Rear Ported versus Non Rear Ported floor standing


I have a space limitation in our room which means that the speakers can only be placed a max of 6-8" from the rear wall. Does this mean that I need to stay away from rear ported speakers because they all have diminished sound because of the base or will all speakers have the same result . Any recommendations would be appreciated. Have heard at audio shop SF grand piano all off the rear wall, Spendors (rear ported) & Focal Chorus ( not rear ported).
murr
>>If a speaker goes too low for a room to contain the bass the speaker can produce you are in for standing room city, which is worse than a little extra bass bloat by putting a rear ported speaker in a cabinet!<<

This is a huge assumption and mostly hifi wives tale. Standing waves in the bass regions are mostly a function of diaphramic losses and in reality no playback room is big enough to properly handle the bottom octave.

In a very truncated nutshell, you can have great bass behavior, even down to 16Hz in a small room. Standing waves will likely be more of an issue in small rooms with bass in the 50Hz to 80 Hz range.

I recommend you bone up on this a little. There are a couple references that will help you understand better:

One is "Fundamentals of Acoustics", Third of Fourth Edition
Wiley press

The other is Harry F. Olson's book. It contains less math, fewer proofs and is totally solid; easier to understand if you do not have a strong math and physics background.
Does anybody have suggestions for front ported or non ported floor standing speakers for a L shaped room 11x14 & 10x10. thx for the suggestions
Of the three you listened to - what did you like best? What other speakers have you owned that you like? How important are aesthetics? Do you have an amp already or what will you use to drive them? There are a great many good speakers out there - each with strengths and weaknesses.
Whether or not a speaker works well near the wall depends on the details of the design. While as a general rule of thumb we could say that the average rear-ported speaker would not work well in such situations, there are exceptions that work exceptionally well.

For instance, Audio Note uses rear-porting on speakers specifically designed to go in or near a corner. They use a lower-than-normal tuning frequency. I can think of four reasons why their approach is a good idea.

First, by tuning the port lower than normal the bass boost from corner loading results in deeper bass extension instead of boomy bass.

Second, it is not terribly difficult to shape the low-end response of a reflex enclosure so that it's approximately the inverse of the low-frequency gain from boundary reinforcement. The shape of the low-end response of a sealed box speaker has a much more limited range of adjustment, and the only way to get a reasonably close approximation of the inverse of boundary reinforcement is to use equalization.

Third, lower tuning frequencies call for longer port lengths, and longer ports are more likely to emit some midrange coloration (at a reduced level of course due to damping material inside the box). By directing this undesirable midrange energy away from the listening area, it is less likely to be audible (and in most cases is inaudible).

Fourth, by staggering the distances from the low frequency sources (woofers and ports) to room boundaries in all three planes, the bass is likely to be a bit smoother at the listening position.

I like Audio Note's approach enough that I use a variation thereof in some of my own designs.

In my opinion rear ported speakers specifically designed for (or adaptable to) placement close to the wall can work very well there.

Just for the record, I'm not really an advocate of vented boxes as inherently superior to sealed boxes in the bass region. I do like the greater design flexibility of the vented box, but overall it's a trade-off of one set of compromises versus another. All else being equal, vented box woofers have more powerful magnets than comparable sealed box woofers, and this usually translates into better midrange performance.

Duke