Would this room work as Infinite Baffle? And other questions.

[Kreshna]

I'll have to remodel my house sooner or later, so it's a good chance for me to build a small, dedicated room for listening purpose. My "mainstream speakers" --JBL 120Ti mains, JBL 4410 center, and JBL LX 44 rears-- will not belong in the said room, by the way, they should go the living room's HT setup instead. There is nothing wrong with those JBL titaniums. They are tonally great, and they sound sweet when driven by tubey-sounding amplifiers like Sansui amps. However, they seem to lack soundstage depth. Thus, the purpose of this dedicated listening room is for experimenting and tinkering around with DIY speaker designs and positioning, to achieve the soundstage depth I'm craving for. Perhaps I would try Jim Holtz's Finalist loudspeakers (which is said to have really deep soundstage), perhaps I would try Fostex FE206En in double bass-reflex enclosure and see how deep the soundstage could projected by point source, single-driver speakers. All of this would be performed in this new room instead of the living room.

Originally I wanted the room to be 3 meters wide x 5 meters long, with speakers placed along the short wall to arrange their placement according to Cardas Golden Ratio. However, I'm thinking about building 3 x 3 room instead, where I could install full range single driver on the wall instead of having speaker boxes; effectively making the room an infinite baffle enclosure for the drivers. I am particularly interested to have Audio Nirvana Super 12 Ferrite for the drivers, but Audio Nirvana Super 8 Ferrite should also be okay.

The room; will it work as infinite baffle?

Of course, the room is not a true infinite baffle. In fact, nothing is, isn't it? As you see from the picture above, the room doesn't seem to completely isolate the drivers' forward radiation and rear radiation, since the room must have a door for me to get in and out. And even with the door closed, there will be a vent hole above the door for me to breathe.

However, the room is adequate to serve as infinite baffle, isn't it?

I also wonder about some other things:

1. Yes, most infinite baffle implementations are for subwoofer, but would IB work great with full range single driver as well?
2. How would infinite baffle change a driver's frequency response? Would "bass-lean" drivers like Fostex FE206En benefit from IB?
3. Does infinite baffle have deep soundstage? Since the loudspeaker drivers are mounted directly on the wall, then it would be like soffit mounted speakers in recording studios. I remember reading somewhere that such mounting eliminates the cancellation reflection from the front wall (the wall behind the loudspeaker), because the front wall becomes the baffle. I guess the elimination of front wall reflection will result in deep soundstage, but am I correct? Or perhaps I'm wrong?

 

[Kreshna]

Um... help?

 

[damacman]

By definition, a driver is considered to be in infinite baffle when the volume of the enclosure in which it is mounted exceeds its Vas. Choosing drivers that work well in IB arrangements can be tricky but the results rewarding.

I think you should focus first on the acoustic properties of the room you're designing. For that, you may choose to consult a specialist in the field before going any further. It is certainly possible that person exists here at AK, but I've not personally seen discussions here around this topic.

 

[Kreshna]

By definition, a driver is considered to be in infinite baffle when the volume of the enclosure in which it is mounted exceeds its Vas.

Indeed. And in the said room above, the volume of the "enclosure" (which is the space outside of the room) should exceed 10 times of Vas of most drivers. However, an IB should also properly isolate the front radiation from the back radiation. Considering the room has a door behind the listening position, would sufficiently long sound waves from front radiation and back radiation cancel each other as they meet around the door hole?

Choosing drivers that work well in IB arrangements can be tricky but the results rewarding.

What kind of driver suitable for IB? What the worst could happen from using inappropriate driver?

I think you should focus first on the acoustic properties of the room you're designing. For that, you may choose to consult a specialist in the field before going any further. It is certainly possible that person exists here at AK, but I've not personally seen discussions here around this topic.

I just wonder whether soffit-mount/wall-mount speakers have great soundstage depth or not. Do they?

 

[damacman]

None of those questions have easy answers. Most guidelines towards driver selection are geared towards the Qts of the driver. I've had excellent luck with large drivers with large motors and overbuilt suspension, regardless of Qts.

This I can say - I've spent weeks finely adjusting the position of loudspeakers in a given environment in an effort to achieve the best results at the listening spot. The end result is often drastically improved over the initial result. If you elect to mount the speakers in fixed locations, you'll eliminate that tweak entirely.

 

[Kreshna]

None of those questions have easy answers. Most guidelines towards driver selection are geared towards the Qts of the driver. I've had excellent luck with large drivers with large motors and overbuilt suspension, regardless of Qts.

This I can say - I've spent weeks finely adjusting the position of loudspeakers in a given environment in an effort to achieve the best results at the listening spot. The end result is often drastically improved over the initial result. If you elect to mount the speakers in fixed locations, you'll eliminate that tweak entirely.

I see. Does wrong position outweigh the (allegedly) excellet soundstage depth of flush-mount?

 

[JRhoBurton]

Check out Cult of the Infinitely Baffled.

http://ibsubwoofers.proboards.com

They define IB as back volume 10 times Vas, or more. Lots of good info here. I have 4x Speakerlab W1208R woofers with about 100 cu ft behind.

