Open Baffle suggestions

irishpatrick33 · « **on:** 3 Jan 2012, 06:21 am »

Hello,
I did some research a while back about open baffle speakers and forgot nearly everything. So I am hoping people in this forum and another can refresh my memory and offer some good advice.

I do not know what type of open baffle I will build. I know I will use Wild Burro Betsys implemented as a single driver. I am tempted to build the Basic Betsy Baffle or JE labs design. It has to be a cheap design (I'm broke). My vertical limit should be 36"--certainly no higher than 42". Width can be as wide as 60". Depth to wall is about 24". I do not want to employ any notch filters or equalization--the speakers don't have to be perfect. True bass isn't absolutely necessary, as that would make common wall neighbors unhappy.

So I am wondering what I have forgotten and what has been discovered since I did the research. Could anybody advise on my baffle design options? Rules (mounting methods, orientation/location of driver, etc.)? Thanks

mcgsxr · « **Reply #1 on:** 3 Jan 2012, 12:39 pm »

There are other folks that are more science oriented than I am, and I will leave any explanations to them!

That said, I found a couple of things in building my baffles that might be helpful.

1 - For me, the ability to get slightly off axis in both horizontal and vertical helped with beaming, and presented a better image - so I would toe the baffles so that they either "cross" behind or in front of you, in terms of aiming them.

2 - offsetting the drivers horizontally provided better sound for me, so I would vary left to right where the driver is on the baffle. As I recall, the science is that by varying path length, the baffle rolls off at different frequencies in different directions, and that is desired.

3 - the JE design is a simple and good one to get you started - I suggest boring old (and cheap) mdf to build initial bafles. Once (if?) you finalize, you can move to void free marine plywood for improved sound vs mdf, but it is more expensive, so I would experiment with mdf.

4 - 24 inches off the wall is decent. More would be ideal. I would try 24 inch baffle width initially, perhaps with a slight U shape (but not more than 3-6 inches of depth) and see what you get!

scorpion · « **Reply #2 on:** 3 Jan 2012, 09:45 pm »

Here is a simu of the Betsy speaker on the Wild Burro Baffle, only I cut height to 42". One watt will hit X-max in lower bassso this will be about max SPL.
I put the Betsy center at 34" up from floor.

/Erling

irishpatrick33 · « **Reply #3 on:** 4 Jan 2012, 08:24 am »

Quote from: scorpion on 3 Jan 2012, 09:45 pm

Here is a simu of the Betsy speaker on the Wild Burro Baffle, only I cut height to 42". One watt will hit X-max in lower bassso this will be about max SPL.
I put the Betsy center at 34" up from floor.

/Erling

Thanks. Though I have no idea what the graph really means.

irishpatrick33 · « **Reply #4 on:** 4 Jan 2012, 08:57 am »

Quote from: mcgsxr on 3 Jan 2012, 12:39 pm

There are other folks that are more science oriented than I am, and I will leave any explanations to them!

That said, I found a couple of things in building my baffles that might be helpful.

1 - For me, the ability to get slightly off axis in both horizontal and vertical helped with beaming, and presented a better image - so I would toe the baffles so that they either "cross" behind or in front of you, in terms of aiming them.

2 - offsetting the drivers horizontally provided better sound for me, so I would vary left to right where the driver is on the baffle. As I recall, the science is that by varying path length, the baffle rolls off at different frequencies in different directions, and that is desired.

3 - the JE design is a simple and good one to get you started - I suggest boring old (and cheap) mdf to build initial bafles. Once (if?) you finalize, you can move to void free marine plywood for improved sound vs mdf, but it is more expensive, so I would experiment with mdf.

4 - 24 inches off the wall is decent. More would be ideal. I would try 24 inch baffle width initially, perhaps with a slight U shape (but not more than 3-6 inches of depth) and see what you get!

I'm only taking one shot at this. So no experimentation is going to occur--zero dollars and cents.

I get most of what you've said. Though I still have some questions.

What is the best performer: JE labs design, H frame, U frame, or tri-panel?

Offsetting drivers horizontally? Are you simply saying the driver should be mounted off center on the horizontal axis? It seems like you could be saying something more there.

I was under the impression bigger baffles=better. So I am a bit confused why I would choose to make a 24" wide panel when I can make it larger?

Lastly, is there a preferred method of mounting the driver. I seem to recall some say that direct coupling the driver was a bad idea.

scorpion · « **Reply #5 on:** 4 Jan 2012, 09:31 am »

To answer your confusion about my simulation. See that as a complement to Wild Burro's published frequency chart. The simu will show performance in the low end inside a room while WB's chart probably wll better estimate high frequency performance.

The graph shows like WB's what Sound Pressure Level you will get by applying 2.83 volt (=1 watt into 8 ohm) through the speaker at 1 m distance at ear level 34" . This with the speaker monted in the Basic Betsy Baffle cut to 42" height and speaker center 34" above floor.

I would build this baffle for the Betsy. I think it will be a bit better than the JE Labs which puts the speaker to low. H- and U-baffles are for bass only not broadband use.

/Erling

mcgsxr · « **Reply #6 on:** 4 Jan 2012, 01:04 pm »

I am with Scorpion on his analysis and recommendation.

Yes, all I am saying is move the driver left or right on the baffle by 2 inches or so. No magic, just simple instruction with science behind it!

