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What about bass? (Read 1147 times)
Chris K
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What about bass?
11/30/09 at 03:44:19
 
I'd like to start a general discussion on probably (IMHO) the second most cantankerous subject/problem in our stereo listening lives. The first being a vicious room response in the critical midrange and upper mids that has a tendency to just jump out and "bite" you in the ears.
Room treatment abound for that mess.

But this is about BASS. And that is a subject that rooms and speakers and recordings all conspire to give great puzzle and questions that arise in ones mind when some part just seems lacking in the bass or is "bloated" and overdone.
OH it's not that the bass is always bad or non-existent but just that certain places in the room suck out and others are rock solid and there is just no two ways about it. I've had some prevailing experiences which have lead me to the conclusion that speakers as good at producing great bass as all the pairs I have (6) are not the problem and have never been the problem. As simple minded and obvious as that may sound to more experienced audiophiles than myself, it is nevertheless a really vexing issue when you have a system that is doing everything right and then some piece of music you heard 100 times before fails to deliver what you expected in your mind to be the "impact" or power you thought was contained within. So you move to a boundary of the room and viola, there it is. Or at least some of it. Now this is all notwithstanding the stupendous soundstage and other goodies you've already dialed into your system. It is at least a given that you are getting some pretty palpable and amazing sound out of your equipment at this point. But I'm talking the last drop of room coupled, evenhanded, bottomless force that is in my estimation possible with as little as 5 watts if all is right.

Do you "cheat" with a well placed and dialed in sub? Or do you simply say "I guess I need a standalone custom built listening room", and proceed to tear down a wall or add a new "wing" to your humble abode. Grin At this point I've gotten "results" by moving the systems (yes systems) to different rooms and occupying different walls in those rooms with many different characteristics in bass. In all my fussing I've had moments in my home where I thought it NEVER sounded that good to me EVER. Both bass power sound stage and the whole deal. And I was not smoking or drinking anything at the time. But one thing is for sure the sweet spot has NEVER been the "bass" spot, and the bass spot while not presenting a "perfect" sound stage was and is usually glorious enough to want to listen mostly from the "bass" spot rather than the sweet spot.

If some reading this have never availed themselves of going around your listening room while familiar material is playing then do so. Go even into the corners stand, sit, lay on the floor. You will understand a lot more about what your equipment and the room are doing with one another.

I'm going to end this first post and hope to get a serious discourse going on this subject so please weigh in as you feel so inclined.
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mike_gagne
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Re: What about bass?
Reply #1 - 11/30/09 at 07:09:05
 
I like this!! I have my own revelations also but would like to hear more first.
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buzz
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Re: What about bass?
Reply #2 - 11/30/09 at 19:12:05
 
Hi Chris,

Using the Imperial bass has always been very good. Recently I moved to open baffle and bass has moved into the fantastic league. Very realistic, great imaging.

The trade off is that perceived 'slam' is not as good. I have been considering adding sealed subs tuned for frequencies 70-120hz to get it back. But for now upright bass is the best I've ever heard.
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DPC
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Re: What about bass?
Reply #3 - 11/30/09 at 19:15:08
 
Hey Chris,  Good subject.  I came to know Decware after building a House Wrecker a few years years ago.  It was as Steve described it but the bass sound was everywhere but the room where I wanted it.  After reading some of Mr. Deckerts white papers I made a trip to Peoria.  His advise in the papers is to treat your listening room for the bass frequencies first.

There are many things the we can do to improve the bass in our rooms and they are not all large and ugly.  The rewards for our efforts here are well worth the time and effort.

My listening room is and will always will be a work in progress.  I focus my efforts on room tuning far more than upgrading the actual equipment.  Nearly everything that's been done here is DYI and very inexpensive.

Some folks spend large amounts on expensive power cords and other items that may or may not improve the musical experience when a fraction of that expense spent on the room will net a larger improvement.

Let the flames begin!

dennis
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Chris K
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Re: What about bass?
Reply #4 - 12/01/09 at 03:00:08
 
No flames Denis! Nope this is just my attempt at having a shared dialogue of yours, mine and others experiences and see what comes out of it. Moving on for the moment to lower mids and upper bass. Those present unique challenges to how transparent or NOT an enclosed speaker driver sounds. That goes for bass horns as well as reflex and other resonant designs.

Open baffle is another thing and I'm glad you mentioned it Buzz! Because, (rhyme intended) I have not tried this yet on any scale that would produce well into the 30Hz region. It has been always my own experience that solid mid to low 30 Hz is required absolutely for music reproducing main front speakers. This is a point I cannot concede ever. I think that coherence of the whole spectrum down into 30 is a must in a pair of main stereo speakers Did I say that too many times?

