Bookshelf Speakers; Ported vs. Acoustic Suspension


I am building a new home and will have built-in bookshelves on one wall of a 15' x 12' room. I am planning on bookshelf speakers on either side of a 50" TV which has an opening of 60" W x 36" H x 24" D. I was thinking of purchasing ported design speakers (Silverline Minuet Supreme Plus) but was concerned about a ported design with only 15" of space between each speaker and the rear wall of the cabinet. Any experience here? Would I be better off with an Acoustic Suspension Design (NHT Classic 3)?
rjm0925
Since bass extension is already limited by the size, you might as well get the better transient response of sealed (acoustic suspension).
Its a valid question but difficult to answer. There are so many variables in question, just picking a pair of speakers on the basis of ported or sealed, probably won't do any good. One thing to keep in mind, though, is that the vast majority of bookshelf speakers were never intended to actually be put on a bookshelf. I think you definitely need to experiment in order to find out what will work.
Well I'm a "hands on" kinda guy, so I would opt for the ported setup and make some minor tweaks, if needed. The 15" space you described should be fine for any practical setup.

However, if you plan on concert levels, the ports may cause some minor issues. As long as the ports can breath around the other equipment, you'll be fine.

When building ported speakers, the rule of thumb, is to keep the port away from interior walls by at least the diameter/size of the port. For instance a 3" diameter port needs to be at least 3" from any interior wall.

While this isn't true of all setups (sub woofer systems can and do use different methods), bookshelf speakers should be practically unaffected as long as some space is dedicated to allow for the movement of air from any of the loudspeaker's output surfaces/area's. Come to think of it, a set using passive radiators may work even better for you.

That being said you can expect some over enforced bass lines, possible standing waves, and phase issues depending on your specific setup. But these should be minor unless you're really cramming everything together in one spot.

Although not applicable to your setup, the best sounding sub woofer setup I've ever heard is the Double Eagle system from Shahinian Acoustics. It uses four 8" drivers and four 10" passive radiators (two of each per L/R channels). Have you ever heard 5Hz at volume? Frightening enough, and even more so when you realize those are just a couple of 8's playing!

You probably already know this but the passive radiator design (when done correctly) eliminates the port noise that can be generated sometimes at volume. And do so without a loss of performance. In my case I've even achieved "better than ported" results when utilizing passive radiators. Their use is still somewhat of an art and requires a lot of forethought (experimenting) on the driver performance, cabinet design, and getting the radiators to match up with everything.

Sorry for the long answer, but I hoped I helped.
Andrew
Synesthesia Studios
...Or, since size is already limiting bass response, don't let a sealed box reduce it any further.
Zd,

Thanks for the response, I do plan to have a subwoofer to help with bass response. I am kind of stuck with putting the main speakers on a shelf on either side of the TV. I did correspond with Alan Yun of Silverline on this topic and he thought it would be fine and sent me a picture from his lab which showed the Minuet's on a bookshelf close to a rear wall.

I have always had freestanding speakers with plenty of room behind and to the side so I am in uncharted waters here. Trying not to make a fundamental mistake.
For the same size cabinet, Bass reflex has output to a lower frequency but its frequency response is less linear. In other words, bass reflex has a peak near its roll-off frequency and a dip above that. So, if you are going to have a suboofer, you will have an easier time combining with an acoustic suspension speaker, for flatter bass response. But, actually, mids and highs are so much more important to get right, that really the choice of speaker should really more depend on how its sounds to you, overall, with your room, your taste, and your equipment, so I don't think anyone can really advise you without your own personal audition and comparison. Taking anyone's advise about type, technology, brand, or even model make it a total gamble for your ultimate satisfaction.
USing the sub will definitely help address any concerns regarding low end extension.

Putting any speaker on a shelf close to the wall will pretty much always limit imaging and soundstage, if those are things you care about. Not much can be done about that.
In your situation, I went with sealed-cab speakers. They typically have a more gradual roll-off in the bass and hence are easier to integrate with a sub. I was worried about a "bass hump" because of close proximity to the front wall, but my bass is remarkable full, smooth, and well-integrated with a small sub. Very pleased. If you do go with ported speakers, you'd be better off with front ports, IMO, so they have room to breathe.
Inputs are greatly appreciated. Each speaker will be within 1" of the adjacent cabinet and TV. They will not be pushed back in the cabinet (i.e. front of speaker will be even with front of cabinet shelf). It would appear that sealed designs would be less risky but I really like the Silverline's.

Will need to give this some additional thought.
Adding a sub changes things. On the one hand, sealed box satellites might do some things better, but most subs don't work very well when asked to go much beyond the bottom octave, so ported satellites might work better in that regard. I suggest you consider and try both, and decide what you like best, regardless of whether or not the satellites are sealed or ported. Besides, there aren't that many that are designed to work so close to a wall to begin with.
Thanks all, seems like the best approach is finish the house and try both sealed and ported. It would appear that the sealed options would work better but I will experiment once I can.
Rjm0925..I already mentioned on another thread about the remarkable "CLUE" bookshelf speaker from Sjofn HiFi in Seattle. Its a ported speaker and the port is in the front and not the rear so you can put the speaker against the wall. For its size, it produces very powerful room filling bass typical of a large floor stander. Believe me, this little puppy will shake your room with outstanding bass performance since it plays all the way down to 28 hertz and rolls off much lower so its perfect for Home Theater as well. The speaker is 14" inches high, 8" wide, and 10.5" inches deep. Stereophile gives it a 10/10 rating.