Hello, right thank you for your reading. Here's my question about a tower configuration I'm planning to build for using in my living room in a certain position.
In the past, I've already built other floorstanding speakers, always two way with one 8'' woofer placed right under tweeter, for an overall height of about 1 meter: my struggle was born because I couldn't ever obtained any good bass response from them in my typical listening position. To listen some bass I've had to go in other rooms or better on the upper floor! Only using a sub against the angle floor/rear wall (away from edge with other walls) I could obtain good basses, but I don't want to use a sub.
So I'm planning to build some new woofer design and I liked Jim Holtz's Statements II or Anthology (in the version with the same drivers of Statements II, which somebody already built and called 'Statements II remix'), the first WMTMW and the second WWMTM.
What I'd want to know from you is what of those may give better bass response in my room: the first because has two woofer near the floor or the second because has two woofers far from each other and distributed in the vertical space?
I must say that positioning them at 60 cm from the rear wall is a bit bothersome because I've children and I'll move speakers forth and back when listening, but really I love basses and I couldn't find good design able to do that staying against the rear wall. In case please could you suggest me any? I'd like to experiment some high efficiency design, as horn or TL, important is the bass response!
Thank you very much.
In the past, I've already built other floorstanding speakers, always two way with one 8'' woofer placed right under tweeter, for an overall height of about 1 meter: my struggle was born because I couldn't ever obtained any good bass response from them in my typical listening position. To listen some bass I've had to go in other rooms or better on the upper floor! Only using a sub against the angle floor/rear wall (away from edge with other walls) I could obtain good basses, but I don't want to use a sub.
So I'm planning to build some new woofer design and I liked Jim Holtz's Statements II or Anthology (in the version with the same drivers of Statements II, which somebody already built and called 'Statements II remix'), the first WMTMW and the second WWMTM.
What I'd want to know from you is what of those may give better bass response in my room: the first because has two woofer near the floor or the second because has two woofers far from each other and distributed in the vertical space?
I must say that positioning them at 60 cm from the rear wall is a bit bothersome because I've children and I'll move speakers forth and back when listening, but really I love basses and I couldn't find good design able to do that staying against the rear wall. In case please could you suggest me any? I'd like to experiment some high efficiency design, as horn or TL, important is the bass response!
Thank you very much.
Hi,
I fear this is more related to room than the type of loudspeakers you'll built ( this is not entirely true as you pointed vertical distribution of bass source may help).
Have you tried simulate your room/loudspeakers SBIR/ sweetspot position?
You may encounter a case where floor bounce and other reflections combines together to make the upper bass 'hollow' sounding.
Anyway worth spend 1hours with this and see what it tells you:
SBIR calculator
About the layout i would favor a WmtmW but i'm biased toward point source preference and symetric behavior about vertical directivity.
A WWMTM could be great too but it'll depend of some design choice criteria ( xover freq, size of drivers,...).
I don't see why an onwall or close wall wouldn't works, quite the opposite in fact( if taken into account during design).
I fear this is more related to room than the type of loudspeakers you'll built ( this is not entirely true as you pointed vertical distribution of bass source may help).
Have you tried simulate your room/loudspeakers SBIR/ sweetspot position?
You may encounter a case where floor bounce and other reflections combines together to make the upper bass 'hollow' sounding.
Anyway worth spend 1hours with this and see what it tells you:
SBIR calculator
About the layout i would favor a WmtmW but i'm biased toward point source preference and symetric behavior about vertical directivity.
A WWMTM could be great too but it'll depend of some design choice criteria ( xover freq, size of drivers,...).
I don't see why an onwall or close wall wouldn't works, quite the opposite in fact( if taken into account during design).
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Agree with Krivium. Good bass reproduction in normal living rooms (in practice) requires distributed LF-sources, mostly addressed to as a multisub setup. This kind of setup mitigates the problems that come with standing sound waves in your room. An alternative that might work is a double bass array, but that also consists of more than two LF-sources.
Your point on WMTMW is right though, spacing two woofers (and accompanying reflex ports) helps reducing the vertical room modes.
Your point on WMTMW is right though, spacing two woofers (and accompanying reflex ports) helps reducing the vertical room modes.
I didn't know SBRI, thank you very much for this suggestion, really interesting.