That said referring to the upper bass region once again. If an enclosed speaker has "missing" bass in this area always they will sound a bit anemic. Transparent maybe but anemic for sure. If there is too much energy in this range (say 80 to 250 hz) you have many problems to overcome if you are a speaker enclosure. Not the least of which is resonant distortion and cabinet vibrations injecting their own sound into the room. Mind you, these are pet theories or ideas that I have no certain science to prove. I do things all the time (almost OCD) though, for example I feel the cabinet at high volumes, and watch the woofer excursion during some excruciating passages of material. Heck I've even positioned myself behind or between the wall and back of the speakers to see just what that part of the room sounds like. These little excercises tend to help me hear what is happening at the listening seat.
But I digress.

If your room and speaker position have characteristic increase or decrease in that upper bass region then the problems get really weird sometimes.

For example if the speaker is a bad example like say, a big bass reflex box from the 70's that sound rather chesty and bloated. Well in the right room that can be corrected by the rooms natural response IF your lucky. Now the bad resonance and "one noteness" of such an enclosure may still have it sounding less than ideal as far as a transparent boxless sound, still the room can and does sometimes help.

If on the other hand you have an enclosure that to my ears sound totally transparent with plenty of mid bass and deep bass, such as the pyramidal shaped radial designs Bob (Zygi) and Steve produce then that is where the room gets funny with a set of good speaker. The above example would have the speakers sounding thin but much more transparent due to the inertness and non resonant character of the cabinet structure. Nice sound but thin at the listening chair. Not saying that is what would happen. All else being equal if you moved then to a spot where the bass comes in nicely then you are positioning yourself in a sort of bass sweet spot with acceptable sound field or imaging. A compromise yes. I did this at DecFest often every year. I would pick a spot in the room that was not the center position but was where the bass was dialed in and everything seemed to be synchronized and balanced yet powerful and authoritative. NOT weak. I do this all the time at home. Take the above example with the bass reflex and move into the "bass" spot and you can get what has been termed "room boom". High bass like 150 to 250 Hz and it is a howling sound that is disgusting.

The above are hypothetical yet real anomalies I've experience in listening over many years. The extremes of bad sound have been eliminated for the most part because in the last 4 years I have been fortunate to be listening to better built, better designed speakers. Still the room messes with this nuanced and tailored sound regardless of how well appointed the speaker. I know this is to be expected in an average home environment. I've also been fortunate that all my listening spaces have multiple "outlets" if you will, such as doors, archways and open staircases that tend to evacuate spurious bass energy quite nicely. That is all well and good. I am headed toward taming all midrange and high frequency nasties with diffusors. But this is all about bass. Upper and Sub.

Open baffle bass into the 30 Hz region would be a commitment of space almost as great as a pair of Imperials IMHO. That said I know how good dipole bass can sound because Steve Deckert's Acoustats did it as good as I thing anything I've ever heard. Did it get into the 30's? Don't know. Sounds like it did. It was powerful and non resonant bliss. But it was also in a giant room and the Stats were some 8 to 10 feet from the the true room boundaries. Also anything as large as the Acoustats are going to have a "head in the vice" sweet spot and their size is a deterrent. They are an animal that needs "care and feeding".
A fast 10 or 15 inch sub driver in a door sized open baffle is even more cantankerous than those.

Besides the speakers are making plenty of bass down deep and very even and plenty of push and guts in the upper bass. Nope this is down to the goofiest part of room response and that is in the bass, both upper and sub. Any rightness in this regard and your system will "blossom" like you've never known it before. It will sweetly kick your a$$ like you never heard it before. I had moments of this sort of bliss and once it was with a perfectly dialed in sub and a second set of speakers that had the mid bass energy that was missing in the room. It was a rag tag setup that just would not stop. But it also had thing wrong with it imaging wise because it was a multi speaker set up. Instead a better thing would be to get a room right in the bass. And believe me I know how hard that is. The other time it came right is by brute force with just the main speakers. I put a solid state integrated with the Decware CSP 2 and a set of prototype Radials, which allowed tone control and down to DC bass capability. Still not an optimal setup for reasons I'll not go into. Not important. It was GOOD.  :o
But brute force is still not addressing the room problem. I say if we can get the entire bass spectrum of the room right then 3-6 watts will sound like a 1000 watts. I believe this wholeheartedly.

So commence the discussion gentlefolks!
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buzz
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Re: What about bass?
Reply #5 - 12/01/09 at 03:35:39
 
Yup I've been through all that your talking about.

