I have an Arcam SA-20 integrated amp, B&W CM5 speakers and an SVS SB1000 sub. I previously had 20 yr. old B&W DM602 speakers. I sold them. The 602's 7" drivers were great with bass but lacked in other areas. The CM's (6.5" driver) are much better in midrange and treble but I'm having trouble getting the bass dialed in. They can get a little boomy and lack a clean drum punch like the 602's had.
I've got them 26" from the rear wall and am using the outer foam plugs in the ports. You can plug the entire port or take out the middle part and just use the sleeve. I've spent days inching the stands around, toed in, not toed in. I was using an AVR as a preamp with the 602's so I had crossover capability. With the Arcam I don't. I'm a little lost without that feature. The CM's sound best when I can cross them over at 80Hz. Do I have options to manage bass like an outboard crossover or something else?
I’m not advocating 2 subs, as in one sub for left and one for right, for brian-holmes 2 ch system. All bass below about 80 Hz cannot be localized (we cannot tell specifically where it’s coming from) and is perceived as mono. I’m advocating the OP use 2 subs in his room with both subs operating in mono and optimally positioned in his room, and in relation to his listening seat, via following the ’sub crawl’ positioning method. The reason I’m suggesting that he use 2 subs running in mono in his 2-ch system is the following:
1. Positioning each using the ’sub crawl’ method will ensure there are no standing bass sound waves, which are heard as bass over emphasis (a peak), bass under emphasis (a null) or the absence of bass (a cancellation), at his designated listening seat. 2. He will perceive the bass, even in mono, as powerful, solid, fast, smooth, dynamic, detailed, with a sense of ease, that is natural and seamlessly integrated with his main speakers. 3. Bass is cumulative in a room and utilizing 2 subs means the output capacity is doubled, the bass will be as powerful and dynamic as the source material calls for and there’s minimal distortion and a sense of ease since each sub is operating well within its limits. 4. Although each sub is operating in summed l+r mono, the bass will still be perceived as a form of stereo bass since the subs are reproducing the fundamental bass tones below 80 Hz, that cannot be localized and are in summed mono, but the main l+r speakers are reproducing the harmonics or overtones of the fundamental bass tones above 80 Hz, that can be localized and are in stereo, Our brains are able to associate the mono fundamental bass tones with the stereo bass harmonics or overtones of the fundamental tones and, thereby, localize the fundamental mono bass tones under 80 Hz. This process allows the proper perception of deep bass instruments within the stereo sound stage illusion. For example, deep drums are perceived as being located in the rear center of the sound stage and an upright bass is located at the front left of the sound stage. 5. The stereo soundstage illusion is enhanced, being perceived as wider, deeper, more realistic and 3 dimensional.
These are the benefits of utilizing multiple subs, reproducing summed l+r mono bass, in a 2-ch system. Two subs will provide these benefits at a single designated listening position and 3-4 subs will provide these benefits throughout the entire room, which is useful if multiple seating positions exist in the room.
It’s the sub that’s boomy and most likely not the speakers. Still don’t understand why people use subs in a stereo 2 channel set up. Maybe in a home theater, but no way would I consider one in my 2 channel dedicated set up. My tannoys produce plenty of bass as is. To me, the use of a sub to compensate for lack of bass is weird. I’d just buy a pair of speakers that does bass well. Jmo...
I agree. I'll get it figured out. I'll read up on the Vandersteen method. Thanks. I can get another sub. I have room but my models grill has been changed/discontinued and can't purchase just a grill. I'm more than a little anal about things. I do weekly searches for an identical used one.
1. I used the Vandersteen method to position my speakers. It is available on their web site. You basically divide the distance from the rear wall and side wall by prime numbers. 3,5,7 etc. You can use these results to set your speakers to work around your room limitations. You will need to find the center of your speakers to measure these distances. I would use the port plugs in their default if that is such a thing to start with.
