Lii audio 15” far open baffle speakers. How to fine tune. (2025)

opnly bafld said:

Big drivers can produce bass without a monstrous baffle.

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This is what I based mine off off.

Bassmantweed said:

This is what I based mine off off.

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Except the stand part right?

opnly bafld said:

Except the stand part right?

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hence the word based and not copied.

I’m learning here - last I checked that was the purpose of this forum. I thought it was all about surface area, not closeness to the floor. Most speakers you want at listening height. I guess I made a bad assumption raising them up.

Prob the easiest thing I could do is put a horizontal baffle behind the speaker on top of the stand to simulate the floor.

Bassmantweed said:

So the baffle serves what purpose???

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The sound from the back of the speaker is 180 degrees out of phase with the sound from the front and the baffle's job is to keep the two apart so they don't cancel. Low frequencies have longer wavelengths than high frequencies and are therefore able to "reach round" the baffle, so a baffle's ability to prevent cancellation of bass is determined by its size. If the baffle extends to the floor, the floor becomes effectively an extension of the baffle and gives you more bass. Basically, a bigger baffle gives you more bass. The maximum bass (or minimum bass cancellation) would be from a baffle of infinite size. That isn't exactly practical, but folding the baffle back on itself to enclose the rear wave completely does effectively the same thing, hence closed box speakers are also known as infinite baffle speakers. Of course, it isn't as simple as that, and the enclosed air space affects the driver's ability to move and sets up internal reflections etc. etc., so open baffle speakers still have advantages and still have their advocates. How big a baffle needs to be to give you "enough" bass is a matter of debate and a matter of personal preference. I take as a guide the Quad Electrostatics and the Wharfedale's SFB3 which are similar in size.

https://www.inner-magazines.com/audiophilia/wharfedale-sfb3/
https://audiokarma.org/forums/index.php?threads/wharfedale-sfb-3-first-impressions.823772/

Bassmantweed said:

This is what I based mine off off.

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Randy of Caintuck Audio designed those and I've not heard them. A friend at HH built those Barrel OB's with the 15's but for whatever reason soon sold them. But if you're not satisfied with the bass I've given a couple of options. The further you pull them out into the room the better they'll sound. Corner placement won't give them enough distance from the walls. Try floor placement without stands away from walls and with a back tilt.

If you decide to augment the bass you can build one stand alone matching baffle with a single woofer.

With 15 inch full range drivers you don't need this width but it shows the use of a single woofer for bass augmentation.

Although these monster folding baffles produced enough bass from an 8" Betsy driver for some folk's tastes I felt them somewhat lacking.

When I experimented by adding the Eminence bass woofers I knew that was the best direction for me.

Then I realized I could remove the wings and still have plentiful bass. These were made from one of the long folding wings of the original design.

rothwellaudio said:

The sound from the back of the speaker is 180 degrees out of phase with the sound from the front and the baffle's job is to keep the two apart so they don't cancel. Low frequencies have longer wavelengths than high frequencies and are therefore able to "reach round" the baffle, so a baffle's ability to prevent cancellation of bass is determined by its size. If the baffle extends to the floor, the floor becomes effectively an extension of the baffle and gives you more bass. Basically, a bigger baffle gives you more bass. The maximum bass (or minimum bass cancellation) would be from a baffle of infinite size. That isn't exactly practical, but folding the baffle back on itself to enclose the rear wave completely does effectively the same thing, hence closed box speakers are also known as infinite baffle speakers. Of course, it isn't as simple as that, and the enclosed air space affects the driver's ability to move and sets up internal reflections etc. etc., so open baffle speakers still have advantages and still have their advocates. How big a baffle needs to be to give you "enough" bass is a matter of debate and a matter of personal preference. I take as a guide the Quad Electrostatics and the Wharfedale's SFB3 which are similar in size.

https://www.inner-magazines.com/audiophilia/wharfedale-sfb3/
https://audiokarma.org/forums/index.php?threads/wharfedale-sfb-3-first-impressions.823772/

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@rothwellaudio

If I may just add the following info:

Stereo Sound Tube Kingdom Open Baffle from Volume 3, 1996 issue

It's quite obvious that the G.A. Briggs SFB3 design was the basis for the Stereo Sound OB which inspired me to build a pair for my Altec 755C + 755A drivers as featured in Sound Practices 17 in the late 90s.

Poultrygeist said:

With 15 inch full range drivers you don't need this width but it shows the use of a single woofer for bass augmentation.

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Actually this picture came from my open baffle blog. It was taken during the November Hifi Show 2008 in Manila where we demo'ed a stereo and a mono hifi system.