I think you are looking at two issues:

1-Does IB work well for subs?

2-How do in-wall speakers sound (operating above bass frequencies)?

IB subs can sound great if done right.

I have only done in-wall or in-ceiling speakers for multi-room casual listening. From what I have read, people who have tried it for main speakers often find the sound very flat and two-dimensional, the opposite of what you seem to be seeking. I will try to find a link or two if I get time.

 

[Kreshna]

Check out Cult of the Infinitely Baffled.

http://ibsubwoofers.proboards.com

They define IB as back volume 10 times Vas, or more. Lots of good info here. I have 4x Speakerlab W1208R woofers with about 100 cu ft behind.

I think you are looking at two issues:

1-Does IB work well for subs?

Well I actually wonder if IB work well with full range single drivers like those of Fostex or Audio Nirvana.

2-How do in-wall speakers sound (operating above bass frequencies)?

Indeed. I wonder if flush-mounted speakers --like those in studios-- have excellent soundstage depth.

IB subs can sound great if done right.

I have only done in-wall or in-ceiling speakers for multi-room casual listening. From what I have read, people who have tried it for main speakers often find the sound very flat and two-dimensional, the opposite of what you seem to be seeking. I will try to find a link or two if I get time.

I see. So I better go for Cardas placement, no?

By the way, could anyone recommend speakers with deep, 3-dimensional sound stage? How about Jim Holtz's Finalists?

 

[damacman]

Check out Cult of the Infinitely Baffled.

http://ibsubwoofers.proboards.com

They define IB as back volume 10 times Vas, or more. Lots of good info here. I have 4x Speakerlab W1208R woofers with about 100 cu ft behind.

While I get the gist, you can't redefine a term with a pre-existing definition.

 

[damacman]

I see. Does wrong position outweigh the (allegedly) excellet soundstage depth of flush-mount?

Absolutely it does. To date, the very best soundstage depth I've heard were from a pair of big Dunlavy speakers set out about 1/2 way into the listening space. Completely impractical, but wow.

I'm not sure I've ever heard a pair of high end speakers flush mounted into the wall - at least not a flat one as you've drawn,

 

[audiomagnate]

Absolutely it does. To date, the very best soundstage depth I've heard were from a pair of big Dunlavy speakers set out about 1/2 way into the listening space. Completely impractical, but wow.

I'm not sure I've ever heard a pair of high end speakers flush mounted into the wall - at least not a flat one as you've drawn,

That's how I set up my speakers. I kept inching them outwards until now the radiating surfaces are now almost ten feet from the back wall. Musicians never stand with their backs up against a wall, do they? In short, flush mounting anything but a subwoofer driver is, IMO, a really bad idea.

IBs are for subs. Multiple 18s are the usual way to go but if you don't listen crazy loud you can get away with a pair or even one. Once you go IB you will never go back.

 

[JRhoBurton]

While I get the gist, you can't redefine a term with a pre-existing definition.

Where is the pre-existing definition?

 

[JoeESP9]

A square room is very bad for sound. It's also very difficult to tame the room acoustics.

 

[Kreshna]

I see. So I better go with Cardas Golden Ratio instead of IB full range single driver, do I not?

What speakers are best for soundstage depth, then? I've been recently interested in Finalists loudspeakers, but do they live up the hype?

Jim: The Finalists offer the same huge atmospheric soundstage and layered depth the Statements are known for. Depending on the recording the
performers begin at the rear of the speakers and are layered to the rear and sides with the soundstage extending well beyond the width of the speakers if
recorded that way. The speakers disappear leaving only the performance. BIG sound from small speakers.

If it's true, then Finalists are what I've been looking for. Anyone experienced with the model?

 

[Dennis Gardner]

Moving speakers around within a room to achieve sound staging is much easier that moving walls around within the house to achieve it.

I would not use in-wall speakers as a first choice for creating a sound stage. i would consider open baffle designs for experimenting with the drivers that you are considering before I try them in an infinite baffle in-wall setup.

I understand your desire to plan good sound into the room construction, but I might suggest more research into what makes a great sounding room instead of what makes a great sounding speaker.....

 

[Kreshna]

Moving speakers around within a room to achieve sound staging is much easier that moving walls around within the house to achieve it.

I would not use in-wall speakers as a first choice for creating a sound stage. i would consider open baffle designs for experimenting with the drivers that you are considering before I try them in an infinite baffle in-wall setup.

I understand your desire to plan good sound into the room construction, but I might suggest more research into what makes a great sounding room instead of what makes a great sounding speaker.....

Well I could go back to the original plan; building a 5 m x 3 m room to make it easier to arrange the speakers according to Cardas Golden Ratio.

What speaker model would you suggest for excellent soundstage depth, by the way?

 

[JoeESP9]

Planars are essentially open baffle speakers with very large diaphragms. IME both types typically produce an excellent soundstage.

 

[audiomagnate]

I see. So I better go with Cardas Golden Ratio instead of IB full range single driver, do I not?

What speakers are best for soundstage depth, then? I've been recently interested in Finalists loudspeakers, but do they live up the hype?