Please do you know some interesting project designed on this criteria and so able to sound well when placed near to the wall?
I know one commercial TL/folded horn with a high position back mouth designed (reading its presentation) to stay close to the rear wall so that interacts with the internal horn, but it seems to have a F6 of 40 Hz, I'd prefer some more extension..!
Thank you, so it could be perfect for me a WMTMW project designed to stay close to the wall, do you know any?
Greets!
What you ideally need to do is figure where the major room modes are in 3D.
For instance, the Statements II's upper woofer is near the floor/ceiling's strongest dip/'suck out' [even harmonic] at 2.73/2, so a bad plan, i.e. we normally want our speakers, listening position in a room's peak [odd harmonics] that's rarely a consideration in DIY builds for a variety of reasons.
Not enough info WRT to the original's poor performance other than at a ~ 0.8 driver center/2.73 = .293, pretty close to a 1/3 harmonics' 0.333, so possibly it's a listening position and/or floor bounce 'thing'.
Anyway, as you can see from just this little bit it can take a considerable effort to design a large multi driver speaker to blend into a room, especially an odd shaped one like yours.
I take the issue the other way around: what does happen when i put loudspeakers close to a wall and at extreme case: inwall?
For the extreme case you change the radiation of loudspeaker from 4pi ( omni) to 2pi ( hemispheric).
What does it change? As the output power radiated is the same but the space it is radiated into divided by 2 and the energy have to go somewhere: you then face the inverse of Baffle step loss: a gain in the low end of 6db.
The issue is it's difficult to know from which freq. Usually it is assumed to be around 200hz for inwall.
Same thing happen to 'on wall' or close wall with lesser amplitude. Except there you can deduct the freq where it happen ( center freq of BSC applied in the xover - if any applied). From there you can built a filter ( low or high shelf with 4 octave spread with center freq in the middle) to compensate this.
About wmtmw i repeat i'm biased. I like Dunlavy loudspeakers for example. Other answers are valid too it's just a matter to identify the important design criteria and follow them imho. Easier to say than to do but it's a target.
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A good way to excite all room modes is to position the source in a corner of two walls and floor or ceiling (rectangular room). Second best: pick a corner but lift the source from the floor, third: place the source near to one wall, floor or ceiling, but away from others.
Question is: why try to excite them. Imho that’s not useful. Even from a perspective of dsp-ing the rough ride away.
A WWMTM array would excite modal behavior more so than a WMTMW. Floor bounce artifacts btw mostly appear at (much) higher frequencies, so I do not follow that comparison.
Question is: why try to excite them. Imho that’s not useful. Even from a perspective of dsp-ing the rough ride away.
A WWMTM array would excite modal behavior more so than a WMTMW. Floor bounce artifacts btw mostly appear at (much) higher frequencies, so I do not follow that comparison.
Yes agree.
That said a WWMTM could be designed using some tricks that could be of interest on other area of the design: a side located push push sub way ( up to 70hz max) could solve most issues related to box walking and vibrations and would not induce directivity abheration ( mostly omni). And if you stay within 1,3m ctc distance between W and M/M's drivers it should sum well.
Could help from a visual aspect too if you like slim tall trading width for depth floorstander.
Win somewhere, loose somewhere...
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Guess ya'll never had a floor bounce reflect behind the LP with all the attendant out of phase reflections that can occur.
You wouldn't be suggesting the response below the midband increases in level? All that ideally happens is that the baffle step doesn't happen (considering the effect of only one wall).
But nooooo, that sure was a ceiling bounce 😛
With woofer height at about 0,5m and listening on -say- 3m the floor bounce dip would start at 750Hz, of course dependent of the definition of a dip. In a 3-way one would not cross that high…. And still, a WMTMW would even mitigate floor and ceiling bounce comb filter effects, wouldn’t it (unless clumsy chosen dimensions come at play)?
Didn't do any math, but have 'cured' mass quantities of reflections for high mounted woofers that the Sony pro cinema designer/installer I was working with said was 'floor bounce', a reflection I'd no clue about in '92, only the usual eigenmodes plus some I couldn't account for. As for ceiling bounce, this was a large auditorium with only the usual eigenmodes.
I think i made a short cut as usual.