The outer mahogany finished OBs loaded with Altec 755Cs were the stereo system speakers while the center blonde OB loaded with an Altec 605B was the mono hifi system speaker.

A lot of visitors did think the center baffle was augmenting the bass output from the OB/755C.

setup1 said:

Actually this picture came from my open baffle blog. It was taken during the November Hifi Show 2008 in Manila where we demo'ed a stereo and a mono hifi system.

The outer mahogany finished OBs loaded with Altec 755Cs were the stereo system speakers while the center blonde OB loaded with an Altec 605B was the mono hifi system speaker.

A lot of visitors did think the center baffle was augmenting the bass output from the OB/755C.

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Are you saying the center speaker did not augment the bass? If so it might be due to it's low Qts.

Poultrygeist said:

Are you saying the center speaker did not augment the bass?

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Nope, it wasn't connected to the stereo set up. The Altec 605B/OB at the center was the speaker for the mono system.

If you click the hifi show link it will explain everything.

Mr Glow-in-the-Dark posted reviews of the Lii Audio 15 as well as two Altecs in open baffles.

http://glowinthedarkaudio.com/speakers.html

So I hear a lot about adding baffle but I am hearing a few different approaches. Maybe I need to do them all.

1. More baffle width.
2. Baffle on the floor
3. Baffles that extend back like “U”
4. Move into the room.

I guess I’m confused on which of 1,2&3 to do.

Bassmantweed said:

So I hear a lot about adding baffle but I am hearing a few different approaches. Maybe I need to do them all.

1. More baffle width.
2. Baffle on the floor
3. Baffles that extend back like “U”
4. Move into the room.

I guess I’m confused on which of 1,2&3 to do.

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Based on my old-school experiences playing with OBs linked above and what @rothwellaudio posted, 1 & 2.

Also. I have them toed in. What is traditional thought on towing in with open baffle speakers?

I will try moving them around but looking for guidelines.

Here's a picture of my mid 90s experiment with the OB/755C.

As a starting point, I used the rule of thirds placement recommended for the Quad ESL57s which I owned in the late 80s.

IME, this particular baffle design wasn't very finicky with placement - approximately 5-6 ft. from the back wall, 0.8ft. from the side walls and angled to my listening position about 8 feet away.

rothwellaudio said:

The sound from the back of the speaker is 180 degrees out of phase with the sound from the front and the baffle's job is to keep the two apart so they don't cancel. Low frequencies have longer wavelengths than high frequencies and are therefore able to "reach round" the baffle, so a baffle's ability to prevent cancellation of bass is determined by its size. If the baffle extends to the floor, the floor becomes effectively an extension of the baffle and gives you more bass. Basically, a bigger baffle gives you more bass. The maximum bass (or minimum bass cancellation) would be from a baffle of infinite size. That isn't exactly practical, but folding the baffle back on itself to enclose the rear wave completely does effectively the same thing, hence closed box speakers are also known as infinite baffle speakers. Of course, it isn't as simple as that, and the enclosed air space affects the driver's ability to move and sets up internal reflections etc. etc., so open baffle speakers still have advantages and still have their advocates. How big a baffle needs to be to give you "enough" bass is a matter of debate and a matter of personal preference. I take as a guide the Quad Electrostatics and the Wharfedale's SFB3 which are similar in size.

https://www.inner-magazines.com/audiophilia/wharfedale-sfb3/
https://audiokarma.org/forums/index.php?threads/wharfedale-sfb-3-first-impressions.823772/

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Like an idiot I passed on a set of these... TWICE!!! I did not know at the time what I know now.

kfa888 said:

Like an idiot I passed on a set of these... TWICE!!! I did not know at the time what I know now.

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To be honest, they would be easy to mistake for an antique oddity with no value, either sound-wise or money-wise. It was a novel idea of Gilbert Briggs to use sand to damp the baffles. At least, I'm not aware of any other speakers from that era that used the idea, or any modern speakers that do. My experience has been that the unsupported edges of the baffle are prone to flapping about, and having the stand/support behind that area and having sand-filled panels is an effective way to deal with the problem. I'm surprised we don't see the idea employed more often in DIY open baffles.

kfa888 said:

Like an idiot I passed on a set of these... TWICE!!! I did not know at the time what I know now.

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Wow, 2 pairs!

I've only seen this single unit at Elgin, IL radio show back in the 90s and a friend had a pair which I didn't get to hear.

setup1 said:

Wow, 2 pairs!

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No same pair offered twice. Still kicking myself years later.