If you are going to build one - if you can afford void free plywood (sometimes called marine grade) do it. If not, build it with mdf and it will still be OK.

irishpatrick33 · « **Reply #7 on:** 6 Jan 2012, 10:21 pm »

Quote from: scorpion on 4 Jan 2012, 09:31 am

To answer your confusion about my simulation. See that as a complement to Wild Burro's published frequency chart. The simu will show performance in the low end inside a room while WB's chart probably wll better estimate high frequency performance.

The graph shows like WB's what Sound Pressure Level you will get by applying 2.83 volt (=1 watt into 8 ohm) through the speaker at 1 m distance at ear level 34" . This with the speaker monted in the Basic Betsy Baffle cut to 42" height and speaker center 34" above floor.

I would build this baffle for the Betsy. I think it will be a bit better than the JE Labs which puts the speaker to low. H- and U-baffles are for bass only not broadband use.

/Erling

Thanks, that makes all the sense in the world.

I take it driver mounting method is a non-issue then?

scorpion · « **Reply #8 on:** 7 Jan 2012, 08:26 am »

If you look closely to the Betsy baffle you will see that the driver is offset from the center because the wings are of different size.
I suggested you could place the driver higher (fo better earlevel height when you listen seated) than Wild Burro Paul has done.
And also restrict baffleheight to your wished 42".

/Erling

irishpatrick33 · « **Reply #9 on:** 9 Jan 2012, 06:35 pm »

Well so much for that. Back to the drawing board.

The Betsy is sold out. Do I have any other driver options that are near the price range without compromising performance? Thanks

closeyoreyesandlisten · « **Reply #10 on:** 9 Jan 2012, 07:43 pm »

New to this site and am really interested in investigating the open baffle concept:

Since I'm on a very limited budget - I am going to pull some drivers out of the cabinet I have them in, and experiment with a pair of Peak/Coral 8" Coax's I have into an open baffle; if you're game for it: either experiment with a pair of drivers you already have, or look to the resale market at less expensive drivers than the ones you're considering buying.

Present System: Marantz 8001 CD, or Sanyo PLUS 35T Tuner, into Stromberg-Carlson ASP-422 Power Amp with attenuators as volume controls; sound comes out either University Master Series M6 3-way in origional 1956 cabinets or Peak/Coral 8CX-501 Coax recycled into Watterson bookshelf cabinets; SilNote Audio interconnects and Radio Shack 14g flatwire speaker cable.

Looking forward to hearing thoughts of others... Good Luck to you and Best Wishes in this New Year.

scorpion · « **Reply #11 on:** 9 Jan 2012, 07:47 pm »

Actually you could go with the Betsy-K and try to apply some small bass boost. The difference to Betsy will not be really more than marginal.

You might try the SICA 10D 1.5 CS, which seems to be available for about the same money in Europe. Use the Betsy baffle only adjust the speaker baffle width to house a 10"er.

/Erling

irishpatrick33 · « **Reply #12 on:** 11 Jan 2012, 12:40 am »

Quote from: scorpion on 9 Jan 2012, 07:47 pm

You might try the SICA 10D 1.5 CS, which seems to be available for about the same money in Europe.
/Erling

There seems to be a sizable difference in the resonance frequency. Will I be giving away bass by choosing the Sica?

scorpion · « **Reply #13 on:** 11 Jan 2012, 10:08 am »

Not at all. The SICA will average about 95 dB in the low bass in reference to the figures above. It will be down to 90 dB at 60 Hz just like the Betsy. The little higher Qts value of the SICA will compensate for the difference in Fs.

/Erling

matevana · « **Reply #14 on:** 11 Jan 2012, 02:02 pm »

Always wanted to try these. You can find them for around 50 bucks a pop.

http://www.eminence.com/speakers/speaker-detail/?model=Beta_12LTA

mcgsxr · « **Reply #15 on:** 11 Jan 2012, 02:49 pm »

QTS of 0.5, FS of 45Hz, and 97db efficiency. I suspect those Eminence could work on OB for sure. Limited XMAX (typical of pro woofers), but with responsible use of the gain, they should do just fine.

irishpatrick33 · « **Reply #16 on:** 16 Jan 2012, 06:59 pm »

Man, buying that Sica 10D 1.5 CS is nearly impossible. The only distributor I can find is teamdaudio.fr

They won't take paypal. I am not comfortable using my credit card overseas either.The only other option is to wire money and pay $45 to do so.

Is there any other options that are accessible within the USA? I am willing to spend a bit more money. Thanks

mcgsxr · « **Reply #17 on:** 16 Jan 2012, 08:08 pm »

If (and it is a big if) the Sica is also branded by Jensen, Solen in Canada stocks some of their drivers. I have dealt with Solen numerous times, and always been happy, but then again I am in Canada too!

I don't see the 10D 1.5 CS, but perhaps reach out to them and ask?

http://www.solen.ca/pub/cms_nf_catalogue.php?man=56

scorpion · « **Reply #18 on:** 16 Jan 2012, 08:28 pm »

Hi Patrick,

Judging from your Profile Local Time I thought you were in Ireland.
The French firm, one Swedish Firm and Breitbandlautsprecher of Bremen Germany have the SICA Fullranger.
The Frenchmen, TeamAudio.fr do take Paypal, at least they say so in french under the Payment entrance on the Shopping Cart page.

/Erling

irishpatrick33 · « **Reply #19 on:** 16 Jan 2012, 11:21 pm »

I also thought teamaudio.fr accepted paypal. But that option is only reserved for the cool European types.

I have contacted Solen already. No response as of yet.

Scorpion, I assume the German outfit you are referring to is http://www.spectrumaudio.de/. Not sure who the Swedish one is.

I am to the point where I wonder if Seas or another brand that can be purchased locally is worth the price increase.