# From the expert?



## tcarcio (Jun 27, 2007)

OK, so I am cruising the net checking things out and I run into this posted blog from the so called ''expert'' on bass. Now I admit that what this guy knows about bass dwarfs my knowledge but it seemed to me that the same things that I have read about bass and actually implement in my HT are completly wrong. I thought you guy's here would be interested in his opinions and I for one would be very interested in what you think about his. link to the article....http://theprofessionalanswer.com/?p=239#more-239

his conclusion;

What do you need.

1) All subs in the front of the room only. This keeps the entire sound image cohesive as it passes from the front of the room to the rear insuring a broad, natural and balanced soundstage.

2) Two matching, high-performance subwoofers, one located next to the front-left main speaker and one located next to the front-right main speaker. Both subwoofers must posses identical high-performance characteristics to insure proper phase behavior, smooth frequency response and tight percussive/transient characteristics.

What you need to avoid.

1) Single subwoofer system designs. This results in disconnected low frequencies, sonic and visceral hot spots, dead spots throughout the room, a smaller listening area and dynamic limitations.

2) A pair of non-matching subwoofers (different brands, models, vintages etc). This results in muddy, inconsistent and conflicting bass information due to the different manner in which each sub will reproduce a given frequency.

3) Deep corner placement of subs. Although in some cases this may be unavoidable, placing your sub(s) deep in the corner will tend to cause peaky/boomy frequency response when compared to placement slightly inward and/or forward of that location. Ideally, each subwoofer should be located as close to it’s corresponding main speaker as physically possible. A Room Optimization feature such as the JL Audio ARO can effectively compensate when conditions leave no alternative to corner placement.

4) Center wall placement. Placing subwoofers in the mid-wall or center location will create the most room cancellation and negatively impact low frequency performance. This cannot be corrected with the use of optimization features or EQ and should be avoided whenever possible.

5) Running main speakers in “Large” or “Full-Range” mode. This will cause a conflict between the manner in which your main speakers reproduce low frequencies and that of your subwoofers. It will also cost you the advantage of lower distortion from your main speakers by relieving them of distortion-causing bass duties.

6) Subwoofers located throughout the room. Placing subwoofers anywhere except along the front plane of your listening room will create multiple time coefficients and numerous problems with regard to sonic performance. In a best-case scenario, this only allows for the optimization of one seating position. This is a common mistake among those utilizing multiple subwoofers.

This industry suffers no shortage of “experts” or opinions when it comes to subwoofers and their implementation. I have become one of those “experts” that people look to for such advise however, in my defense, I have more “seat time” and success with subwoofers than most. It is not very often that I speak in terms of absolutes however, on this particular topic, I am quite comfortable advising this approach to subwoofer implementation for all applications. I wish you all the best and, when all is said and done, “Turn It UP, and ENJOY!”


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## tonyvdb (Sep 5, 2007)

I disagree with his statement that "_All subs in the front of the room only. This keeps the entire sound image cohesive as it passes from the front of the room to the rear insuring a broad, natural and balanced sound stage_" although it can work better this way many people have very good results by placing them in different parts of the room.

I also disagree that you must have two high performance subs as most of us simply can not afford to do it, its that simple. One is better than no sub.

"_Subwoofers located throughout the room. Placing subwoofers anywhere except along the front plane of your listening room will create multiple time coefficients and numerous problems with regard to sonic performance. In a best-case scenario, this only allows for the optimization of one seating position. This is a common mistake among those utilizing multiple subwoofers._" He needs to talk to Sonnie I bet he could change his mind.

This makes me laugh, "_This industry suffers no shortage of “experts” or opinions when it comes to subwoofers and their implementation. I have become one of those “experts” that people look to for such advise however, in my defense, I have more “seat time” and success with subwoofers than most._:dumbcrazy:


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## tcarcio (Jun 27, 2007)

I also disagreed with his saying not to put subs mid wall. After a ton of experimenting I got the flatest response I could with my 2 subs stacked at the mid wall to the left of the seating position. That ''expert'' comment was good for a chuckle........:heehee:


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## Maceo23 (Mar 16, 2007)

It seems that this guy has done his homework and has found that these rules work best for him. The thing that bothers me about his theory is that he is almost trying to argue that subwoofer frequencies are directional. Listen, If I was building a 2 channel rig with subs, I would definately try to have the stereo subs as close to the mains as possible. I would probably have them placed in the corners next to my mains, per Richard Vandersteen's recommendation ( I have 2ce sigs) than an "expert" on the interweb. For HT, the bottom line is do what sounds best to you. I really don't like my subs near field, but thats just taste. If I had it my way, I would have a dedicated sub for each speaker in my system, but I ain't got that kind of scratch.


