Acoustics, speaker placement, subwoofers

Well that one is ported, you need at least need a bit of space behind it so it depends on how deep the shelves are. I reckon sealed is an easier to implement solution.

 

Completely agree with @Riotvan, a rear ported speaker in a bookshelf is generally a bad idea. But you could plug the port with a sock - that will of course cut off the low freq extension a fair bit, and sometimes change the character of the speaker a bit through the midbass and mids, but since it’s going to be situated in a bookshelf anyhow, I wouldn’t worry too much about that (since that location will change the character a fair bit anyhow).

 

In the family room I have PSB Imagine B on the bookshelf over the fireplace, driven by Van Alstine Ultravalve. Mind you, I use an active crossover at 80 Hz to SV Sound cylindrical sub located in the corner behind the Big Screen for WAF. Sounds pretty decent to me in most room locations. The building shakes when used in HT 2.1 mode and some LFE event occurs, such as the Night Fury in How to Train Your Dragon.

 

Yeah, I imagine doing some custom EQ can fix a lot of problem if they show up. I also seems that a speaker being surrounded by books can help reduce diffraction effects as well.

Suddenly got an idea for a high WAF large speaker. Bookshelves with a side firing "hidden" transmission line or BLH in the back with shelves in front. Or the opening can be at the very bottom or top.

Something like this but with shelves:

 

Is there a difference when it comes to setting up speakers meant to be enjoyed by several people at once? Not everyone can be in the sweet spot, so maybe there's an arrangement where the sweet spot drops a little bit in quality but everyone nearby goes way up.

Probably more common with home theater.

 

Generally you're looking for a certain type of directivity. It has to be controlled, so there are no surprises when going off-axis and it has to be wide enough to cover the listening position. HT speakers with horn loaded drivers are best at this.

 

Yup agree with @Hrodulf. Controlled directivity speakers with super aggressive toe-in (“cross the streams”). Check this out:

 

Hey all. I have a toe-in question.

In this scenario:

• You've already spent a lot of time positioning speakers in your room for the best possible bass response (minimizing room modes, nulls, etc.).
• In doing so, you found that the difference between an inch or two forward, backward, etc. seems to matter quite a bit in your room.
• You've done this positioning with the speakers firing straight ahead into the room.

You want to do some experimenting with toe-in. What is the correct pivot point for adjusting toe-in so you don't screw up the bass response you've achieved?

 

I have no personal experience with this because I always toe in from the start. My reasoning is as follows:

bass is omnidirectional it emits from the woofer, you do want to minimise the change in position of the woofer, chose the toe in method you achieves that in the best possible way, according to your sketches I would start with F. If your speakers have backfiring bass reflex than that method might not be best, but there is no way to toe in without changing either the position of the woofer or the position of the port if the port is backfiring.

 

I would try E center first. It wasn’t clear but did you measure?

 

My understanding is the acoustic center of a woofer is at the centre the cone where it meets the voice coil- so probably best to pivot around that. But if you have a port or passive radiator like @mitochondrium said, you’ve now got 2 pivot points, so you pretty much have to experiment again to sort it out.

 

Fixed a typo in the graphic. Thanks for the input. No @Riotvan I did not measure, just positioning by ear with music. In my case, I have Fortes with a 12" woofer in front and rear 15" passive, but I was also attempting to generalize to other speakers.

 

Well if you make a “backup” with painters tape on the floor or with a laser measure pointer or measure tape and a drawing you can just try it all imo. I have several pages with artisanal chicken scratch.

 

E. Center has seen some things...

Sorry, nothing to contribute, though I am still struggling with the same thing in my space.

edit: I mainly do movies from the couch and feel like I need to readjust my speakers depending on the mix.

 

Oh if you meant measure distance, then yes I have done it before. I thought you meant with a measurement mic and frequency sweeps.

 

You had it right, meant mic before and when you said you hadn't use it i switched to the alternative. Sometimes i leave out stuff when i put my thoughts into words.

 

A great resource for this kind of question is Jim Smith's book "Get Better Sound". He describes his process of getting a set of speakers to "play the room", a euphemism for proper placement to optimize the sound. It is a left-brain/right-brain process, with careful measurement of the position of the speaker(s) relative to room boundaries and the listening position followed by listening for changes to sound as a result of the new position. Small positional changes (as little as 1") can make differences. I personally found it incredibly helpful in locking in my preferred speaker positioning.

The book covers a wide range of "audiophile" topics, and can be an amusing read at times.