Seas Excel W22's in open baffle, need more midbass "oomph"

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I've been experimenting with open baffle for quite some time now, first with two Seas Excel W22's mated with a Vifa XT25 tweeter per channel. Midrange was severely lacking so I added a Seas Excel W15CY per side to play 300hz-2250hz. Now it sounds incredible but I am seriously lacking in the midbass region. The W22's play 120hz-300hz while six Acoustic Elegance OB15's play everything below 120hz. I have experimented with going as high as 150hz with the AE 15's and may just try crossing over at 300hz to cut out the W22's all together. But I would like to avoid this, I have a soft spot for the W22's :) Is anyone boosting the lower end of the W22's with eq to compensate for the missing midbass?

I have read Linkwitz' Orion build documentation and I do not remember him doing anything special with the W22 low end, though it has been about a year since I've reviewed those notes. I was also thinking about sealing them to help with output. I have been playing around with REW and my MiniDSP but it does not really show any deficit in the W22's coverage, perhaps I need to look for more REW tutorials or my hearing is skewed. Would love to hear the ramblings of my fellow DIY'ers who have used W22 Excels in an open baffle. Thanks!
 
Hello architect,

in my AINO dipoe project I noticed that the output of 12" beyma dips very rapidly below 150Hz (frameless dipole). I tried to eq the low end (the driver can do that easily) but because the crossover slopes have "legs" this is not enough! I ended up with xo at 300Hz,then slopes are "normal" and the sound is a lot better.
 

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Hello architect,

in my AINO dipoe project I noticed that the output of 12" beyma dips very rapidly below 150Hz (frameless dipole). I tried to eq the low end (the driver can do that easily) but because the crossover slopes have "legs" this is not enough! I ended up with xo at 300Hz,then slopes are "normal" and the sound is a lot better.

Thanks for the reply, what slope are you using? I'm using 48db/octave with my miniDSP.

What are your baffle dimensions for the W22 ?

10" wide, here is a pic for reference:
JEJftFA.jpg
 
Hey glad you stopped by, I am a huge fan of your site! I actually got the Monacor waveguide idea from you. Do you prefer the SEAS DXT over the XT25/WG300?

Thanks :)

Yes I prefer the DXT, but much of it is because subjectively I like metal domes. The DXT has no phase shield and a waveguide as bonus !

XT25 do sound sublime in the higher frequencies, but it (and other textile dome tweeters) can't match the resolution of DXT (e.g cymbal sounds). But as you know metal domes can sound a bit harsh given the "correct" material.
 
Open Baffle 8 inch Seas

Hi Architect,

Congratulations, nice system!

I also really like the 8 inch Seas Excel W22 driver in open baffle.
I got great results with a Variable Path Length ( sadly VPL !) which added slam, depth, texture, detail, extension....You name it if its good you got it with the extended side cheeks with " Shark Bites" taken out of them.

Basically you get all of the advantages of an extended rear H frame with none of the disadvantages ie all tghe good stuff above without any cuppy male vocals and muddy bass.
The " Angels " pictured in Acrylic and Corian were only 365mm wide but the 500mm to 220mm variable depth gave an average effective baffle width of nearly 1 meter. They went all the way down to 34 Hz, flat, and sounded really great.
The last pic was a Volt 2500.4 in a small VPL baffle, from 100Hz to 500 Hz...Wow!

Hope this helps and all the best
Derek.


PS Just a suggestion, how about 4 W22 per side in a VPL open baffle and crossover at 50Hz to your big AE drivers...You might even find you dont need the big AE drivers anymore and can sell them, pocket some cash and save space in your room? Just a thought!
 

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architect7,
if I can look right at the scale in the picture, my slopes are close to LR2 (12db/octave) acoustically.

I am using minidsp, the software (electrical) slopes are far from these, because dipole transducers have -6db/oct attenuation in the low end of range. HP slopes in minidsp can be 6dB/oct for dipoles!

Some other people have noticed that mild slopes work better, the transition from a driver to another is "softer", which helps to get dispersion changes softer too. And yes, you can kind of hear that.

You must check for phase too for each xo! Invert phase and run test, adjust delay. Also please measure at 30¤ and 60¤ angles too! I have used 30¤ for reference standard.

See my post #162 http://www.diyaudio.com/forums/multi-way/231353-aino-gradient-collaborative-speaker-project-17.html and so on! the xo at post #162 is not final, I made slopes even less steep, post #165

I love minidsp!
 
Just raise the crossover to 150 or so. I use the IB15 in an H baffle with my dipole tops and just 110 to 130hz makes a big difference in "slam" and effortlessness even when playing at the same soundlevel. Btw the Orion has imho close to zero impact in the midbass even if the numbers indicate otherwise, membranarea is the key. Earlier I used two w22s in Phoenixbaffles and that was somewhat better but no IB15. :)

You dont have to play loud to appreciate area!
 
As an appendix to message #11,

When I gave up of looking at minidsp "curves" of xo, I set the xo-frexquencies unsymmetrically too!

Linkwitz and Riley are wise guys and mathematicians! The LR slopes work very well acoustically, conserving energy and phase.

Architect7 - do you have a measuring microphone (a good net camera will do, I have used MS LifeCam 3000HD with success) and some analyzer program? I use REW, ARTA and Holmimpulse are very good too but a little more "tecnical". Without you will never get "there"
 
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Looking at your picture of the system, my first impression is that the baffle is not wide enough for running the W22 any lower than 200 Hz.

It's of course possible to EQ as much as you like in the low end, but it will result in high distortion levels and will not sound good.
 
Volt in VPL

Hi Toaster,

Thanks, glad you like the asthetics, I think speakers need to look good as we spend a lot of time with them...Just like wives really!!

The Volt BM 251.3 is a slightly more sensitive version of the BM2500.4 ( where does he get those model numbers from?) with a higher Fs.
It should still sound great in a VPL style open baffle.
It all depends on the size of baffle / depth of the side cheeks but you can get good response down to around 100Hz with no Eq and a similar size of baffle to the attached.
You can then add some Eq but I advise caution ie not more than around 5dB to 6dB boost at around 70Hz to 80Hz as you will run out of Xmax quickly.
The real advantage of this VPL is that it gives you lightening fast transiets and super clean low midrange, this VPL and Volt combo is not designed to do bass.
I'll post a couple of other pics of a 15 inch Beyma and Precision Devices for sub 100Hz.

Hope this helps and all the best
Derek.
 

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VPL bass

Here are some pics of a VPL bass system using two 15 inch pro drivers, a Beyma 115K and a Presision Devices 158 bass mid.
I run the Beyma from 80Hz to 25 Hz with some Eq boost and the Precision Devices from 80Hz to 400Hz then the Manger driver up to 20KHz.

The cabinets were light weight, only 18mm MDF, but the big drivers were not bolted to the cabinets and they did not actually touch the cabinets. I suspended the drivers ( not very pretty, but it was later covered with grill foam) using soft polyprop cord and used 10mm thick sorbothane gaskets around the drivers front and rear edges ( the driver were rear mounted) and small beech wood blocks to guide the drivers into place.

The Manger was also suspended and also ran open baffle, later used a giant horn to add about 6dB sensitivity to the Manger.

Even at very high SPL there was no cabinet vibration...really great way to go.

Cheers
D.
 

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