OB for Lowther Pm6A

HPH

Member
2008-12-03 12:15 pm
I have just bought a pair Lowther Pm6A and really want to build open Baffle with PM6A, please kindly help me with your advice which project I should choose,.... My bed room is about 5.5x5x3m and my current system is Cayin A-88T, Rega P7,..
Thanks
 

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
If you had lots of space, I would point you to the 1m X 1.5m
OB size with an Eminence 15 Beta or comparable woofer. I
have gotten great results with this combination with both
active and simple passive crossovers.

Unfortunately, I looks like you have to consider something
smaller. Jon ver Halen and I have both had good results
with 24" X 60" and some rear side wings on the lower half.

You will end up crossing over at a little higher frequency,
but there it is.

:cool:
 
As Nelson mentioned OB's by himself and Jon Ver Halen, I dug this up.

Here's a picture of Jon's solid Maple OB from VSAC '08. He also used a Tone Tubby 16 ohm woofer crossed over @ 200 Hz.

From the front:

2.jpg


and the back:

3.jpg


It sounded excellent, in my rather conceited opinion.:D

Best Regards,
TerryO
 
Mr.Terry Olson,
Thanks. I have not a chance to hear OB with tone tubby yet but it's look good! can you please advice how the sound it's and detail of building this project.

I really dont know a great deal about it other than the Lowther and the Tone Tubby were both Alnico 16 ohm drivers and the crossover was a fairly simple first order design. To really have SOTA sound with a setup like this, you'd also need to have a subwoofer, Jon had a Hartley driver in his. I'd probably go for a distributed bass subwoofer system myself using 4 separate cabinets. This allows for smooth, unstrained bass without having to put up with room modes (Eigenmodes) with their Peaks and Suck-outs. Earl Geddes, among others, have gone into great detail on the advantages of Distributed Bass, so just do search if you want to hear it from horse's mouth.

Sound? It was, without a doubt, one of the very best at the Show. I'd love to have a pair.

Best Regards,
TerryO
 

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
Mr.Nelson Pass,
Thanks for your reply. Can you please advice the detail of the project "24" X 60"".

I haven't published, so I don't have anything formal prepared.
Take a look at the stuff TerryO referenced, and there is also
an RMAF blog by Jason Serenius on Stereophile showing the
Lowther/First Watt display. It looks like that but taller.

The crossover is pretty easy, but I'm still fooling around with
my passive version, and I won't be sharing that for a week
or two yet.

:cool:
 
...but I'm still fooling around with
my passive version, and I won't be sharing that for a week
or two yet...

:cool:


Hehe, we got hooked on Open Baffles, and hanging on crossovers :D

It's never easy to quit, and I don't want to. :) In this case, it looks like 1sr order crossover will provide that "something" that is lost with the 2nd order and higher crossover. The problem remains equalization on bass part, but hey, why not use a transconductance amp then...

HPH, just start somewhere, build some cheap baffles for a start, you will have a lot of fun tweaking, and tweaking... :cool:

Btw, Nelson, I guess you haven't tried Eminence Alpha 15 yet? :devily:
 
Tone Tubby

I wish I could find detailed information on the Tone Tubby, like a plot. It's the only reason I haven't bought them.

The 12" Alnico Tone Tubby

My Tiny Open baffle Alnico speaker (TOA) using the PM6A and the Tone Tubby is here:

Tiny Alnico Open Baffle

I do prefer the sound of the larger open baffles, especially on male vocals. If you have the room, you should consider the larger speaker.
 

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
He has already written somewhere that he prefers the Beta (which has a magnet). So I suppose he had tried both.

IMHO the Betas sounded better, specifically tighter and a
little more punchy. They also have more bass down around
30 Hz. The Alphas had more mid bass by virtue of their higher
Qts, and it could simply be a matter of taste.

On the issue of crossovers, the thing is to get some coils (5 to
20 mH), capacitors (50-200 uF polypropylene) and some
power resistors (8-16 ohms) and start playing.

The coil goes in series with the woofer, the cap goes in series
with the FR, and the resistors go across the drivers (if you use
them at all). Try the various values (remember to try
reversing the phase of one driver) and see what you get.

If you know what you like when you hear it, then all you need
is the time.

:cool:
 
Originally Posted by Jon Ver Halen:

I do prefer the sound of the larger open baffles, especially on male vocals. If you have the room, you should consider the larger speaker.

Do you think it is because of the wider Baffle or the bigger Bass Driver (416A in Case of the LOB)? Does it change whith Baffle Step correction ?

Beside it : What is your favorite Bass Augmentation for an Open Baffle Fullrange (Open Baffle Bass, sealed, something else)
 
Well, it depends

With a smaller baffle, using anything except an open baffle bass is audible. With a larger open baffle, the Lowther goes deep enough that you can get the deeper bass of a sealed box without much of an integration issue.

The real reason I prefer the larger baffle is coherence. The extra octave that the Lowther covers in the larger baffle sounds better. Additional bass is an extra added prize.