[jonirvine]

I have a pair of Dayton PS180's and a PS220 I'm using in an OB setup.  I was wondering if there is any benefit of rear mounting them and chamfering out the hole as sort of a wave guide?  I realize it wouldn't be much of a wave guide but are there any pros/cons to this design?  They're pretty small baffles, roughly 8" x 12" for the 180's and 34" x 11" for the 220

[JohnR]

I've not tried it but I can't see any advantage to it....

[lowtech]

Read about the advantages here: http://linkwitzlab.com/m_panel.htm.  Specifically list item "J".

[Æ]

I have a pair of Dayton PS180's and a PS220 I'm using in an OB setup.  I was wondering if there is any benefit of rear mounting them and chamfering out the hole as sort of a wave guide?  I realize it wouldn't be much of a wave guide but are there any pros/cons to this design?  They're pretty small baffles, roughly 8" x 12" for the 180's and 34" x 11" for the 220

More cons than pros, especially for full range drivers.

A little chamfering or a roundover to the driver mounting hole won't make it into a "waveguide."
Diffraction off the face, front of the baffle is never good, especially when you are up into the midrange and treble frequencies. Flush mounting is usually considered to be the ideal and can be confirmed by microphone measurements.

Now that bit over at Linkwitz's website of supporting a woofer by the magnet is an excellent idea, and can still be achieved with a conventional front mounted woofer. Linkwitz isn't using full rangers, he is using woofers. With the long bass wavelengths you don't have to worry about a little bit of diffraction.

[lowtech]

Not sure I'd say there are more cons than pros for rear magnet/compression mounting a full range driver.  However, some of the "cons", such as the diffraction issue you mentioned, can be mitigated by increasing the depth of the rabbit joint so that there is not much material between the front of the basket and the front of the baffle. 

Another alternative is to magnet mount the driver in a similar way to how SL mounts the midrange driver in the Orion.  That method introduces added construction complexity but can achieve similar results in reduction of baffle related resonances.

I'd recommend the OP read some of the topics covered here: http://linkwitzlab.com/frontiers_2.htm#N

P.S.  I often cringe when folks create 2" thick baffles for their "open baffle" projects.  While creating a thick baffle will minimize panel resonance, it will also introduce other problems like cavity resonances and will affect the polar pattern to a degree where their driver(s) no longer behave like a dipole.

[Æ]

Not sure I'd say there are more cons than pros for rear magnet/compression mounting a full range driver.  However, some of the "cons", such as the diffraction issue you mentioned, can be mitigated by increasing the depth of the rabbit joint so that there is not much material between the front of the basket and the front of the baffle. 

Another alternative is to magnet mount the driver in a similar way to how SL mounts the midrange driver in the Orion.  That method introduces added construction complexity but can achieve similar results in reduction of baffle related resonances.

I'd recommend the OP read some of the topics covered here: http://linkwitzlab.com/frontiers_2.htm#N

P.S.  I often cringe when folks create 2" thick baffles for their "open baffle" projects.  While creating a thick baffle will minimize panel resonance, it will also introduce other problems like cavity resonances and will affect the polar pattern to a degree where their driver(s) no longer behave like a dipole.

Mr. Linkwitz isn't using "full range" drivers.
The end (hopefully).

[lowtech]

Mr. Linkwitz isn't using "full range" drivers.

Thank's for clearing that up. 

[Æ]

Thank's for clearing that up.

I'd like to know how many times you've actually met and talked with Mr. Linkwitz and/or listened to his Orions?
My answer to that question is twice.

[lowtech]

I'd like to know how many times you've actually met and talked with Mr. Linkwitz and/or listened to his Orions?
My answer to that question is twice.

Good for you. 

Aside from hosting a GTG at my home with Mr. Linkwitz and having built two pairs of Orions and living with them for four years, none.

Any other questions?   

[Æ]

Any other questions?

Yes, I have at least two more questions.

Did you just happen to notice that the tweeter and midrange are flush mounted from the front and not rear mounted?

They say a picture is worth a thousand words, need I say more?

[jonirvine]

lol... thanks for the help... I guess I'll refrain from rear-mounting. 