2. Multiple subs will help with bass boom or peaks and nulls. At least two will solve some of your problem. The DBA is a great solution if you have $$$ and room. You could get another of the one you have and notice great improvement. In my case they are between my speakers firing toward the front wall. Others recommend having them near your listening position, so you will need some longer cables??
3. Room treatments as much as you can work into the decor. I used GIK and was surprised that all the bass traps, diffusers and first reflection panels are bass traps as well. This not only helps your bass but will improve imaging and soundstage. Cost was about $1500 for me.
4. You should have volume adjustment on your sub and not need an external crossover.
Your problem isn’t as "bad" as you think. I my situation I thought I already had good bass, but afterwards I could hear much more detail in the bass notes which surprised me. I did not go to the effort of using a mike and program. i figured I would be forever tweeking.
It seems like you're receiving some elaborate advice on possible solutions. I just thought I should chime in again and let you know it's highly unlikely that any drastic action, such as disconnecting the bass section on your main speakers, will be required. The most elaborate possible solution I would suggest you even contemplate trying is utilizing a pair of subs rather than just one. If your budget is low, however, I would suggest trying the possible solutions that cost the least or nothing first. For example, my earlier advice to try repositioning your existing sub utilizing the 'sub crawl' method. Please resist taking any elaborate. drastic or costly action at this point in your search for a viable solution.
YES, the problem would be could you produce enough Mid Bass 100-250-300 hz range.
Again, if your not squeamish (purest) about an EQ, or inserting an active OX (300.00 usd) like a Behringer 2496 in between the signal path. That will cure it all very quick, with ALL the goodies, DSP, on the fly correction, la-te-da.. Then you can do what ever you like.. MAGIC..
@brian_holmes, You ask a good question, and I asked myself the same question before responding above. I don't have intimate knowledge of either speaker, so I can't answer definitively. I'm going to assume that both speakers are well designed and capable of producing tight bass. I'm also going to assume that by boomy bass you are talking about inarticulate one note bass, ala cheap bass reflex designs from back in the day.
One possibility could be some sort of Speaker Boundary Interference Response difference between the two speakers. Do the two speakers crossover at the same point, and are the woofers mounted at the same height? Is their -3dB response at a similar frequency? Are the CMs in exactly the same position the 602's were? Inches can matter. Has your main listening position changed at all? Have you changed the position of any other furnishings in the room?
This tool could provide you with some insight. Compare the two speakers using the calculator and see if anything stands out. http://tripp.com.au/sbir.htm
But, without a way to measure what your room and speaker are actually doing, it is tough to mitigate the problem. It is pretty much always true that a change in position of either speaker or listening position will make some aspects of speaker room interaction better and others worse. Moving stuff around is therefore a tradeoff. What you need to do is measure the system as it currently stands, and look carefully at REW waterfall plots. You need to understand the correlation between what you are hearing with your ears and what you are seeing with your eyes when looking at the plots. What I am guessing you will see is a nice smooth decay of frequencies above 200-300 Hz, so that those higher frequencies do not persist at a significant dB level longer than 300-400 milliseconds. But below 200-300 Hz, my guess is that you will see some frequencies persist much longer than 300 ms. This is ringing. I've seen frequencies that will not decay for even 1 second or more. This sort of behavior is not going to allow satisfying bass response. Once you take enough measurements with speakers and listening position moved back and forth, you will have an understanding of which peaks and nulls are due to speaker and listening position, and which ones are due to room dimensions. You can't change your room dimensions, but you can change the position of speakers and listening position. Sometimes you can move a speaker boundary null into a room dimension induced peak, thereby causing them to offset one another.
It is just a pure guess on my part, but I see no reason to think that the CM's are not well designed speakers that are not inherently unsuited for use in your room. So it comes down to determining optimal positions first and adding supplemental treatment second. But don't discount the Swarm system. It's just physics. A DBA is "the right way" to address the problem, if at all possible.
