Bass drop out at 75-55hz

[gene]

What disappoints me, I guess, is that it's going to be extremely difficult to persuade my superiors to purchase bass traps to put in the room.

Bass traps are NOT a necessity in most rooms. You can achieve excellent bass response by properly positioning and integrating 2 subwoofers in your room along with minimal EQing (if needed). If you still have issues afterwards, you can add passive treatments as needed but its best to consult with a professional rather than just throwing absorption in your room and eating amplifier power.

 

[Vaughan Odendaa]

Except the room in question is extremely small. Almost cube shaped. In my case, bass traps are a necessity. And I do use two subwoofers.

And I think I might agree with you that bass traps are not necessary for good sound in all cases. The operative word is "good". Adding traps can change a good room into an excellent room. Adding bass traps can only improve the acoustics of a room (even the good ones).

Your alternative of adding a second subwoofer to smooth the FR sounds like a reasonable one. I do have two subwoofers. But the room size limits my options as far as placement is concerned.

Most people have no clue what EQ is let alone how it works and how to utilize a one band parametric filter (let alone six or twelve). I guess one must just pick their poison.

Aren't professionals expensive to hire ? And isn't it possible for one to learn 80% of the professionals on Audioholics.com ? After reading a dozen of acoustic books, gaining experience using EQ and measuring your in room FR, can one be called a professional or hang with the professionals ? I think so, in my opinion.



Some of the so-called "professionals" (I won't name names) abhore the use of bass traps, some claiming that they don't work at all. Go figure.

--Sincerely,

 

[gene]

Except the room in question is extremely small. Almost cube shaped. In my case, bass traps are a necessity. And I do use two subwoofers.

And I think I might agree with you that bass traps are not necessary for good sound in all cases. The operative word is "good". Adding traps can change a good room into an excellent room. Adding bass traps can only improve the acoustics of a room (even the good ones).

Your alternative of adding a second subwoofer to smooth the FR sounds like a reasonable one. I do have two subwoofers. But the room size limits my options as far as placement is concerned.

Most people have no clue what EQ is let alone how it works and how to utilize a one band parametric filter (let alone six or twelve). I guess one must just pick their poison.

Aren't professionals expensive to hire ? And isn't it possible for one to learn 80% of the professionals on Audioholics.com ? After reading a dozen of acoustic books, gaining experience using EQ and measuring your in room FR, can one be called a professional or hang with the professionals ? I think so, in my opinion.



Some of the so-called "professionals" (I won't name names) abhore the use of bass traps, some claiming that they don't work at all. Go figure.

Yes in a square room, you must use every means possible to better your bass response. Though don't over abuse any particular method. There seems to be a tendency by some to over treat a room which is NOT a good thing.

We do teach most of what is needed to know related to home theater here, but large portion of our readers don't necessarily absorb all the info and/or have the time, patience or know how to properly measure system response and tackle room acoustics and setup stuff.

Yes I agree with you a lot of pro installers are only "pro" by name

 

[Vaughan Odendaa]

Take myself as an example. I work in an audio related field. I've read Everasts book twice. I've read two books on speaker design. And I've absorbed a lot of information. I've dabbled with EQ. I haven't spend a lot of time with it but I'm going to dedicate a whole lot of it not only because I want to increase my knowledge but because it will benefit my clients as well.

Am I a professional ? Probably not. But I'm well on my way. I'm only 23. There are some really simple concepts which I've found difficult to comprehend in some threads and conversely, the more difficult concepts I've understood like a piece of cake.

I think if people are willing to study and go the extra mile, they will be far more educated and far less reliant on "professionals". Although there are isolated cases where there are some professionals with 40 years of experience in which case I'll have to eat some of my words.

Only in that case. Heh. Your site is great.

--Sincerely,

 

[Savant]

Vaughan,

In the most general terms, the degree to which an individual is "professional" in their trade can be measured by looking at their credentials. Besides involvement in professional organizations related to their trade, licenses, training, and the rest, the most shining example of how good (or bad) they are at what they do can usually be gleaned from the quality of work they've produced. In this industry, that means how good it sounds, as well as how good it looks.

Additionally, to borrow and paraphrase from an ad on TV right now: Hacks practice until they get it right; professionals practice until they cannot get it wrong.

 

[Ethan Winer]

Folks,

The definition of a "professional" is one who makes a living at their craft. This has nothing to do with competence or lack thereof. Though maybe it should!

