Front ported or sealed box.
Also check here:
http://www.northacoustics.com/ |
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>There seems to be a lot of bookshelf sized speakers which all seem to provide far better performance as a stand mount
>What mid -high end speakers provide the imaging openess etc on a bookshelf ?
None, the problem being that even mid range wavelengths are acoustically large compared to the baffle dimensions so they go around the speaker, bounce off the wall, and arrive at your ears soon enough to be confused with the direct sound.
There are exactly two reasonable speaker placements:
1. A reasonable distance from the wall behind them. The greater of 4' and half the distance to the listener is probably a good start pushing the reflections off the front wall out 7ms and making them 6dB down from the direct sound. 3' isn't as good, 5' is better.
2. In the surface. There's no separate reflection from the direct sound to confuse with it. There's no diffraction offf the speaker baffle. In-wall speakers have the potential for superior sound in all areas except sound stage depth which seems to require some reflections to come from behind the speakers.
A wider speaker which tapers towards the wall built for on-wall placement would fit category #2.
If you're stuck with the placement, speakers not designed to go there are going to give your singers chest colds when the reflections add in-phase to the direct sound.
Your best bet is to pick speakers designed for the placement. This isn't necessarily a bad thing because you can pickup 3-5dB more efficiency, output at a given distortion level, and head room. Jim Salk (salksound.com) sells his HTS MTM and MT configurations with cross-over options for on-wall and in-wall use. Revel has some speakers with a boundary comepsnation switches. It's rare.
Next best would be to deal with the problem using electronics. A shelving high-pass filter as found on pro-sound parametric equalizers will do the trick. Home theater preamps are starting to incorporate "Audyssey" which is self-calibrating using a microphone. One Audiophile room correction solution would be the TacT RCS system. It would be better to use appropriate speakers though, because ones built for stand mounted use are throwing away amplifier output so they can pad the higher frequencies down to match the lower ones with wave lengths long enough to wrap around the baffles.
As long as you have enough clearance to avoid aerodynamic problems, moving the port from the back to the front or eliminating it isn't going to do a anything for you. |
>Or is it a matter of compromise or increasing the WAF by having speakers on a stand imposing in the room?
If you're looking for WAF, Triad sells in-wall versions of most of their speakers. Everything they do is made to order and they can provide grills that match your decor/wall color. |
Wilson Duet speaker is a true bookshelf speaker. |
I have an ad running now for Soliloquy Sat-5's. No ports and really solid, heavy boxes make them great for bookshelves. If you ever decide to put them on stands, they image nicely and look great too. |
You need sonic hollography.
Find a good tube amp and invest in top notch 5751s as inputs and 6SN7 Jan CHS 6SN7W metal base tubes. The speaker will try to sound flat but the amp will break their will with magnificant tubes. You can get real chrome domes if the aforementioned Ws are out of reach. You can buy OEM labled Chrome domes they are close but not as good as the "W" s etc, but are a true chrome dome 6SN7GT which 'out images' the rest.
The other option is to tell your sweetest that she won't die if good speakers are present. Some of the people she wants to impress may well find themselves admiring them.
I picked 4 1940s yes 40s 6SN7gts for $5 a pop labeled motorola etc. two matching pairs. I also snarfed 1948 GTs with a world record of chrome flashing both Sylvania marked 1948 for 21 bucks a pair.
5751s you have to get by chance from a friend or dependable dealer. I have a number but not a ton for spares, good ones asre precious. Try your luck on ebay although they are too much money some are fairly priced OK variants that give you the idea. The JAN tubes circa 1975 from Sylvania not the most halographic tube that some of the vaunted tubes are. I know I have both.
On a different stroke the 50s 60s and 70s Heerlen 7136s a 12au7 from Amperex only for special apps are expensive but about as good as a small input tube that exists, never mind the label HP. Beckman etc ordered them for there durability and liniear behavior. They work in audio like nothing else. Your speakers will come to life with decent output tubes not the cheapest you can find.
