[stlblue]

I found the interchangable top plate idea: http://www.websiteonline.net/b200/b200.htm# (includes a cool 20 sec video at the bottom).

Does anyone think hinges are a bad idea? I was thinking that the front baffle could be 18" wide, w/ two 9" wings that fold out during use and could serve as protection to cover the driver when not in use by folding it closed. It might also look better in the room when not being used. 

[mcgsxr]

There will be some who may suggest that wings are bad, as they might be a cause for concern around "flapping".

I have been using wings on my baffles, with piano hinges, for around 3 years now.  For 95% of the time it is fine, and awesome for fine adjustments.  The other 5% of the time (typically when I am working with very bass filled material) there can be some resonance that sets up IN the hinges.  I have not bothered to damp this, as it does not happen often.

I would imagine that some tape, or inner tube could be used as a "hinge" of a sort, for experimentation for angle etc.

[TerryO]

Thanks for the quick replies, guys. A couple more questions, please. Do you think the depth of the legs could add more bass? The Yamamoto's seem to have almost no depth to their legs, versus the 5" & 10" depth from these plans:



Also, the top "plate" measures 8" wide, but do you think that is mostly for 8" drivers and 15" wide plate might be better for the 604's?

Mr. Blue, 

After reading this thread I'm not sure if your question on the JE Labs baffles has been completely answered.

Yes, the wings add bass, however if they are close to the woofer they can cause a "Tunnel" effect which does to a certain extent change the loading on the back of the woofer. The JE baffle is wide enough with the "wings" being a fair distance from the driver that this shouldn't be a great concern.

In regards to that 8 inch *tab* at the top of the baffle, several people actually placed a full width piece that bridges the top and is affixed to both of the side wings. It's structurally better and it would give an increase in bass. The fun is to experiment for yourself and draw your own conclusions. Personally, I go through a lot of cardboard, but I heat my place with a wood stove so all my mistakes also have a positive spin.

Here's a couple of things to consider:
Place your bass driver as low or as close to the floor as feasible, say 4-5 inches, from the bottom of the baffle to the bottom of your bass driver. It improves the bass and more importantly, the coherency of the bass as the arrival times from your driver and the reflected sound from the floor will be pretty much in phase.

The down side is, if you're using a single driver (and in your application it amounts to the same thing), many people don't care for the sound coming "up" to them from near the floor. If you were to use a second, bass-only woofer to help sustain a fuller bass line on your open baffle, then placing your driver above the dedicated woofer would be better.

You may already be aware of the baffle roll off that takes place when the out of phase front and rear sound waves meet and cancel each other. It's entirely dependant on frequency (wave length). When the longer wave lengths exceed the total width of the baffle (included are the wings) the cancellation, in theory, equals 6 dB. Please note however, that the baffle width (or distance from front to back) is actually the average of all points from your driver to the "edges" of the entire baffle. So unless your driver were placed in the exact middle of a perfectly circular baffle and suspended in the air the rolloff slope is not nearly the "Sudden 6" predicted by theory. The floor presents a mirror image for bass reinforcement and the slope can actually be fairly gentle given the size and shape of the JE Labs baffle.

As a lot of this seemed absent in this thread, I hope this clarifies some of the mystery "surrounding" OB's.

Best Regards,
TerryO

[stlblue]

I haven't built these yet, but plan to fairly soon. One concern is they would eventually be used in a living room w/ a dining room directly off the side, at the speaker end, forming the dreaded "L." Will this cause troubles for the OB's that should make me consider "boxes" instead?

[TerryO]

I haven't built these yet, but plan to fairly soon. One concern is they would eventually be used in a living room w/ a dining room directly off the side, at the speaker end, forming the dreaded "L." Will this cause troubles for the OB's that should make me consider "boxes" instead?

Mr. Blue,

I'd encourage you to use some cheap MDF or A/C plywood and just try it out. It's really hard to predict what the outcome may be in advance. Is there any reason why you can't use the corner opposite the Dining room and place the baffles on either side of the corner facing out? This actually works well, but OTOH, the very strength of OB's is their ability to create cancellation nodes parallel to the baffle, so that open area to one side may not be as big a problem as you might have with a more conventional enclosure.