> Bass traps are NOT a necessity in most rooms. <

I can't think of even one professional recording studio designer who would agree with that. I'm talking about folks like John Storyk, Fran Manzella, John Sayers, and others who design million dollar control rooms and mastering suites.

> Some of the so-called "professionals" (I won't name names) abhore the use of bass traps, some claiming that they don't work at all. <

The only professionals I'm aware of with that opinion are those who set up and install audiophile listening rooms and home theaters. In that case their customers are mostly home owners and, at the high end, rich folks and sports heroes whose rooms are profiled in the popular press. Real professional designers - those who work for other professionals - tend to be more educated in acoustics. Think about it - how could anyone who owns professional room analysis software dispute the efficacy of bass traps? It's very easy to see the horribly skewed response and excess modal ringing without bass traps, and the enormous improvement after adding traps. So anyone who claims bass traps "don't work" is in denial.

That said, there's a fair amount of latitude subjectively as to what sounds good. I happen to prefer a room more on the dead side (RT60 around 200 to 300 ms), and others prefer a more live sound. Some people prefer a much more live sound. This is opinion only, and nobody is right or wrong on that. However, I personally do not put a skewed bass response or excess modal ringing in the "opinion" category because I can't see how those could ever be desirable.

--Ethan

 

[Savant]

The definition of a "professional" is one who makes a living at their craft. This has nothing to do with competence or lack thereof. Though maybe it should!

This is not the case in all industries. E.g., one cannot call one's self a "Professional Engineer" (or even simply an "Engineer" in some states) without proof of competence. A P.E. must prove their competence through experience, testing, adherence to a code of conduct, etc. Of course, this might be injecting the concept of "Professional" versus "professional" (or "Engineer" versus "engineer" for that matter) into the discussion. However, if all industries were to measure competence like the engineering industry, perhaps the world would be a slightly better place...

 

[Glenn Kuras]

Bass traps are NOT a necessity in most rooms. You can achieve excellent bass response by properly positioning and integrating 2 subwoofers in your room along with minimal EQing (if needed). If you still have issues afterwards, you can add passive treatments as needed but its best to consult with a professional rather than just throwing absorption in your room and eating amplifier power.

Gene I do agree that room set up is VERY important and this is something that we touch on with every room set we do. But I don't think I have ever been in a room that did not NEED bass traps. I am sure you could build such a room, but have not seen one yet that does not need treatment. Now if you really do not care if the bass it booming and clarity on the low end is not important to you then sure just set up and go. I myself would think that if you are going to spend 1000s if not 100,0000 on equipment going the extra step to make the room sound good should be a no brainier. Would you not agree?

Glenn

 

[Ethan Winer]

Jeff,

> A P.E. must prove their competence through experience, testing, adherence to a code of conduct, etc. <

That's a very good point. As I wrote in the introduction to my Audio Myths article in Audio Media magazine:

Most engineering fields require a college degree or at least state certification, and for good reason: If you design a drawbridge or high-rise office building, you'd better be able to back up your proposal with irrefutable science proving the design really works and people won't die. But the audio recording field has no such formal requirements. Anyone can claim to be an audio "engineer" and go about his or her business. Indeed, if you can produce recordings that sound good, nobody will argue about math or electronics theory - a great sound is all the credentials you need. Every successful audio engineer knows how to get a good sound, but the lack of a solid technical foundation prevents many from fully understanding why what they do works.

--Ethan

 

[gene]

Gene I do agree that room set up is VERY important and this is something that we touch on with every room set we do. But I don't think I have ever been in a room that did not NEED bass traps. I am sure you could build such a room, but have not seen one yet that does not need treatment. Now if you really do not care if the bass it booming and clarity on the low end is not important to you then sure just set up and go. I myself would think that if you are going to spend 1000s if not 100,0000 on equipment going the extra step to make the room sound good should be a no brainier. Would you not agree?

Of course you and Ethan have never been in rooms that don't need bass traps. You both making a living selling them exclusively

The truth is, if you use multiple subwoofers, proper speaker and seating placement, the need for bass trapping goes down significantly. As a prime example, I have no bass traps /absorption in my room (other than my riser) that functions below 100Hz and the bass response in my room is stunningly linear at all listening seats.

Bass traps are a tool to use (if needed) but NOT something that should be overly abused at the risk of acompromised esthetics, sacrificing amplifier power, and creating an anechoic type room response.

