Baffle Step Compensation and AVR Software

[konajoe]

Will any of the room correction packages currently available with AVRs effectively do baffle step compensation?

 

[fuzz092888]

Why do you want it to do baffle step? If you've purchased pre-made speakers, generally speaking, that's already been taken care of in the crossover design.

 

[Swerd]

Will any of the room correction packages currently available with AVRs effectively do baffle step compensation?

To my knowledge, no room correction packages directly address that problem. However, there may be some that might indirectly effect baffle step compensation to an extent that it might improve things. It depends on the speakers you have and their location in the room.

Do you want to add or subtract BFC to your speakers?

 

[konajoe]

I used this as my reference to understand BSC: http://www.salksound.com/wp/?p=42

Sometimes, I run across speakers that the manufacturer claims can be wall mounted or placed on a stand. According to this reference, they'll sound different in each location. That's fine if you have the flexibility to move them between on wall and stands. Just put them where you want them. But what do you do if you have rigid placement requirements? The speakers don't have BSC on them. They can't be designed for BOTH placements if they don't have BSC compensation. So, will software such as Audessey effectively make the corrections?

 

[fuzz092888]

What would be more pertinent is giving more information on your situation. Do you have rigid placement requirements? What speakers are you looking at, or are you even in the market? Some speakers are perfectly happy up against a wall and some must have that extra space either behind or to the side in order to sound their best. If you're buying from an online vendor, odds are they'll be able to tell you what placement their speaker was designed for. If your'e buying local, then go there (to the store) and ask to demo the speakers and ask if you can move them into the positioning you want (ie as similar a position as you can to your rigid placement at home).

I guess to answer your question, buy the speakers that are already designed to work in the situation you have. Don't rely on room correction to figure things out. Audyssey and other room correction can help out a lot in terms of FR response, nulls, peaks, and other wonky effects a room may have, but not much save room treatments will help more than proper placement or buying speakers that will work in whatever placement you're going to use them in.

To use Salk as an example, they have several different models including the Songtower. Now the Songtower can be built with a front firing or a rear firing port. If you e-mailed Jim and explained whatever your placement restrictions he would be able to recommend the right speaker and port for you. Much like he offers some open back midrange speakers. Now if you're only placement options were crammed against the wall, he would steer you away from those speakers in favor of a sealed design or something of that nature.

To summarize, room correction can and will help a little, but is no substitute for matching the right speakers to your space/placement restrictions.

 

[konajoe]

Here's one of many that I've seen: http://www.bowers-wilkins.com/Speakers/Home_Audio/600_Series/686.html

They talk about it sounding good on a wall, bookshelf, or anywhere. They show a picture of it on a stand. I'm guessing it was designed to be wall mounted, and that the baffle effect would make the bass weak if it were moved away from the wall. Probably just an overblown statement on their part, unless the correction software does a good job.

 

[fuzz092888]

Here's one of many that I've seen: http://www.bowers-wilkins.com/Speakers/Home_Audio/600_Series/686.html

They talk about it sounding good on a wall, bookshelf, or anywhere. They show a picture of it on a stand. I'm guessing it was designed to be wall mounted, and that the baffle effect would make the bass weak if it were moved away from the wall. Probably just an overblown statement on their part, unless the correction software does a good job.

That does look like it was designed to be mounted on wall with the front firing port. Odds are you are also correct that the bass and possibly midrange will weaken as it is moved out into the room as well.

 

[Swerd]

I strongly suspect that no AVR can correct or modify speaker crossover networks enough to qualify as BSC.

Your Salk link for explaining BSC is a good one. Many commercially available speakers lack BSC, and actually require placement close to walls. Many others have it built-in to the crossover. Salk and Philharmonic Audio speakers definitely have roughly 4 dB of BSC built-in to the design and are designed to be placed away from walls. BSC has nothing to do with speaker ports, and the baffle step problem exists with any speaker in a cabinet whether its sealed or ported. Some speakers come with a switch that allows adding or removing levels of compensation that would allow you the option of placement closer to a wall.

Ask Jim Salk or Dennis Murphy about this, and ask them to build you a speaker that you can mount where you need to put it. If you have to wall mount it, they can take out the BSC from the crossover network.

That B&W 686 link says:

An ideal bookshelf or wall-mounted speaker, the 686 S2 is designed to fit into any space and still sound perfect. Its main driver is a 5-inch bass/midrange unit which benefits from a new 25mm voice coil which makes for a higher sensitivity speaker with bass more suited for placement near a wall.

This sounds too good to be true.

Bass performance is vital but can often suffer in smaller speakers. Not in the 686 S2, however. That's because a front-firing Flowport, dimpled like a golf ball around the aperture for smoothly regulated airflow, delivers superior bass response without the risk of rattle. Its placement ensures the speaker cabinet is slimmer than predecessors and can be wall mounted without affecting performance.

This has nothing to do with the presence or absence of BSC. I don't think B&W would answer you if you asked them how much BSC did they design into the crossover network?

 

[Dennis Murphy]

One thing to keep in mind is that there's wall placement, and then there's wall placement. If you place a speaker on a wall mount so that it's sticking out a little more from the wall than the depth of its cabinet, you will still need almost as much BSC as if the speaker were on stands a foot or two from the wall. (This ignores any adverse results from a rear-firing port placed too close to the rear wall.) I've listened to and measured speakers that were right up against a rear wall and speakers that were stand-mounted away from the wall, and there's not much difference. I remember when someone brought over an Internet-Direct speaker that he had on trial to get my take on why he didn't like it. I listened a minute or two, and heard the obvious signature of inadequate BSC. Just to see whether it would help, we backed the speaker flat up to a wall. Virtually no difference. The baffle step is only seriously attenuated when the speaker is mounted in the wall, so that the front baffle is flush with the wall and forms an infinite baffle. BSC is a critical part of any crossover network for the vast majority of speakers. Will room correction software rescue a speaker with inadequate BSC? It might help, but there's more to good sound than post-hoc equalization. There are phase relationships to take into account, and the best solution is always to design a crossover that gets the fundamentals correct in the first instance.

