Thoughts on Open Baffle Subs

[davelittel]

I have a new large/open living room and I'm thinking about building in two "architectural" subs. My idea is to open the bottom of each box to the crawl space below the house. The crawl space is large and pretty well protected from weather. The subs would thus be operating as open baffle at least in the sense that the back wave would radiate into space outside the house. I'm thinking about either high end 15" Dayton subs or a pair of Rythmik Audio 15" subs with their dedicated amps. I believe Rythmik can sell you a version of their amps that are optimized for open baffle

I'm assuming I would have to incorporate some form of EQ to get the responses right. The advantages are 1) smaller box required in the room and 2) potential sound quality improvement over a boxed sub.

#2 is what I want to ask about. In reading over the years I occasionally see claims that an open baffle sub can offer the most uncolored bass. Is this true? I'd be interested in any thoughts on this, or the practicality of a system like this open to a crawl space. Thanks in advance.

[jonasz]

Re: Thoughts on Open Baffle Subs

What your describing would be called an IB Infinate Baffle sub, and yes, they're awesome!

[Adam_G]

Re: Thoughts on Open Baffle Subs

As said above, what you're describing is known as an "Infinite Baffle" subwoofer. There are certain things you need to look for in these subwoofers, which someone more knowledgeable will fill-in here later (I hope!). Parts Express sells a subwoofer designed for just such an installation, the IB385-8 15" IB Subwoofer..

[lennon_68]

Re: Thoughts on Open Baffle Subs

+1 for IB being awesome. Things that come to mind:

- With IB displacement per $ is key
- With an adequately sized IB (such as yours) the system Q = the driver Q
- Big beefy drivers aren't required, there is no enclosure so the drivers don't need to be able to handle a lot of power (you'll reach the mechanical limits of the suspension way before reaching the thermal limits of the driver).

The above 3 notes are reasons that IB specific drivers are made. They're generally designed with a Q close to .707 and can be made with smaller motors than is generally used on similar sized drivers.

[jonasz]

Re: Thoughts on Open Baffle Subs

These would be great for the purpose.

http://aespeakers.com/aes_store/catalog/product_info.php?cPath=30&products_id=104

[evilskillit]

Re: Thoughts on Open Baffle Subs

These would be great for the purpose.

http://aespeakers.com/aes_store/catalog/product_info.php?cPath=30&products_id=104

[ATTACH=CONFIG]54251[/ATTACH]

As would these hehe: http://store.ficaraudio.com/ib318/

But for the money I don't think you can get more swept displacement right now for less than the Stero Integrity 18" drivers for $160 shipped right now. And with IB once you add EQ into the equation displacement is about all that matters.

http://techtalk.parts-express.com/showthread.php?245888-Stereo-Integrity-HT18-159-99-shipped-til-end-of-month

[donradick]

Re: Thoughts on Open Baffle Subs

@davelittel

I have no experience with either building or listening to IB subs, but I've noticed that everyone that has, is not going back a box.
Here's some further resources:
http://ibsubwoofers.proboards.com/

http://home.comcast.net/~infinitelybaffled/

Hope this helps.

[rmeinke]

Re: Thoughts on Open Baffle Subs

@davelittel

I have no experience with either building or listening to IB subs, but I've noticed that everyone that has, is not going back a box.
Here's some further resources:
http://ibsubwoofers.proboards.com/

http://home.comcast.net/~infinitelybaffled/

Hope this helps.

+100

I have not done an IB but have OB bass bins and will NEVER go back to a box. After listening to my open baffles, I went back to my boxed speakers and could NOT BELIEVE HOW MUFFLED AND [email protected] they sounded. I really loved them before the OB's but once you listen to them compared to OB its game over for the box!!!

[Face]

Re: Thoughts on Open Baffle Subs

As would these hehe: http://store.ficaraudio.com/ib318/

But for the money I don't think you can get more swept displacement right now for less than the Stero Integrity 18" drivers for $160 shipped right now. And with IB once you add EQ into the equation displacement is about all that matters.
http://techtalk.parts-express.com/sh...l-end-of-month

The FI and AE woofers are excellent choices, if not the best. The SI driver is not optimal for IB. If you want something cheaper, pick up Dayton's IB driver.

[evilskillit]

Re: Thoughts on Open Baffle Subs

The FI and AE woofers are excellent choices, if not the best. The SI driver is not optimal for IB. If you want something cheaper, pick up Dayton's IB driver.

Care to explain why the Dayton IB15 would be superior to the SI 18" woofer to me? I could model the two and look at the graphs but I'm at work right now. I'm guessing with EQ there's nothing that'd be better about the IB15 if using the same number of drivers. Not trying to be obnoxious, I'm actually curious.

[JRT]

Re: Thoughts on Open Baffle Subs

I have a new large/open living room and I'm thinking about building in two "architectural" subs. My idea is to open the bottom of each box to the crawl space below the house...
.

For each subwoofer, you can place a manifold box inside of the crawl space with a vent through the floor, with a woofer (or woofers) mounted to the wall(s) of the manifold box.

If you have a rectangular room, four of these would be optimal, located as shown below, explained in the Harman whitepaper at the link further below. The pic shows four woofers in each manifold. Regardless how many you use, the woofers are wired such that they all push air into the room in unison as they excurse.



http://www.harman.com/EN-US/OurCompa...s/multsubs.pdf

[Face]

Re: Thoughts on Open Baffle Subs

Care to explain why the Dayton IB15 would be superior to the SI 18" woofer to me? I could model the two and look at the graphs but I'm at work right now. I'm guessing with EQ there's nothing that'd be better about the IB15 if using the same number of drivers. Not trying to be obnoxious, I'm actually curious.

With EQ, the differences will be that the Dayton has a friendlier impedance for multiples, it's cheaper(much more when including shipping), but the SI will have more headroom. http://i.imgur.com/fpHOfTd.gif

[corradizo]

Re: Thoughts on Open Baffle Subs

+100

I have not done an IB but have OB bass bins and will NEVER go back to a box. After listening to my open baffles, I went back to my boxed speakers and could NOT BELIEVE HOW MUFFLED AND [email protected] they sounded. I really loved them before the OB's but once you listen to them compared to OB its game over for the box!!!

How do they differ? Can the ob go as low? As loud?

[zobsky]

Re: Thoughts on Open Baffle Subs

Consider a pair of drivers arranged magnet to cone in a "push pull" config per manifold . It will really help quell structural vibrations and even harmonics

[rmeinke]

Re: Thoughts on Open Baffle Subs

How do they differ? Can the ob go as low? As loud?

The quality of bass is excellent. Fast, tight and clean... but also sounds fuller and more power in the upper bass region. My dual 10's with the Jung 200W plate amp with 6dB boost is flat to 35Hz. I have EQed flat to 30dB as I don't listen at live levels very often.

They can go as low as you like with EQ. But compared to an traditional sealed or vented box you will need much more surface area and excursion to get similar output levels.

I think most OB guys will also say that you can get away with less than the best woofer to get excellent results. I would not have ever imaged that you can get superb bass definition from the Eminence Alpha-15A... but in OB you get fantastic results. You would NOT get these superlatives if you dropped them into a sealed or vented enclosure.

For my small 12 x 13.5 ft room dual 10's have way more output than I would ever need. Most folks are very satisfied with Alphas in an H frame. But you do see dual 15's often as well... I can't imagine.