Jim: The Finalists offer the same huge atmospheric soundstage and layered depth the Statements are known for. Depending on the recording the
performers begin at the rear of the speakers and are layered to the rear and sides with the soundstage extending well beyond the width of the speakers if
recorded that way. The speakers disappear leaving only the performance. BIG sound from small speakers.

If it's true, then Finalists are what I've been looking for. Anyone experienced with the model?

I'm sure it's a very nice sounding speaker, but the claims of amazing performance are way over the top IMO. I've played around with two of the three drivers used, and the crossover is a simple 2nd order with a flipped phase mid with some mild tweaking. You literally can't get more conventional than that, it's everywhere and has been since the 1950's. As to the listening impressions, this one really stood out:
=================================================================================================================
"Dynamics:
Jim: The dynamics are exceptional with just the right amount of impact and bite to add to the realism. Not much more to say other than, I find them to sound
just right to my ears.
=================================================================================================================
Really? "Exceptional dynamics" from a conventional cone and dome 3way with an 84 dB sensitivity rating and a max output of 104 dB? Are these conventional drivers immune to the laws of physics? No thermal compression in that tweeter? Tell JBL so they can redesign their M2 monitor. Exceptional dynamics don't magically occur from conventional approaches.

Don't get me wrong, I'm positive these speakers sound great and are a much better value than conventionally distributed similar designs, but there really is nothing special about them at all, except maybe their surprisingly low sensitivity. A large amount of is sound being turned into heat by the crossover to pad down the mid and tweeter to the extraordinarily low sensitivity of the woofer. A more sensitive woofer, or maybe adding a second or third (and making it a floorstander) would definitely help.

Back to the topic at hand. OP, if you really do want an "exceptional" system, I recommend you go forward with IB 18"s on that front wall and buy a nice pair of truly dynamic floorstanders, like the JBL Studio 590 with its unique, patented, extremely dynamic HF section.

 

[Kreshna]

I'm sure it's a very nice sounding speaker, but the claims of amazing performance are way over the top IMO. I've played around with two of the three drivers used, and the crossover is a simple 2nd order with a flipped phase mid with some mild tweaking. You literally can't get more conventional than that, it's everywhere and has been since the 1950's. As to the listening impressions, this one really stood out:
=================================================================================================================
"Dynamics:
Jim: The dynamics are exceptional with just the right amount of impact and bite to add to the realism. Not much more to say other than, I find them to sound
just right to my ears.
=================================================================================================================
Really? "Exceptional dynamics" from a conventional cone and dome 3way with an 84 dB sensitivity rating and a max output of 104 dB? Are these conventional drivers immune to the laws of physics? No thermal compression in that tweeter? Tell JBL so they can redesign their M2 monitor. Exceptional dynamics don't magically occur from conventional approaches.

Indeed. .The only way to get THX levels from Jim Holtz's Finalists is by listening nearfield --1 meter or less-- and it's still one decibel short.

Don't get me wrong, I'm positive these speakers sound great and are a much better value than conventionally distributed similar designs, but there really is nothing special about them at all, except maybe their surprisingly low sensitivity. A large amount of is sound being turned into heat by the crossover to pad down the mid and tweeter to the extraordinarily low sensitivity of the woofer. A more sensitive woofer, or maybe adding a second or third (and making it a floorstander) would definitely help.

But how about soundstage depth? I noticed the PVC funnel on the back of the squawker. Perhaps such funnel has something to do in enhancing soundstage depth? Albeit artificially?

I can live with such low sensitivity, but I'd really like to experience deep soundstage --the sound that comes from behind the speakers.

Back to the topic at hand. OP, if you really do want an "exceptional" system, I recommend you go forward with IB 18"s on that front wall and buy a nice pair of truly dynamic floorstanders, like the JBL Studio 590 with its unique, patented, extremely dynamic HF section.

Well, actually there is nothing wrong with my current JBL titanium speakers; they have exceptional HF, they have pretty detailed stereo imaging (and believe it or not, the larger JBL 120Ti's have more pinpointed stereo imaging than the smaller JBL L20T's) , they have pretty wide excellent soundstage width, but alas, they don't seem to have soundstage depth.

My JBL L20T's, for example. They are used as secondary system in my garage, and the garage is pretty wide. The L20T's are about 2 meters away from each side wall, and 6 meters away from the front wall (the wall behind the speakers). And indeed, they have exceptional tonal details, stereo imaging, and soundstage width. I sometimes watch movies on my PC (which is connected to the L20T's through a Sansui A-40 integrated amplifier), and I sometimes turned my head to the left or the right, because I felt the sound come from that direction. It is almost like experiencing surround sound without surround speakers, and I'm using plain stereo.

However, the speakers still lack soundstage depth. Probably I have to accept that JBL titanium series like 120Ti's and L20T's are not designed for soundstage depth anyway. Jim Holtz's Finalists, on the other hand, aren't probably exceptional, but I wonder if the unusual design, the PVC behind the squawker, that is, would enhance soundstage depth.

Planars are essentially open baffle speakers with very large diaphragms. IME both types typically produce an excellent soundstage.

I see. Do planar speakers also produce soundstage depth as well as soundstage width?