 

[TLS Guy]

One thing to keep in mind is that there's wall placement, and then there's wall placement. If you place a speaker on a wall mount so that it's sticking out a little more from the wall than the depth of its cabinet, you will still need almost as much BSC as if the speaker were on stands a foot or two from the wall. (This ignores any adverse results from a rear-firing port placed too close to the rear wall.) I've listened to and measured speakers that were right up against a rear wall and speakers that were stand-mounted away from the wall, and there's not much difference. I remember when someone brought over an Internet-Direct speaker that he had on trial to get my take on why he didn't like it. I listened a minute or two, and heard the obvious signature of inadequate BSC. Just to see whether it would help, we backed the speaker flat up to a wall. Virtually no difference. The baffle step is only seriously attenuated when the speaker is mounted in the wall, so that the front baffle is flush with the wall and forms an infinite baffle. BSC is a critical part of any crossover network for the vast majority of speakers. Will room correction software rescue a speaker with inadequate BSC? It might help, but there's more to good sound than post-hoc equalization. There are phase relationships to take into account, and the best solution is always to design a crossover that gets the fundamentals correct in the first instance.

That is exactly my experience, if it sticks out from the wall the speaker needs BSC.

 

[konajoe]

So, take a look at this cabinet, for instance: http://www.amazon.com/Parker-Furniture-Huntington-Entertainment-Bookcase/dp/B00GS87DWQ/ref=sr_1_73?s=furniture&ie=UTF8&qid=1417494649&sr=1-73&keywords=entertainment+center

Let's say that the left and right speakers will be placed at ear level (seated position). In this cabinet, the speakers could be placed in that outer rounded cutout or the inboard enclosed cutout. At the inboard position, a speaker would act more like an in-wall speaker from what I'm understanding. In that outboard, half-enclosed space, the speaker would act like it was an in-wall speaker on one side, and like it is on a stand on the other side. Correct? Weird.

 

[fuzz092888]

Is this all just conjecture or are you looking for a solution to a specific problem?

 

[konajoe]

Well, knowledge is power. I'm looking at a WAF situation here. I'm also looking at the reality that I may not be able to audition speakers in our house. I'm also looking at the reality of an in-store audition probably won't translate well to how they'll sound at home.

So, the easy answer would be that such-and-such room correction software would be able to take care of problems caused by putting speakers in a home entertainment center. I'm hearing 'don't count on it'.

I'll have part of the choice in a home entertainment center. So the question I still have is whether speakers placed in those 2 bookshelf positions will act more like in-wall speakers or speakers moved a little away from the back wall. That will help me chose and demo speakers.

 

[Swerd]

So, the easy answer would be that such-and-such room correction software would be able to take care of problems caused by putting speakers in a home entertainment center. I'm hearing 'don't count on it'.

So the question I still have is whether speakers placed in those 2 bookshelf positions will act more like in-wall speakers or speakers moved a little away from the back wall. That will help me chose and demo speakers.

I think 'don't count on it' is the best answer.

Most people who understand what BSC is, are concerned whether a speaker has enough of it designed into the crossover. You ask if a speaker with adequate BSC will sound like it has too much bass if its placed in a bookshelf cabinet. Based on what Dennis Murphy said, I'd be willing to guess that you wont need to correct anything under those conditions.

Dennis Murphy taught me what lack of BSC sounds like, and what it looks like on a speaker frequency response curve. His answer, repeated below, says it best:

If you place a speaker on a wall mount so that it's sticking out a little more from the wall than the depth of its cabinet, you will still need almost as much BSC as if the speaker were on stands a foot or two from the wall. (This ignores any adverse results from a rear-firing port placed too close to the rear wall.) I've listened to and measured speakers that were right up against a rear wall and speakers that were stand-mounted away from the wall, and there's not much difference.

The baffle step is only seriously attenuated when the speaker is mounted in the wall, so that the front baffle is flush with the wall and forms an infinite baffle. BSC is a critical part of any crossover network for the vast majority of speakers.

Will room correction software rescue a speaker with inadequate BSC? It might help, but there's more to good sound than post-hoc equalization. There are phase relationships to take into account, and the best solution is always to design a crossover that gets the fundamentals correct in the first instance.

 

[bang4bucker]

Well, knowledge is power. I'm looking at a WAF situation here. I'm also looking at the reality that I may not be able to audition speakers in our house. I'm also looking at the reality of an in-store audition probably won't translate well to how they'll sound at home.

So, the easy answer would be that such-and-such room correction software would be able to take care of problems caused by putting speakers in a home entertainment center. I'm hearing 'don't count on it'.

I'll have part of the choice in a home entertainment center. So the question I still have is whether speakers placed in those 2 bookshelf positions will act more like in-wall speakers or speakers moved a little away from the back wall. That will help me chose and demo speakers.

to understand baffle step compensation you need to understand baffle step loss first. any driver mounted on a baffle will have reduced lower frequencies. to calculate -3 db point they use this formula : F3 = 11,600/baffle width in centimetre. so, a driver mounted on a baffle of 20 cm with will be down 3 dB at 11,600/20 = 580 Hz. the loss is actually 6 db. that's baffle step loss. driver's sensitivity will be reduced to compensate that. and that's baffle step compensation.

so, to answer your question whether speakers placed in those 2 bookshelf positions will act more like in-wall speakers or speakers moved a little away from the back wall the answer is NO. what you are talking here is room gain, not BSC.