The only professionals I'm aware of with that opinion are those who set up and install audiophile listening rooms and home theaters.

Dr. Toole discusses this in his CEDIA training courses and also has several white papers on the topic of modal control in small rooms using multiple subwoofers.

 

[Vaughan Odendaa]

In the most general terms, the degree to which an individual is "professional" in their trade can be measured by looking at their credentials.

I agree with you. But at the same time, if one uses experience as a gauge to determine how professional one is in a given field, like the audio field, it isn't very consistent.

I know people who have been in this industry for 30 years and know very little technical know-how. In fact, I know quite a few "professionals" who don't actually know a thing about acoustics. So I don't know.

I certainly don't claim to be a professional to the same degree as Terry Monlick (sp ?) or Ethan Winer or some of the other well known guys around here. But learning from the best is a good reference point too.

--Sincerely,

 

[Vaughan Odendaa]

I've used bass traps in a few situations and I can't believe the difference they make. I would like some traps myself but the import duties are horrendous. But I think I might just endure and order. And I know I could probably make them myself but I'm lazy.

Glenn, did you get my email ?

--Sincerely,

 

[Savant]

Anyone can claim to be an audio "engineer" and go about his or her business.

Getting completely off-topic here, but: Legally, this is not the case in some states. Missouri, for example, requires an engineering license in order to use the term "engineer" in any official capacity (e.g., on a business card). Indiana has the same requirement, but only for state employees. In these two examples, a degree is not enough to be called "professional" let alone "engineer"! So, while one can call one's self what one wishes, officially using the term "engineer" is not allowed by non-licensed individuals in a strict legal sense in certain places. It might seem nitpicky, but such is the way of the world sometimes...

There has been heated debate about the (mis)use of "engineer" for many years in the engineering community (mostly within the NSPE), and not just because of audio "engineers." Software "engineers" also have been discussed at length as examples of persons who, in some people's eyes, are misusing the term "engineer."

Personally, I tend to distinguish - when necessary - by Engineer (big-E) and engineer (little-e).

As a final thought regarding the potential for liability: I would advise taking particular note of any audio "engineer" designing loudspeaker rigging for the local auditorium...

 

[Nick250]

Bass traps are NOT a necessity in most rooms. You can achieve excellent bass response by properly positioning and integrating 2 subwoofers in your room along with minimal EQing (if needed). If you still have issues afterwards, you can add passive treatments as needed but its best to consult with a professional rather than just throwing absorption in your room and eating amplifier power.

Gene, can the second sub be of lesser quality in a dual sub configuration? My Hsu VTF-2 sounds great in the center of the living room. It sounds boomy anyplace else I have tried. I have a Paradigm PDR-8 sitting gathering dust in a closet. I would love it if I could use the PDR-8 to allow me to move the Hsu from the center of the living room and still get nice tight low frequencies.

Nick

 

[gene]

Gene, can the second sub be of lesser quality in a dual sub configuration? My Hsu VTF-2 sounds great in the center of the living room. It sounds boomy anyplace else I have tried. I have a Paradigm PDR-8 sitting gathering dust in a closet. I would love it if I could use the PDR-8 to allow me to move the Hsu from the center of the living room and still get nice tight low frequencies.

Placing a sub in the center of the room is the WORST place you can possibly position it. Do you mean center room front wall?

When using 2 subs, its best to use subs with similar output capabilities so you don't overdrive the weaker sub which in your case would be the Paradigm. You can however experiment with close positioning to the listening area so it doesn't have to be turned up as much.

 

[Rob Babcock]

I won't pretend to speak for Ethan, but I know for a fact he DOES NOT make his living exclusively from selling RealTraps. His bio is well known and in any event easy to find. I also know for a fact that he's devoted more time & energy to giving away designs and knowledge than he spends on selling them. How many pure vendors are willing to give away virtually all their recipes/secrets for the asking?

 

[Nick250]

Placing a sub in the center of the room is the WORST place you can possibly position it. Do you mean center room front wall?

An exaggeration on my part, sorry about that. It's about three feet toward the center of the room from a side wall and four feet back from the speakers/front wall. The space is a 23 x 27 combined living room and dining room. At that spot it sounds tight and musical. If I move closer to any of the walls, the sound becomes boomy.

When using 2 subs, its best to use subs with similar output capabilities so you don't overdrive the weaker sub which in your case would be the Paradigm. You can however experiment with close positioning to the listening area so it doesn't have to be turned up as much.