Best Regards,
TerryO

[gortnipper]

Place your bass driver as low or as close to the floor as feasible, say 4-5 inches, from the bottom of the baffle to the bottom of your bass driver. It improves the bass and more importantly, the coherency of the bass as the arrival times from your driver and the reflected sound from the floor will be pretty much in phase.

Terry - how much of a bass improvement would be seen on a heavy shag carpet over concrete floor placing the drivers so low? I would think that the reflected sound in this scenario would be fairly low, and so would the perceived coherency?

David

[panomaniac]

The JE Labs baffle is nice, but I just don't see how you will get enough low end out of the 604.
A low Qts, low Fs driver like that is going to be pretty bass shy on OB, isn't it?   Or will you use a lot of EQ?

[kyrill]

hi
forgive me for "riding" on this thread as i am also making my first OB adventure

I hope my question will be valid for Stlblue as well

the side panels but not really at the side as the photoos show is a kind of "U-frame" no?
by adding a Uframe  you enlarge in a sense the baffle and so lower the bass. Making the
side baffles to large you may introduce a tunnel effect when panels are too close to the drivers
But what happens when you  dont make the panels parallel to each other but angled, say between 60 and 80 degrees (or 100-120 degrees depending on how you look at it)  respectively to the front baffle?

Personally ( taste) i find square baffles very ugly, so a "hidden " U frame   can make the baffle more  rectangle-looking

[TerryO]

Place your bass driver as low or as close to the floor as feasible, say 4-5 inches, from the bottom of the baffle to the bottom of your bass driver. It improves the bass and more importantly, the coherency of the bass as the arrival times from your driver and the reflected sound from the floor will be pretty much in phase.

Terry - how much of a bass improvement would be seen on a heavy shag carpet over concrete floor placing the drivers so low? I would think that the reflected sound in this scenario would be fairly low, and so would the perceived coherency?

David

David,
The shag rug wouldn't necessarily detract from the sound, but unless your room is pretty "live" it may not have any effect at all. Bass frequencies are the least likely to be attenuated by the carpet, it does attenuate, to an extent, higher frequencies that can cause phase cancellation or combinations due to the reflected vs. direct sound. Most effective room treatments are addressing this situation, as the bass eigenmodes are harder to treat because they are influenced by room volume, the dimensions and the ratios of the H,W& L of the room itself. Placement of the speakers within the room and the position of the listener can be adjusted to mitigate the effects upon the perceived sound.
If you've had other speakers in the room before and have been happy with the sound, I doubt that too much would change via-a-vis the bass.

The thing is to experiment and adjust until you're happy, it's fun to do and it keeps you out of the Taverns

Best Regards,
TerryO

[stlblue]

hi
forgive me for "riding" on this thread as i am also making my first OB adventure

I hope my question will be valid for Stlblue as well

the side panels but not really at the side as the photoos show is a kind of "U-frame" no?
by adding a Uframe  you enlarge in a sense the baffle and so lower the bass. Making the
side baffles to large you may introduce a tunnel effect when panels are too close to the drivers
But what happens when you  dont make the panels parallel to each other but angled, say between 60 and 80 degrees (or 100-120 degrees depending on how you look at it)  respectively to the front baffle?

Personally ( taste) i find square baffles very ugly, so a "hidden " U frame   can make the baffle more  rectangle-looking

Good question, kyrill. I know the top plate should be parallel to the ground, but could (should?) the legs be angled? Also, it was mentioned that the top plate running across the full length of the baffle would add structural strength. What would be the effect of running a plate the full length of the bottom, from leg-to-leg? Would this give the added strength, while still giving the flexibility of the top plate being as needed?

[opnly bafld]

deleted

[JoshK]

How much are the 604's?  I forget.  I had inquired once.  There is an interesting thread on AA about the 604 vs. Tannoy westminsters.   In it another driver of interest to the coax fan crowd was mentioned.  Its an RCF CX15N315.  It looks intriguing too.

[chrismercurio]

$685 each no crossover
$750 w/ crosover

[chrismercurio]

The JE Labs baffle is nice, but I just don't see how you will get enough low end out of the 604.
A low Qts, low Fs driver like that is going to be pretty bass shy on OB, isn't it?   Or will you use a lot of EQ?