You need a way to block from whatever UP, you cannot control on the way down. SO if you only have control from 80 down, you need to cut from 80 down on the mains.. That make since? The boom will go away... Simplest way to make it work. Or disconnect the bass section on the mains all together and see if the subs, will go high enough, Gotta be able to match it one way or the other or BOOM BOOM, in the ROOM ROOM.
One or the other, unless you want to stuff an EQ in the signal path, then it's real easy.. OXO 2496 something like that..
I get all that. What I don't get is why a better pair of speakers (same brand, similar drivers) in the same location, same room, no changes to the room are giving me problems while the cheaper pair didn't.
Getting a speaker to sound good on a particular room is ~ 90% getting the 20-300 Hz region in good shape. This optimization involves too many variables that are not fully independent. Unless you have a very favorably designed room and a speaker that happens to be designed well for your particular room, getting things genuinely optimized by ear is about as likely as winning the lottery. You might get lucky, but REW makes the task significantly easier.
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One of the FEW that actually mention 20-300 controls 90% of the overall problems of SQ of a given room..
I’m glad, I was beginning to think, I was singing ACAPELLA. A person of distinction indeed. I thought it was a dream. The FIRST, I can remember actually that explained, the "squat and grunt" DBA method is good, but some thing come first, to make it GREAT... I really don’t think that is addressed very well, or enough!!!
If anyone has read my babbling they know I’m about, room treatment first (as much as you can stand). 2nd columns, RULE. 3rd bass everywhere does not equal great bass where your setting, and listening. It means BASS everywhere. Not through my rump, but in my chest.. BIG difference. Through your bottom, is what annoys the heck out of EVERYONE else, in the house including having to control all the issues with source vibration, Valve (tube) vibrating and distorting, TT, CD.
60-300 hz is BASS it is different, DIRECTIONAL, comes to mind...
@brian_holmes, My Marantz SA15S2b SACD player weighs in at 29.8 lbs and it's base can deflect small caliber bullets and yet, the results has me listening to all of my CDs again, especially the ones I couldn't get through anymore.
If you do decide to go that route, be prepared to experiment with placement as moving an inch this was or another will elicit different sounding response.
Thank you for your responses. Much appreciated. Trying to figure out this science is challenging. I didn’t have this issue with my previous speakers but I guess other speakers is the operative term.
I suggest you try repositioning your sub in your room, and in relation to your listening seat, by using the 'sub crawl' method (you can google it). This will ensure you're listening seat isn't located near any bass standing waves, which can make the bass sound under or over emphasized or even non-existent at specific room locations.
If your source is a CD player, just get some Isoacoustic Orea footers and some more for your amp. The focus you'll get will eliminate the boomy bass resulting in some pretty dramatic focus, clarity and impact.
Boomy bass is usually due to ringing. You have bass modes that are not decaying in a reasonable (less than 300-400 millisecond) time frame. You've gotten good advice. Download REW and learn to use and interpret the REW plots, especially the waterfall plot, impulse graph, and frequency response. Get your speaker and listening position optimized for the flattest possible frequency response below 300 Hz and get those decay times under control as best you can.
Then consider a Distributed Bass Array like an Audiokinesis Swarm. I ordered a Swarm and am still waiting for delivery. Soon, I hope. The Swarm is quite reasonably priced for what it is and what it does.
Finally, add traditional room treatments if after all of this you still have ringing that gives you a perception of boomy bass.
Getting a speaker to sound good on a particular room is ~ 90% getting the 20-300 Hz region in good shape. This optimization involves too many variables that are not fully independent. Unless you have a very favorably designed room and a speaker that happens to be designed well for your particular room, getting things genuinely optimized by ear is about as likely as winning the lottery. You might get lucky, but REW makes the task significantly easier.
you need to run a room freq plot as your system is currently configured and see what the speakers and sub in the room are currently doing. Once you have that data, you can determine what you need to adjust to get a flatter response.
Dont be surprised to see some pretty wild swings in SPL output level vs. frequency. Few rooms are flat.
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