I will experiment, thanks Gene.

Nick

 

[bpape]

Gene.

I would also have to disagree in part with your statements about bass trapping. I will agree that it's something not to be abused or overdone. But, they are almost always of benefit if used in appropriate ways, placement, and quantity.

I agree that proper speaker and seating placement are key to getting good frequency response. I always ask my customers to go through that exercise BEFORE putting up any treatments so we can get the best response possible from the start and then treat what's left. EQ can also help - if used judiciously.

However, those things do nothing to deal with decay time issues which, IMO are as important as frequency response issues. You can have ruler flat response in a home theater but if the decay time in the 250Hz band is up over 2 seconds (not at all unusual in a standard construction home room), you'll have dialog intelligibility issues. You'll also get the complaint " I can't hear them talking so I turn it up but then the effects are too loud." You can't EQ or position that away.

Realistically, if bass absorbers really weren't necessary, then why is EVERY professional studio outfitted with them and why are they generally the place where most of the money is spent in treating those rooms? Are they all wrong? I don't think so.

Any professional room designer knows that the entire spectrum of sound needs to be dealt with in a room from both a frequency response and decay time perspective and not just from the midrange up. Just treating from a few hundred Hz up, just dealing with reflections, and only concerning oneself with frequency response issues will leave the room sounding boomy and muddy.

I have done this for a lot of years - before starting my own company and before working with Glenn at GIK. I am a trained musician and have worked in a professional recording studio. I'm not just saying it because we're selling stuff. I'm saying it because it's true and because they work. I think my customers would back up that assertion. I've not had even 1 single person ever come back to me and say that putting in bass control in a room didn't help - quite the opposite.

An except of one of your own reviewers thoughts on this:

"Placing the GIK 244s in the corners behind the big Axiom M-80s we started the listening evaluation again. From the very start of the track “Black Cow” we found the bass more controlled, focused and tighter. As good as Black Cow sounded without the absorption material, it sounded much better with it. The difference between the untreated listening session and the treated session was fairly dramatic."

Bryan

 

[gene]

Bryan;

I don't have the time or desire to continually rehash this topic with you and Ethan. Sadly much of the misinformation about the benefits of multiple subs and equalization to minimize modal ringing on our forums seem to come from both of your websites and related postings. I have provided references countless times of how linearizing bass response in a room using multiple subs and minimal equalization will fix frequency/phase domain issues. If you fix problems both in frequency and phase, time domain issues also disappear. Its called convolution theorem. Dr. Toole as well as others have proven this in the past.

There is nothing wrong with using passive treatments (if needed), but if you get the loudspeaker to room integration correct first, the need for low frequency passive treatments goes down considerably. Most professional installations build in passive treatments into the walls so you don't have obtrusive 4" thick 2foot by 4 foot square panels in the room too.

Recording Studios have much different design goals than consumer home theaters. Most recording studios are set up for a near field sweet spot listening condition. The aim with good home theaters is to provide a wide listening area where all seats are good seats. Most recording studios DON'T use multiple subwoofers, and in fact actually use full range speakers all around which is NOT a good idea for great sound in multiple locations.

I suggest reading this little article we did on this topic:

http://www.audioholics.com/news/editorials/SurroundSound.php

 

[Audioholics]

Realistically, if bass absorbers really weren't necessary, then why is EVERY professional studio outfitted with them and why are they generally the place where most of the money is spent in treating those rooms? Are they all wrong? I don't think so.

That's an interesting argument. Let's rephrase it a bit, though and see if it works in a different scenario:

"Realistically, if Bose speaker systems really are sub-par, then why are they the second largest speaker manufacturer in the world, second only to Harman? You can find them in the most expensive homes and automobiles in America and they are the most expensive piece of AV equipment found in those mass markets. All they all wrong? I don't think so."

Well, it's a silly analogy to be sure, but so is saying that the majority of recording studios built in the 80's and 90s - all of whom disregard bass management in favor of full-range sound reproduction - is a good reason to favor bass traps to the level that is being discussed here.

We're not against bass traps, but we are careful about the emphasis on them and want their use placed in perspective - a perspective that is difficult to get from manufacturers of bass traps. We also want accurate information to be placed on these forums, so from time to time we'll interject into the hype as "the voice of reason" - not to be pompous, but to protect our readers from hearing only a contant stream of advice being given to them from people who stand to profit the most from that advice being heeded.