Let me rephrase it: for a loudspeaker whose initial design target was a flat frequency response in free space, once you use it in/on wall* you you'll see a 6db gain in the freq range where bsc usually happen.
Does it sound better this way Allen? Or have i missed a nuance or what you was pointing in your question?
*in EU ( well in the EU's country where i've had contact about this) we made a difference between soffit mounted and inwall.
Inwall need a hardwall ( cement, stones, whatever but plain and massive) with a sealed cavity in it to accept loudspeaker box ( or the cavity is the box) and the massive wall is usually decoupled from the rest of the structure ( and another decoupling stage could even be applied between loudspeaker and cavity).
I've seen it implemented this three time in my life.
Soffit usually mean something like this ( the Quested monitors): Google Image Result
The difference may not be obvious but there is: soffit doesn't present the advantage an inwall ( infinite baffle) have about edge diffraction. To be honest for my twisted mind soffit is just onwall located near ceiling...
Markbakk,
My mains monitors are 15"+4"+1" initially crossed passive at 750hz and 4,5khz! Some did x that high! And it is mostly ok ( there is drawback like with allchoices but this loudspeakers have good quality to me) 😀
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Hello, I'll try to summarize given this thread has become really more interesting than expected, involving a variety of aspects, too difficult for my limited knowlwdge.
Quoting some replies:
And more..
So these are the answers to the first of my questions, let's go to the second, equally important, the distance from front wall.
If I don't go wrong, if I build a speaker as the mentiond ones, WMTMW or WWMTM, for which recommended distance from front wall is about 60 cm, wouldn't it be negatively interact with its reflection being driver at about 100-110 cm and producing a dip at about 80 Hz (the missing 'thump' of which SBIR speaks about)?
Why the biggest majority of commercial speakers are made to be put at similar or bigger distances when in a living room it would be better to put them close to the wall? Do you know a WMTMW or WWMTM designed upon this criteria?
All I ask is: given this is a fundamental aspect of the sounding capability of a speaker, wouldn't it be present among the main specs of every one??
I'm sure that with the right design it couldn't be impossible to obtain a speaker sounding good in my room if close to the wall.
Really thank you.
Quoting some replies:
So WMTMW is a good choice for this reason, given also that..
Does this confirm the ability of a WMTMW to interact less with room than WWMTM? Am I right? But..
Does this means that even a WMTMW as Statement II may interact negatively with a room like mine? Do you think it may be better a WWMTM, as..
And more..
what's a 3d rendering? How can I make a simulation?
So these are the answers to the first of my questions, let's go to the second, equally important, the distance from front wall.
If I don't go wrong, if I build a speaker as the mentiond ones, WMTMW or WWMTM, for which recommended distance from front wall is about 60 cm, wouldn't it be negatively interact with its reflection being driver at about 100-110 cm and producing a dip at about 80 Hz (the missing 'thump' of which SBIR speaks about)?
Why the biggest majority of commercial speakers are made to be put at similar or bigger distances when in a living room it would be better to put them close to the wall? Do you know a WMTMW or WWMTM designed upon this criteria?
All I ask is: given this is a fundamental aspect of the sounding capability of a speaker, wouldn't it be present among the main specs of every one??
I'm sure that with the right design it couldn't be impossible to obtain a speaker sounding good in my room if close to the wall.
Really thank you.
you should consider doing some in-room freq resp tests.
you might find that using those results plus some eq may yield a good compromise.
you might find that using those results plus some eq may yield a good compromise.
@ krivium, perhaps I was seeing it from a speaker design point of view and you were seeing it from a placement point of view. I'll save the being pedantic for another day 😉
Hi,
A good read about loudspeakers location to front wall:
Monitor Placement - Genelec.com
Andreaemme, could you update your initial sketch with following info:
_ your room: the exact location of loudspeaker front to wall, and loudspeaker center to closest adjacent wall,
_ your loudspeaker: width, depth, driver diameter and height center driver location,
Thank you.
AllenB, 🙂
A good read about loudspeakers location to front wall:
Monitor Placement - Genelec.com
Andreaemme, could you update your initial sketch with following info:
_ your room: the exact location of loudspeaker front to wall, and loudspeaker center to closest adjacent wall,
_ your loudspeaker: width, depth, driver diameter and height center driver location,
Thank you.
AllenB, 🙂
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