There is acompany that was selling the ultimate monitor a year or two aga If they exist and oprices are normal not stupid sill then they sounded like a choice.
I have two powered pairs I never use. One is tubed. |
>You need sonic hollography.Find a good tube amp
That's the opposite of what you want to be doing. A speaker with baffle step compensation for placement away from room boundaries is going to have 3-6dB more output at its woofer and port resonances when stuffed into a book shelf.
A tube amp with non-negligible output impedance (especially a single ended triode) is only going to make it worse since it boosts output at the speaker resonances.
>The other option is to tell your sweetest that she won't die if good speakers are present. Some of the people she wants to impress may well find themselves admiring them.
Or you can get your sweetest to park her cute little butt in your favorite chair in front of a reasonable setup where she's pleasantly surprised at how into the music she can get without having had anything to drink.
Apart from the spousal issues this is basic physics and arithmetic. Wave lengths larger than the speaker dimensions are going to wrap around it and bounce off the front wall. Since they're large compared to that distance the phase shift will be minimal, with the distance small compared to the listening distance the reflections will arrive at approximately the same amplitude, and you'll have nearly 6dB of boost at lower frequencies.
Fourfold increases in your bass, mid-bass, and lower mid-range output power work well to sell bad speakers to the unwashed masses but aren't hi-fi.
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I have a large wall-sized custom made bookshelf along one wall of my library/sitting room. Stand mounted speakers and floorstanding speakers were out of the question. Of course placing speakers into a bookshelf is a compromise, but it is possible with the right speakers. I have a pair of Von Schweikert VR-1s that sit perfectly into the bookshelf and are surrounded on all sides with books. This makes them flush and essentially "in-wall". I have pulled them out onto stands on occasion and they sound better, but I am quite content with them in the bookshelf. I know it is heresy, but worth a try. If you can find the right sounding speaker with the right dimensions, it may work for you. Since this is not my only system I can compromise. If this is your only system, you deserve the best sound you can get, or use headphones, which I also do in my library. Good luck! |
There is a reason why most "bookshelf" speakers sound better when stand mounted. It usually has little to do with the stands themselves, but with allowing some space around the speaker (sides if not rear) and also for proper height positioning.
Think about it - what speakers would you imagine sounding good when placed inside a tiny cave (and you are outside the cave)? Reflections resonance (from the loosely mounted shelf) and proximity damping are the main problems working against you here. Almost any speaker placed on a standard height and width bookshelf space is going to sound, more or less, like a dorm room (no offense to those of you who might have great systems in your dorm room).
So, what can you do? You can try the following:
1- If you must use a bookshelf speaker on a bookshelf, try a horn loaded model like the Klipsch RB series or the HSU HB-1. Some folks have reported great results with Linn Tukans on a bookshelf, but I have only heard them on stands.
2- If you can lose a couple of shelves, try mounting a speaker designed for on-wall centered in the empty space. I have a pair of Dynaudio Audience 42W that are stand monuted in my office, but might work as this way.
3- Forget the bookshelf idea and use a relatively small floor or stand mount speaker. Again, a horn loaded speaker would work well, but I might try a Snell-style speaker like those offered by Audio Note.
Have fun. |
I have my VR1s set up exactly as Tgrisham notes above, and it sounds great. On the built in bookshelves, surrounded by books. This is on the long wall of a rectangular living room. I sit on the sofa directly across from the speakers which are positioned just slightly higher than ear high. The design of these spkrs allows a pretty wide seating area and sweet spot. My wife was really happy for me to get my old floorstanders out of the living room, and for the room size, these speakers sound great. Of course, now I am moving and will have my own media room/home office where I can set up my huge Dynaudio floorstanders and really rock out. The VR1s will go into a bedroom setup. They really produce lovely bass down to around 50 hz or so. They have a small rear port that can be placed close to the rear wall. Sure, they get a little boomy in the upper mids in this setup, but they still sound nice. PS: I used blue-tack to stick the speakers to the bookshelves, which really helped with imaging and tamed any vibrations on the shelving. |
