Open baffle with Mark Audio 10P

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Hello forum,

I was thinking about buidling an OB after hearing some with fostex drivers wich sounded wonderfull (and i'm not so fond of fostex in general). I was wondering if the Mark Audio 10P driver may be a good candidate for it. I want to use it with an ported sub i'm going to build and crossover it arround 200-250hz with a passive crossover (custom build for the project off course). I do know and like Mark Audio drivers very much. I heared several designs with it and build a ported box with a 10M gen 3 wich sound wonderfull and gives more bass than i considered possible with an full range. It made me put away the tannoye reveal studiomonitors i had and liked before and sounds also way better than the high-end warfdale speakers from the 70's that my father has.

The numbers i see on the specs does not tell me that it would be a bad id, but i know those don't tell everything. Does somebody has experience with this driver in a OB, or how can you check if a driver is good in a OB.

Thanks for your help.
 
my room should be big enough (altough i did not measure it, i'm moving to a new house where this would be possibel). I guess it would be something like 10 x 8 meters and 2.5m high. I like my music on speaking level (+/- 85dB), not to loud. I do listen to bass heavy music (like reggae & dub and hiphop), but also a lot of other music (from bach to the venetian snares and from abba to zappa)

My actual Mark Audio speakers are amped with a 45w ab class stereo amp (Marantz PM5004) and hardly go over 20% of the volume of the amp (i so guess <10w or so per channel). The next room will be double the size, so i guess it won't be much more than double the wattage for the total setup.

I would like a 12dB linkwitz crossover, and got a minimalistic design ready for it as i want to keep the signal path as short as possible. Maybe i do use the natural rolloff.
 
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If your baffle is approx 20" x 20" you should get a natural roll off around 200 - 250Hz. I believe OB rolls off at 6db per octave... Can anyone confirm?

You can build a larger baffle for a little more low frequency response and use a crossover to roll the driver off where you want and at a steeper slope.

is that 20"x20" with the driver in the middle? or 20" on each side of the driver?

thanks for the info anyway. :)
 
Your room is big enough and your listening requirements reasonable enough that you could build the Martin King design: http://www.quarter-wave.com/OBs/OB_Design.pdf

Use the Mark Audio driver for the top if you like, it will work fine.

Get some distance from the back wall with the speakers: 3 ft. is good, 1.2 Meters better. Get some distance away from the speaker for listening: because of the distance between the drivers and the wide range they both cover, you will have notes
jumping from driver to driver unless you are well away from the speakers.

this design can be done with line level passive crossovers. It is nice to use
a separate amp for the bass units so one can control bass/treble balance with a remote vol. control.

Please do use open baffle for bass. It is so much more open and lively and detailed than other methods. The King design goes down to 40 hz.,plenty low in my opinion.

any questions please email me sundbyd2@gmail.com
 
NOBOX BB

Hello Waxx
Good luck with your project
This NOBOX BB is an easy way to start your open baffle journey
It can be used with a lot of different drivers and it is also easy if you want to add a tweeter or a woofer This baffle can be made out of one sheet mdf or plywood 244 x 122 mm
In fact I still use this setup every day since i started using open baffles

Succes :D
Enjoy :)
Ronny

noboxbb_ver2_tz1.gif

Fig8a-open_baffle_plans.jpg
 
Thanks you all for the info, but i will build 20hz ported woofers first anyway so OB's with woofers were not on my list. I'm already passed the planing phase and now waiting till i can move before i build them. I need those kind of woofers for my bass heavy music wich often comes near 20hz (modern experimental dub & co) so i can combine them with my ported mark audio speakers wich go low but not low enough.

I don't know if i will build also the bass in the OB's, but thanks for the info. I'll read it for sure (you never can know enough) and maybe i get convinced to build them also. As i mainly will use them for more jazz and classic music it may be good to do it anyway... When i get to them, i'll post info about the build and so, first i'll study the subject for a few months ;)
 
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Two answers (6 dB and 12 dB) were given above for the sound roll-off of an open baffle speaker.

The sound roll-off of an open baffle is 6 dB per doubling of distance and is a function of the width of the baffle. In addition a driver will have a natural second order roll-off below its resonance frequency. Hence, 6 dB per doubling of distance roll-off above resonance and 18 dB per doubling of distance below resonance.

You do need two woofers.

My Openminded open baffle project at:

http://www.diyaudio.com/forums/full...rk-audio-alpair-10-2-open-baffle-project.html

uses Mark Audio Alpair 10.2 drivers over H-frame baffles which have Eminence Kappalite 3015 LF Neo 15" woofers .

Very good open baffle sound. I used a DSP crossover network for crosssover and EQ.

Jim
 
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The beauty of DIY is that you can place your drivers where you wish on the baffle. If you subscribe to the off set theory, then go for it. But you skew your polar responses when you do this. Or you can follow Dr. Linkwitz and John K's open baffle designs and center the drivers. To each his own.

DSP can not really change those polars but it can calibrate the sound in your listening spot.
 
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