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## Sonnie (Apr 11, 2006)

*bologna!*


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## tcarcio (Jun 27, 2007)

C'mon Sonnie don't hold back, Tell us how you really feel....


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## Wayne A. Pflughaupt (Apr 13, 2006)

_“... a left/right pair of subwoofers (near your main speakers) will always yield the best results.

2) Two matching, high-performance subwoofers, one located next to the_ front-left_ main speaker and one located next to the_ front-right _main speaker._

That was my thinking when I got my first subs by dropping a pair of 12” Shivas into some old ’70s tower speakers I had taking up space in the closet. I figured that putting them up with the main speakers was the thing to do. You can see them here in this period photo of my system – that’s them to the outside of the main speakers, the tall black things (the smaller speakers on top of them are front speakers to maximize Yamaha’s DSP modes).







​

Take a close look at this picture. Notice that to the right of the left main speaker there is a big “hole in the wall,” a little hallway that opens to a couple of bedrooms. To the left of the left speaker / sub, between the brick fireplace (barely visible here, bottom left) and the wall, was another hallway that went to the front door.

So – one sub in a corner, the other on a flat wall with all these openings. How well do you think it worked? :rofl:

The right one naturally had a lot of output and extension. The left one, when I tried to EQ the extension needed to match the right, it would bottom out during movies. :gah:

Here’s the kicker: When I finally located both subs to the corner, I saw at least a 6 dB improvement in SPL. Which means that when the one sub was to the left on that “perforated” wall, _it contributed absolutely nothing to increased dB levels!!_ Talk about a waste. After EQ there was better extension overall, and no more bottoming out! :yay2:

_3) Deep corner placement of subs. Although in some cases this may be unavoidable, placing your sub(s) deep in the corner will tend to cause peaky/boomy frequency response when compared to placement slightly inward and/or forward of that location._

That’s generally correct, but I measured a big ol’ honkin’ _null_ at a good buddy’s house with his sub in the corner!! 



tonyvdb said:


> I disagree with his statement that "_All subs in the front of the room only. This keeps the entire sound image cohesive as it passes from the front of the room to the rear insuring a broad, natural and balanced sound stage_" although it can work better this way many people have very good results by placing them in different parts of the room.


In my son’s room, I measured the best response _by far_ in the corner behind the seating. I prefer my subs to be up front too, but I’ll take “best performance” over a “time-coherent wavefront” any day. :T



tcarcio said:


> I also disagreed with his saying not to put subs mid wall. After a ton of experimenting I got the flatest response I could with my 2 subs stacked at the mid wall to the left of the seating position. That ''expert'' comment was good for a chuckle........:heehee:


 Funny, I got the absolute _worse _response at that location... :huh:

All of which only goes to show what I’ve always said: Take articles like this with a grain of salt, because they’re only valid in the room where the experimentation was performed. Every room is different; you need to experiment take readings to find what works best in yours!!!

Regards,
Wayne


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## thewire (Jun 28, 2007)

Sounds like someone not familiar with high-end systems. None the less it's an interesting read to see their viewpoint and like many they have come to conclusions based on their own experiences/knowledge. To really observe/test and conclusively evaluate subwoofers in a room one needs to approach the matter like an experiment as done in the Harmon papers. Some mathematical simulations might be fair for such statements in a perspective of what theoretically will work. One simply doesn't make such claims as an "expert" without the data to back it up.


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## brandonnash (Sep 11, 2006)

Sonnie said:


> *bologna!*


and not even good bbq bologna. just regular store bought ghetto round steak bologna. I'm with everyone else in this one. While I do believe front placement is good for blending bass with the mains, with a low enough crossover, exact channel leveling, and proper phase adjustment the sub will perfectly blend with the rest of the speakers. I didn't start believing this till I heard a demo in a sound room at a car audio shop. The subwoofer was setup just as I described and you couldn't tell where it was in the room. It was directly behind the listening position. It's not absolutely necessary to put the subs up front. If you can, great. Try it and see if you like it. If you can't place there just make sure it's set up correctly.


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