in the new receiver, the sound is much flatter. I will post a link to a craigslist ad I found that has the exact stereo my speakers are from. I can't find it now cause I'm at work and I don't have the model number. It's a Panasonic 5-disc cd player/tape player with 5 speakers (the same 5 I have hooked up to the new receiver now).

Oh, I'm sorry. Did I break your concentration?

Re: Stereo question for audiophiles

That receiver is rated at 110 watts into 8 ohms.
It's the effiency rating or sensitivity rating of the speakers and the Ohm rating you need to look at.
The higher that rating, listed in decibles, the louder the speakers can go on fewer watts. (which means less distortion, clipping and less strain on the receiver) and speakers below 8 ohms need more power to do the same amount of work. So if you find 6 or 4 ohm rated speakers, that have a low sp, say, 84, that amp won't be enough, unless its a small room and you don't turn it up.
I would say get the best speakers you can buy, then like the other poster said, you might not be in a hurry to get a sub, especially a sub of only 100 watts.
A good set of front speakers would walk all over that.

If I had that amp I would look for speakers with sp ratings in the 90's and are 8 Ohm. And then get the best sounding to you, test some of your favorite music.
When you price them, also find out what their partners are in 5.1, because you are later going to need to buy the center and surrounds that match.

Re: Stereo question for audiophiles

Your priority should depend on what matters more to your overall movie experience:

1. Loud bass rumbling from low frequency effects (e.g. explosions, etc.)

2. Clarity of dialogue and overall sound effects mix.

For me, the answer would always be #2... because most of the movies I watch would be pointless without clear dialogue and overall sound.

One important thing you need to know... well two, about bass management in a surround sound system:

During Dolby Digital playback (let's ignore DTS here because the vast majority of soundtracks are mastered in DD not DTS) the LFE channel sends to subwoofer only the frequencies that were encoded in the LFE channel by the sound engineer to begin with. Dialogue is not enhanced by LFE, nor are most sound effects (e.g. someone walking, doors opening, street noise, etc.). The LFE is at the sound engineer's disposal as an "overspill" to handle the lowest frequency sound effects (typically below 80Hz) of such high amplitude that would otherwise heavily tax full range speakers and muddle the sound mix, drowning out dialogue and other critical sound elements... but the lowpass filter having been applied during the mastering process, the resulting LFE output is fixed and limited not just to 120Hz or below, but only those particular sounds that the engineer lowpassed to LFE.

That said, while a home surround processor's bass management cannot change what is in the LFE channel output, it can override what is sent to the subwoofer in ADDITION to the LFE in a few ways... the most common is the LARGE/SMALL selector for your Left, Center, Right and SurL and SurR speakers. If those speakers are all woofer-driven full range speakers typically 5.25" or greater diameter on the primary woofer with 89dB or higher sensitivity, and 90dB or higher dynamic range extending well below 120Hz (the actual hard cutoff for the LFE channel)... then the LARGE setting should be used.

What the SMALL setting does is it applies a lowpass filter to ALL the channels in the DD mix and reroutes their lowest frequencies to the subwoofer to use the subwoofer's internal amp to relieve strain on the main amplifiers and speakers. I never recommend using this setting under any circumstance except where, as previously stated, the speakers are definitely incapable of full range sound.

There's no added sonic benefit to muddling up the mix against what the original sound engineer had in mind when they were in the control room shaping the mix with full range speakers.

As to the other issues:

If you're not in a large auditorium I don't believe that anything above 10 inches and 300 watts is necessary as a subwoofer. Provided the subwoofer's sensitivity is adequate, very little power should be required. I mean, to give you an idea. What's important is proper subwoofer placement. Placing the sub between the center channel and one of the front speakers is recommended by Dolby Laboratories. Granted, frequencies below 250Hz lack coherent phase characteristics... meaning the signal disperses in all directions and is difficult to localize. But, materials can still absorb, entirely obstruct or create unwanted reverberation.

It depends on the engineering of the sub and whether the specs are really accurate, or inflated. To a degree, you get what you pay for, at least up until you start getting into the ridiculous audiophile equipment where additional money doesn't really produce truly discernible benefits proportional to the added cost. At $100, I can expect relatively poor engineering so be prepared for bass that isn't going to sound very tight and coherent... lot of unwanted resonance making LFE sound muddy (all the more reason not to screw it up further using the SMALL setting). I'm not meaning to be a price snob, as I said when you get into "audiophile" equipment there's a lot of smoke and mirrors. But in between... there's noticeably cheap design as you get to the lowest end. In that scenario it's almost preferable to have no LFE than bad LFE.

I will tell you this, I have a KEF PSW-2150, 10 inch 250 watt sub. It sits between my center and front right and fires forward, not downward, with the port firing forward as well. It generates so much sound that in a 10x14 area with the couch 8 feet from the TV, I have to turn the input gain down 50% because it's ridiculously loud.

Regarding your five main full-range channels, your amplifier's actual continuous output for music is probably a lot less than 120 watts per channel. I won't go into the various reasons why, but RMS ratings are a lot of bs... the true continuous output for music and movies, which have very dynamic sound, is probably half that. That said, note that a 3dB increase in sensitivity reduces power requirements by half! In other words, 80 watts into a speaker with 89dB sensitivity will produce the same output as 40 watts into a speaker with 92dB sensitivity!

So the really critical issue, in my mind, is your main five speakers... They should be of adequate power handling, sensitivity and dynamic range (at least 101dB to properly reproduce most film soundtracks).

Please note: Do not use anything other than the STANDARD setting for Dynamic Range Control on your receiver's Dolby Digital decoder settings. Every Dolby Digital soundtrack mastered to DVD has a parameter carrying information about the soundtrack's A-weighted average loudness (LeqA) so that the DD processor in standard mode applies the appropriate degree of both dynamic range compression and dialogue normalization so that from one program to the next, volume doesn't have to be constantly adjusted to make dialogue audible, and that large dynamic changes in loudness do not significantly distort the overall mix.




Nature abhors a moron. -H.L. Mencken
http://www.cinemalogue.com

Re: Stereo question for audiophiles

Regarding your five main full-range channels, your amplifier's actual continuous output for music is probably a lot less than 120 watts per channel. I won't go into the various reasons why, but RMS ratings are a lot of bs... the true continuous output for music and movies, which have very dynamic sound, is probably half that. That said, note that a 3dB increase in sensitivity reduces power requirements by half! In other words, 80 watts into a speaker with 89dB sensitivity will produce the same output as 40 watts into a speaker with 92dB sensitivity

===> On RMS, up to a point. The trouble is, for a 3db gain, you have to double the power. I proved this when using tube power amplifiers for a school dance last year. The first dance I used 32 watts per channel with 102db sensitivity speakers.
The second dance on Halloween, I used 65 watt tube amps, and it most definitely made a difference on the floor, and this was with 700 screaming kids.

You have to enough power to have headroom or you start clipping the amplifier. The hardest material for an amplifier to reproduce is heavy metal and classical and to some extent, bluegrass. I've monitored plate current on a pair of very high power tube amps, (125 watts) and the plate current is always a little higher with classical and heavy metal. Movie soundtracks fall under "classical". However, I will say that I used a 14 watt Bogen tube amp from the 1940's with a 89db center channel, and the ONLY time it clipped, was on THX movies.

RMS ratings today are most definitely BS. Sure, you can get 1,000 watts from a system not much bigger than a cd player, but what they don't tell you is that's a signal tone pushed through a single speaker. The reality is that the system is really only putting out twenty watts per speaker in full range.
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