I think it depends on what you want. I haven't seen ANY measurements from anyone, but reports from the field indicate an f3 around 70hz. It is a wide baffle...and stereo subs can always be used to support the low end.

Chris

[panomaniac]

It is a wide baffle...and stereo subs can always be used to support the low end.

The Je Labs - Warfdale baffle is.  But the OP said 18" wide.  That means 16x18" - so that means F3 about an octave up.
(Hypotenuse of 47.5" vs 24")
The 35.5x 31.5 low baffle "may" give you usable bass - that's a lot of surface area - but with a low Qts / low Fs driver like the Altec, I'd have to hear it to believe it.

The higher Q / higher Fs Alpha 15 is popular because it does not need much EQ on a medium to large baffle.

I still think some kind of EQ is going to be needed for the 604 on OB to achieve a good tonal balance.

[gooberdude]

At  $750 per driver w/x-over....why not just go with Hawthorne's Sterling system?

Its designed for OB, no guesswork, and there aren't issues with the top end frequencies due to the Radian tweet.


sorry to schill!!!!     I just spent about $1500 in OB drivers recently and I'm a bit biased     

[TerryO]

The JE Labs baffle is nice, but I just don't see how you will get enough low end out of the 604.
A low Qts, low Fs driver like that is going to be pretty bass shy on OB, isn't it?   Or will you use a lot of EQ?

I think it depends on what you want. I haven't seen ANY measurements from anyone, but reports from the field indicate an f3 around 70hz. It is a wide baffle...and stereo subs can always be used to support the low end.

Chris

Chris,
If they go to 70Hz, I think that would be pretty good and, as you mention, a subwoofer could take over from there. Just about every OB I've seen, with the exception of the Carver Amazing Speaker, needs to have a subwoofer if really deep bass is expected. I don't know how many here went to VSAC, or saw the reports on it a couple of months ago, but the Lowther America room featured a Lowther/Tone Tubby OB speaker that was just wonderful. It crossed to the Tone Tubby at 200Hz with a 1st order crossover. They did have a sub, comprised of a Hartley woofer (18 or 24 inch?) for the deepest bass. A really nice setup with a solid Maple baffle about 20 inches wide and short wings in back.

Here's some VSAC coverage:

http://www.audiocircle.com/index.php?topic=54959.msg491672;topicseen

http://www.6moons.com/industryfeatures/vsac20082/vsac.html

I haven't checked but one or the other probably has a picture of the Lowther America OB.

Best Regards,
TerryO

[chrismercurio]

I already bought the subs and will know how well it all works in a couple of months....

[TerryO]

I already bought the subs and will know how well it all works in a couple of months....

What are you going to have for subs? Are you building your own enclosures or is it a package deal?

Best Regards,
TerryO

[stlblue]

The JE Labs baffle is nice, but I just don't see how you will get enough low end out of the 604.
A low Qts, low Fs driver like that is going to be pretty bass shy on OB, isn't it?   Or will you use a lot of EQ?

I think it depends on what you want. I haven't seen ANY measurements from anyone, but reports from the field indicate an f3 around 70hz. It is a wide baffle...and stereo subs can always be used to support the low end.

Chris

Chris,
If they go to 70Hz, I think that would be pretty good and, as you mention, a subwoofer could take over from there. Just about every OB I've seen, with the exception of the Carver Amazing Speaker, needs to have a subwoofer if really deep bass is expected. I don't know how many here went to VSAC, or saw the reports on it a couple of months ago, but the Lowther America room featured a Lowther/Tone Tubby OB speaker that was just wonderful. It crossed to the Tone Tubby at 200Hz with a 1st order crossover. They did have a sub, comprised of a Hartley woofer (18 or 24 inch?) for the deepest bass. A really nice setup with a solid Maple baffle about 20 inches wide and short wings in back.

Here's some VSAC coverage:

http://www.audiocircle.com/index.php?topic=54959.msg491672;topicseen

http://www.6moons.com/industryfeatures/vsac20082/vsac.html

I haven't checked but one or the other probably has a picture of the Lowther America OB.

Best Regards,
TerryO

So if I don't want to deal w/ a sub, "boxes" may be the way to go?