QuestionI have a Sony str-dg800 audio/video receiver, along with a Infinity IL-25c center channel (dual 5 1/2 inch speaker cones cmmd technology, etc...) two Primus 360 floor standing front speakers, 4 primus 250 floor standing speakers that are my Surround L, SR, SBL, SBR, and also two 150 watt subs. I have a 20X24 room which is enclosed perfectly for this type of speaker system. I also have a Super Audio Compact Disk Player/DVD upconversion 720P/1080i to watch movies in, and listen to Super Audio with my hybrid specially formatted disks. My question is: Why do places push for surround sound speakers to be small. Is it mainly for people that don't have space, or is there something I am missing out on by having floor standing speakers as surround sound speakers. I have actually tried speakers of alot more money (B & W, Paradign,etc) that have the small di-pole/bi-pole surround sound line, and doesn't seem to come close to what I have in true sound,(especially for music) please give me some expertise on your experience with different speaker combo's and tell me what you're thoughts are. I am not a professional by any means but I am above average in this field and will under stand the lingo, (decibels, receiver adjustments, different frequencies and what they pick up, etc....)so you can speak freely without wondering if you're being to technical. I dont know anyone to help me on this level so I am looking forward to hearing your opinion. Thank you for you're time
Timothy King
AnswerHi Tim,
Sorry I didn't get back to you earlier but that was allot of questions wrapped in one and I needed time to gather my thoughts and type this out. You may or may not realize that you’ve just asked the ultimate question, “Empirically, what’s best?”
The answer is frequently complicated by consumer economics (what sells, what makes profit), disparities between professional equipment/budgets/spaces and their residential counterparts, and a seeming disparity between scientific facts and enthusiast folklore. I’ll do my best to give you the facts as they are, I’m not so worried I’m going to lose you, but bear with me… this may be a long ride.
First let me cut to the chase: You’re not missing out on anything, speaker-wise. Given the volume of your room, I’m glad to know you’ve got the set-up you do. I’m not easily impressed, Great job.
Now, where were we?
Surround Speakers:
Why small?
Well, that a more subjective question about people’s taste – I don’t know that I can drop any hard science on that one.
I could cite an industry bell-curve index that tells us that the large majority of consumers in the middle are only willing to spend X amount for a stereo system. The trend shifted up about 30% when surround came into the picture, but to upgrade from stereo to 5.1 was a 300% increase in audio channels. If you average that out you begin to see what happens – a sinking tide lowers all ships.
Also, the original standard consumer 5.1 format (even for THX) required only a LIMITED frequency response from the rear channels (that standard still exists, dolby has the charts online if you care to do more research). This was partly to save bandwidth on broadcast/digital media, but also to resolve the issue of localization (being able to pick out EXACTLY where the rear channel is coming from) that producers were concerned would distract from the media’s content. Conveniently enough, you don’t need a very good speaker to do that with a passing grade.
Then there’s the aesthetics. When you serve on a product design team, one of the major things that is discussed with the industrial designers is, “can you get to keep it?” In other-words, if someone (say a spouse, not to fall into stereotypes) makes an impulse purchase and takes it home to the family, will the other members tolerate it in their home environment, or will it get sent back? Small = more easily ignored, aesthetically.
This is further complicated by the massive “Brand index” of BOSE. No matter which side of the Bose fence you sit, its pretty much agreed that they became a marketing juggernaut in the ‘80s and ever hence, and there massive pillar in the public eye probably also lent some legitimacy to the “smaller” speaker trend.
There is one hi-fi argument in “smaller”s favor: Small drivers have very low directivity. If you ever look at some “Q” charts or polar-plots for different sized drivers, you’ll note that the larger a driver is the more “directive” it is. The science behind this is fairly elemental – at some upper frequency a driver is the same size as the wavelength its trying to reproduce – at that frequency and any frequencies above that it acts more like a piston than an omnidirectional point-source. The larger the driver the lower in frequency this phenomenon occurs - and so the speaker has a narrower polar plot before it crosses over to the tweeter. With a small enough driver, say a 4”, you get a very dispersed polar plot (sound is more even off-axis) - perfect for enlarging the “sweet-spot” in a crowded 10’x15’ rec-room.
The bi-pole/di-pole speaker needs to be handled with care.
