Speakerplans.com Homepage
Forum Home Forum Home > General > General Forum
  New Posts New Posts RSS Feed - V-baffle for midrange drivers
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

V-baffle for midrange drivers

 Post Reply Post Reply
Author
Message
Tonskulus View Drop Down
Registered User
Registered User


Joined: 15 September 2017
Location: Finland
Status: Offline
Points: 425
Post Options Post Options   Thanks (0) Thanks(0)   Quote Tonskulus Quote  Post ReplyReply Direct Link To This Post Topic: V-baffle for midrange drivers
    Posted: 14 November 2018 at 6:33am
Couldn't find any discussion about this kind of design, where speaker baffle is angled so that drivers are somewhat facing to each other (tilt may range from 10..30 degrees or so). 
Any directivity or efficiency advantages / disadvantages?

In this case, there would be 2 x 10" or 12" drivers (frequency coverage 100-700Hz,  paired with JBL 2445 + 2380A horns ).



Back to Top
Jo bg View Drop Down
Young Croc
Young Croc


Joined: 08 March 2017
Status: Offline
Points: 552
Post Options Post Options   Thanks (0) Thanks(0)   Quote Jo bg Quote  Post ReplyReply Direct Link To This Post Posted: 14 November 2018 at 5:38pm
Hi
search tony Wilkes projects, he had some with v baffle and there was some discussion about it's merits.

the cavity should start loading the driver only over something like 500hz (depends on the depth and size of the cavity, 10-30° angle will make little depth i think), so there should be little difference crossing at 700, maybe a little raising response that could be overcomed shifting the lowpass lower.
DISCLAIMER, distant memories of old threads, could be wrong, but if you think about it as a horn/waveguide the small depth and mouth perimeter seems to confirm it will be effective only above those frequencies
Back to Top
dlyxover View Drop Down
Old Croc
Old Croc


Joined: 14 June 2007
Location: Liverpool
Status: Offline
Points: 1508
Post Options Post Options   Thanks (0) Thanks(0)   Quote dlyxover Quote  Post ReplyReply Direct Link To This Post Posted: 14 November 2018 at 6:31pm
As Jo bg said around 700-800Hz it will roll off also gets rather beamy.

I use a v baffle cab, 2x12" and BMS 1.4" coax.

I went for 90 degrees, did some test with various angles and acoustic lenses infront of the 12's to try and raise the roll off but effort vs effect did not really balance.

Very happy with the cabs performance over all.
In the Truth there is no news, and in the News there is no truth
Back to Top
MattStolton View Drop Down
Old Croc
Old Croc
Avatar

Joined: 04 September 2010
Location: Walthamstow
Status: Offline
Points: 4234
Post Options Post Options   Thanks (0) Thanks(0)   Quote MattStolton Quote  Post ReplyReply Direct Link To This Post Posted: 16 November 2018 at 11:57am
I recall the late Windmill tilter did a 8x8" in two columns of 4x8", on a V.

Measured a dip in response at 800Hz, which may have corresponded with a top to bottom standing wave, as much as a horn issue.

At low frequencies a V baffle will do squat. In the mids, when the wavelength starts to get of the order of magnitude of dimensions of the baffle/cab, then you will start to get affects. Almost becomes a very short tapped horn, if you squint hard.

On one of the many HR tutorials on HI-Fi sites, there is a diagram of a V baffle, with labels on which dimensions are S1-S4, Vtc, etc, to make converting design to HR easy.

Try this one: Linky

Build it, measure it, then throw your DSP at it - it is what everyone else is doing!
Matt Stolton - Technical Director (!!!) - Wilding Sound Ltd
"Sparkius metiretur vestra" - "Meter Your Mains"
Back to Top
moyano View Drop Down
Young Croc
Young Croc
Avatar

Joined: 12 May 2008
Location: Bedfordshire
Status: Offline
Points: 1219
Post Options Post Options   Thanks (0) Thanks(0)   Quote moyano Quote  Post ReplyReply Direct Link To This Post Posted: 24 March 2019 at 10:17am
Hi Matt, 

Do you happen to have a link to the 8x8 project ? 

I can’t seem to find it Smile
Back to Top
MarjanM View Drop Down
Old Croc
Old Croc
Avatar

Joined: 10 February 2005
Location: Macedonia
Status: Offline
Points: 7810
Post Options Post Options   Thanks (0) Thanks(0)   Quote MarjanM Quote  Post ReplyReply Direct Link To This Post Posted: 24 March 2019 at 3:15pm
Only benefit of doing a V baffle is to make the baffle area smaller.
The cavity is too small to have any significant horn loading effect and it will be at very small bandwidth that you would have to eq out anyway.
If you add a hf horn in front of it it will then create reflections and cancelations on some frequency.
The goal here is to play with the distance between the drivers and the angle to get the dips and peaks as much out of the intended band as possible.
Reflections can be somewhat dealt with by using some sort of foam at the back of the hf horn.


Edited by MarjanM - 24 March 2019 at 3:16pm
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713
Back to Top
MattStolton View Drop Down
Old Croc
Old Croc
Avatar

Joined: 04 September 2010
Location: Walthamstow
Status: Offline
Points: 4234
Post Options Post Options   Thanks (0) Thanks(0)   Quote MattStolton Quote  Post ReplyReply Direct Link To This Post Posted: 25 March 2019 at 10:41am
Originally posted by moyano moyano wrote:

Hi Matt, 

Do you happen to have a link to the 8x8 project ? 

I can’t seem to find it Smile

I couldn't find it either, when I wrote the previous comment!

However, I do recall he had a V baffle, each half of the V baffle had 4 x 8" drivers in a column, making a 4 high by 2 wide "array" of drivers.

He noted a marked dip in response at around 800-850Hz, which corresponded to the height of the V, or maybe the column of air height inside the cab (Windmill Tilter's usual array of braces on the inside)

The link in my above post, is to how to stick a driver in a horn, but not in the throat, at some point in the wall of the baffle/horn wall. It mentions that sound waves enter the horn at some point along the side wall, but go both ways, towards throat and out of mouth. Obviously those that go towards the throat, bounce out of throat, back towards mouth. At some point, there will be a cancellation between bounced throat wave and mouth directed wave. This point will be at some frequency which is a function of the distance of the driver from the throat, further from throat, the lower this cancellation effect.

Even though a shallow baffle is barely a horn, this effect will occur, but its effect will be mitigated by the shallowness of the "V" and the width of the driver (drivers are not point sources, the mouth end edge of cone is 8" nearer mouth, than the throat edge side of cone!). Deeper V will lead to a more pronounced effect.

As I said though; build, measure and then throw your DSP at it! Only way to be sure, and it also solves many issues...

I have found this thread, which mentions the same box, but with anomalies at 2K ish. https://forum.speakerplans.com/new-small-rig-for-live-use_topic55514_page1.html

There was another thread where he noted the 800ish dip, but I am buggered if I can find it!
Matt Stolton - Technical Director (!!!) - Wilding Sound Ltd
"Sparkius metiretur vestra" - "Meter Your Mains"
Back to Top
 Post Reply Post Reply

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.06
Copyright ©2001-2023 Web Wiz Ltd.

This page was generated in 0.109 seconds.