After a while I ended up giving up on room treatments and going the digital EQ route. I like the Behringer 24/96 as it has time delay and phase adjustment in addition to frequency EQ. It is the 'most right' solution I have heard, much better than single driver systems even with excellent room treatment. And it is able to give you flat response into the 20's. (not that it really matters).

My issue is kick drum. There is something missing at the instant the skin is struck. I think that the high Q of open baffle drivers lacks that concussive 'thwack' a tight low Q driver has. Open baffle bass is superior in every other regard but this.

I have decided to add two pro JBL 2226 15" woofers to my system in addition to my open baffle woofers. The JBL have a low Q and are very fast. Mounting them open baffle should give me back the kick drum. I will re-EQ to be flat to 30hz.
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DPC
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Re: What about bass?
Reply #6 - 12/01/09 at 11:19:23
 
For an example of the OB experience see what our friend Randy has done.
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buzz
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Re: What about bass?
Reply #7 - 12/01/09 at 13:47:24
 
Randys OB sub at the fest 1+ years ago is what forced me into this. I couldn't believe how such a simple solution sounded so real. My setup is the same but I have added the digital EQ, and now will be adding the JBL's to that.

Listening to jazz / acoustic instruments there is no need for the JBLs, nothing is missing. However, I have this techno / classic rock addiction I've been fighting for years. Wink
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DPC
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Re: What about bass?
Reply #8 - 12/01/09 at 19:54:13
 
And, at that time Randy did not have the the new servo plate amps.

My setup is similar and have been able to flutter my pants legs when trying.
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DirtDawg
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Re: What about bass?
Reply #9 - 12/02/09 at 21:16:23
 
Buzz, you may be onto something, because the relatively low Q, JBL drivers that I use (twin fifteens in each baffle - 0.29Qts - the best of my ability to measure, as opposed to a Qts of 0.7 - published specification - for the Dayton) are quite a bit more realistic sounding and, I suspect, more accurate than the higher Q Dayton fifteen's (originally designed as Infinite Baffle woofers, in theory) available from Parts Express.

I believe it has most to do with a driver's ability to simply follow a waveform accurately - yes these things jump, sometimes, but what the Dayton's did that offended me was, once they jumped they continued to resonate a bit, well beyond what a typical heavy-slapped drumhead would do, while the JBLs seem to instantly damp themselves.


OH, I can identify with the classic rock need. (Check out Chickenfoot, if you haven't already!  They're a small, newly conceived band of well-known professionals)
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buzz
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Re: What about bass?
Reply #10 - 12/03/09 at 01:00:38
 
Dawg, I didn't know you were running OB!

Do you have any pictures? I am very curious about your setup!  

(And thanks for the music tip Wink)
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dank
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Re: What about bass?
Reply #11 - 12/03/09 at 01:02:20
 
Is the "bass spot" in the same location as the "sweet spot" if you have your system set up outdoors (i.e. no room reflections)? Assume any reflections from trees, rocks, etc can be ignored - although I guess the ground would have to be accounted for???.

DanK
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Steve Deckert
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Re: What about bass?
Reply #12 - 12/03/09 at 02:47:47
 
Dank,

Having perfect bass response at the sweet spot is far more likely to happen outdoors than in a square structure.  However, with no room gain the bass may sound light by comparison.  My experience is that if the source of the sound, ie speakers is backed up by a solid structure (stage or hill) so it has something to project from it is indeed perfect.

I can remember well some small private outdoor concerts under the moonlight that had some of the best bass I've ever heard.

Steve

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Chris K
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Re: What about bass?
Reply #13 - 12/03/09 at 04:04:13
 
Well Dan I've been intrigued by that idea but with the weather changing for winter I'll not go there just now. I know it will sound thin.
BTW I just started doing frequency sweeps and I have to make some test sweeps on the computer. I've some free tone generators and it's crazy how ragged the room response is even in the bass. I got to break up the test sweeps into manageable bands and have them repeat a few times. Do one speaker on then the other and both at same time. I'm thinking this will shed light on the subject but still no solution.

Are some of you saying that a well integrated OB sub would fill in the room bass "dropout" points. What about hot spots? Taming "nodes" in the room is weird science. I guess any boundary with parallel surfaces and 90 degree angles forming cubic corners is going to play hell with the sound no matter what. Steve had mentioned about his old reference room at the Spring Street shop as having some several thousand pounds of mass added to the walls by attaching the giant MDF quadratic diffusors and sheetrock to the room. All bringing down the resonant room frequency to lower levels so that mid bass was smoothed out and deep bass solidified. Mass to the walls? is that something to consider. Sandwich material using two layers drywall with a softer compound between?
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