[matevana]

I have a pair of Dayton PS180's and a PS220 I'm using in an OB setup.  I was wondering if there is any benefit of rear mounting them and chamfering out the hole as sort of a wave guide?  I realize it wouldn't be much of a wave guide but are there any pros/cons to this design?  They're pretty small baffles, roughly 8" x 12" for the 180's and 34" x 11" for the 220

Hey Jon,

I played around with it in a full range design and can't really claim any sonic benefits. Aesthetically though, it looks pretty cool... especially when the drivers are rear mounted and there are no screw heads visible on the front side of the baffle. You can also cut a rubber mounting gasket from thick plumber's gasketing material when you face mount the driver which may lessen the overall system's moving mass. 

[lowtech]

Did you just happen to notice that the tweeter and midrange are flush mounted from the front and not rear mounted?

They say a picture is worth a thousand words...

Did you happen to *read* my initial reply in this thread?

"Another alternative is to magnet mount the driver in a similar way to how SL mounts the midrange driver in the Orion.  That method introduces added construction complexity but can achieve similar results in reduction of baffle related resonances."

And, did you happen to notice that the pic you posted of the Orion baffle is missing screw holes for the midrange driver?  The part missing from your pic is the mounting bracket that completely decouples the driver from the baffle.



"The rim of the driver is not screwed to the front baffle. Instead, it floats mechanically and the narrow gap between it and the baffle is sealed with a soft foam strip. No forces are transmitted between driver rim and baffle. The speakers look the same from the front as before, except that there are no screws.

What is the sonic benefit? Well, it does not jump out as something you immediately point to. As I go through my selection of familiar material it becomes clear that human voice, soprano, stringed instruments and many other sounds have assumed a degree of naturalness that surpasses what the ORION was capable of before (it was magnet mounted). I find that I play many recordings at even higher volume level and thoroughly enjoy the richness and subtleties of their sonic fabric and dynamism."

http://www.linkwitzlab.com/orion-rev1.htm

need I say more?

Let's hope not.   

[Æ]

Did you happen to *read* my initial reply in this thread?

Oh yeah, another question for you. Why should I read your replies, it's not your thread?
My opinions are intended soley for the benefit of the OP.
By the way, "floating" drivers has been around for a long time, a very long time.
I'm glad you enjoyed my replies, see you on the backside.

[jonirvine]

Aesthetically though, it looks pretty cool... especially when the drivers are rear mounted and there are no screw heads visible on the front side of the baffle.

Ha, well being a designer by trade, I must admit aesthetics are pretty high on my priority list!  However, after listening/reading this http://www.youtube.com/watch?v=VC-sxvNzC8I&feature=BFa&list=PL62CE612D23703C3B&lf=results_main and http://www.linkwitzlab.com/AES-London'07/AESUK_lecture_0711.pdf today, I'm learning to err on the side of function more than form.  It's tough for me to do but I'm learning.

P.S. Thanks Æ and lowtech for your advice, I'm learning a ton just listening to you two go back a forth! 

[lowtech]

Oh yeah, another question for you. Why should I read your replies, it's not your thread?

Um... because you *are* responding to my replies?  It's probably worthwhile reading them, no?

My opinions are intended soley for the benefit of the OP.

You sure seem a touch defensive if that's truly the case.   

By the way, "floating" drivers has been around for a long time, a very long time.

Thanks again for pointing out the obvious.  No pictures this time?   

Jon - Good luck with your design.  You will find that the driver mounting is a very small detail compared to the overall shaping you do to the response curve.

[planet10]

Mounting the drivers from behind is a choice. Implemented well there are few drawbacks.  Magico & Pass are 2 examples of hi-end speakers that use this technique.

I am working on a statement FAST... the mid=tweeters will be rear-mounted -- in this case on a 4-5mm aluminum sub-baffle. There will be a 45 degree (or greater) champher on the front.

dave

[chrisby]

Ha, well being a designer by trade, I must admit aesthetics are pretty high on my priority list!  However, after listening/reading this http://www.youtube.com/watch?v=VC-sxvNzC8I&feature=BFa&list=PL62CE612D23703C3B&lf=results_main and http://www.linkwitzlab.com/AES-London'07/AESUK_lecture_0711.pdf today, I'm learning to err on the side of function more than form.  It's tough for me to do but I'm learning.

P.S. Thanks Æ and lowtech for your advice, I'm learning a ton just listening to you two go back a forth! 

most notably from the current exchange are the finer points of forum etiquette, diplomacy, and through this post, passive aggressive self approbation 

[lowtech]

No comment.

[chrisby]

No comment.

"no comment"  is a comment 

oh, I see - irony   

don't we all sometimes take ourselves a bit too seriously?