When I develop computer models and run the with and without di/bi-poles, it seems like a good idea only for low-volume, close proximity conditions (small room, speaker within a meter of listener, not enough room to place it 30-45 degrees behind the ears). My understanding was that this was the original intent: In rooms where the Dolby theater standard for surround placement and room acoustics could not be followed you could draw these level with the ear and still limit your brain’s ability to detect the origin of the sound. (Well, at least as a single point source right by your ear).
EVEN THEN I’d prefer them over a traditional loudspeaker only about a third of the time. Di-poles/Bi-poles are heavily reliant on room acoustics – all it takes is one asymmetrical wall or window and you’ve got unwanted reflections.
If you think about where your media – movies, SACD’s, etc, - think about what they created on and for whom they were originally intended. In particular, modern 7.1 formats do permit full-bandwidth audio for all channels this side of the “.” (“Subs” get sub – not rocket science). This is particularly true for the commercial theater industry (but to be honest, digital Surround EX is more like 6.1). That’s why soundstages and final/mix-down studios do EXACTLY what you have done – full bandwidth STUDIO monitors on all channels. I’ve designed my fair share of theaters and studios, I’ve NEVER used a di/bi-pole.
True, DVD’s have already reached the limits of data bandwidth, and as such most engineers will apply an enormous amount of compression and EQ on the rears – but that’s mostly to avoid headroom limitations on the disc and to meet consumer expectations (again with the sinking tide). By having full-bandwidth on all channels you’ve made sure you’re getting the most you can. And you CAN because you are fortunate to have the floor-space to do the right thing.
If you look at a good commercial theater, usually all the speakers are direct (none of this “Bi-pole/di-pole contrivance for us). In fact, manufacturers frequently use manifolds on high-frequency compression drivers to make a tweeter that is also as directive as the woofer (well, not entirely – power handling and some other factors play into it). All channels are (more or less) full-bandwidth – at the very least they’re better than what most consumers get for surrounds. This is the format the original production team (the producers, the director, the engineers) works their vision into. Your system is as close of a reproduction of that environment as one can hope for.
As far as speaker placement, go to the source… Dolby has some pretty good “white papers” hidden amongst their consumer and pro sites. If you can find it, download the recording engineer manual and follow/replicate the guidelines they give for studio encoding/playback set-ups. That way you’ll be even closer to hearing what “they” heard when “they” put it together.
So what else might you be missing? Well…
There's one great big factor that almost every consumer overlooks that could make an even bigger difference than buying new or expensive speakers:
ROOM ACOUSTICS.
Audio systems do the same thing as lighting - they convert electricity into energy in the room. I tell architects all the time - no amount of expensive lighting can improve the aesthetics of a room if you've painted it neon green-and-orange paisley.
Similarly, no speaker or decoder is going to sound its best in an all tile or plaster square room. Consider applying acoustic absorption and diffusion elements to your room, and make it acoustically as symmetric about the center channel as possible. In all my experience I have found that room treatment is where your money can go farthest. Here are some resources I recommend:
Diffusion:
http://www.rpginc.com/research/research_topics.htm
http://www.allnoisecontrol.com/products/DiffusionSystem.cfm
General Acoustics:
http://www.ecoustics.com/Home/Accessories/Acoustic_Room_Treatments/Acoustic_Room...
http://arts.ucsc.edu/EMS/Music/tech_background/TE-14/teces_14.html
http://en.wikibooks.org/wiki/Acoustics/Fundamentals_of_Room_Acoustics
http://www.crutchfieldadvisor.com/S-6fH4dvTTtdr/learningcenter/home/speakers_roo...
There are lots of cheap and attractive ways to alter the acoustic properties of your room - book shelves with books of random size make great diffusors and traps – quilts, thick pile carpets, and polar fleece curtains make for great absorption.
And for finer points:
CONTROL SYSTEMS
If you did all this yourself and are left with a coffee table full of remotes (or are limping by with an all-in-one like a Pronto) you might want to consider an integrated control system, such as something from Crestron or AMX. These usually involve pretty pricey touchscreens, and a significant portion of the cost is associated with hiring a professional to program it.
Xantech is a little less full-board but more DIY friendly. There are also other players out there, like Extron’s IP Link and Aurora’s WACI, that would permit you to build up HTML web pages yourself and use a laptop or tablet PC as a control center.
If you want to know more about any of these topics, send me another query and check the box marked “private” – then you can feel free to leave an email for an offline conversation.
