what boxes to build for Lowther PM2?

[bigswede]

Hi there,

I went to a flea market the other day and found a pair of Lowther PM2 drivers. An old man sold them to me (never used, still in the box) for about $80, which i guess is a steal...

What should I build for these babies? Any tips? Is there anything out there that will give me decent bass reproduction for, let's say, modern acoustic singer-songwriter type of music...?

And how do I tell if they are "A series" or "C series", and what is the difference?

Thanks for any replies...

Ola Gustafsson,
Skara, Sweden

[talaerts]

A has alnico magnet, C is ferrite. Probably A sounds (even) better. Is the magnet painted red? Then it's likely an "A". If the magnet has a black ring then it's likely a C. In any case, for your money, you made a really good deal.
For cabinets, if you have the space and 2 available corners, then I would make the "Big Fun" horn design. I downloaded the plans a long time ago from a Norwegian site.
Pictures of a CNC'd kit version:
http://www.creationaudio.com.au/Lowther.html
Plan: http://www.lowther-america.com/bigfunv21.pdf
The width isn't indicated in the plan but the CNC variant measures 1150mm tall, 885mm deep, 470mm wide, and it has very likely the same external dimensions.

Otherwise, I would have a look at the original Lowther designs on Enclosures to Build and see which seems to fit your living room. You can order detailed plans (with cutting info) from Lowther.
FYI, for the PM2A, Audio Technik GmbH recommends the old-fashioned looking Acousta 115 (close to the Acousta 116 on the lowther UK page) or the Fidelio when using a small distance ring between driver and cabinet.
Photos of the enclosures:
Acousta 109 / Acousta 115
Bicor 200 / Bicor 250 / Fidelio

A modern design is the Medallon by Lowther America, it is also popular with the PM2A:
Medallion
(with link to plans)

Even if you have the PM2C, I would still check out the above designs first. They seem best with drivers that have already stronger magnets.

[Paco]

Here you can see the step by step construction of a Lowther Fidelio cabinet. It's in Spanish but I think that google translator will do the job:
Construcción de unas cajas toda-banda: Lowther Fidelio - Audio-blog de Audiohum - Audiohum

[pengesluk]

Originally Posted by bigswede

Hi there,

I went to a flea market the other day and found a pair of Lowther PM2 drivers. An old man sold them to me (never used, still in the box) for about $80, which i guess is a steal...

What should I build for these babies? Any tips? Is there anything out there that will give me decent bass reproduction for, let's say, modern acoustic singer-songwriter type of music...?

And how do I tell if they are "A series" or "C series", and what is the difference?

Thanks for any replies...

Ola Gustafsson,
Skara, Sweden

Indeed - only in Sweden would this happen - someone selling a new pair of Lowther's for $ 80.00

[PeterDupont]

Once ran a PM2 in a 70 cm.long tube filled with woll, crossed 1st.order at 500 Hz with a inductor to tame the high-end lift.
The most detailed, transparent and dynamic presentation I just have heard from my new Iwata's.
Allthough the excursion was about plus/minus approx. five mm. when hammering the 211 amplifiers full, they sang for three years before I had to experiment otherwise.
We used four Scan-Speak wofers pr. channel, each two running isobaric in closed boxes with Q-0.5. Having about 15 watts from each 211 monoblock it was more than enough to lift the celing.

[Leonidas]

Tried several solutions for lowther; tqwp some compressed horn designs etc.
None satisfieing, you need real BIG horns for lowthers!!
Now running them open baffle.
Bi-amped with open baffle bass.

A 70cm tube with Karlson slot is another option, also with a (sub) woofer.

[talaerts]

I once heard an expensive box that featured a modified Lowther (that is to say, one that had undergone a whizzer-ectomy) augmented with tweeter and woofers, so the Lowther was used purely as a refined midrange unit without suffering from its usual limitations and complexities.
I think it was a predecessor of this one:
Eufrodite
And if I remember well, it was based around a big Lowther.
In any case, it did sound marvelous indeed.

[Nelson Pass]

Open Baffles. Take a look at what Jon ver Halen is doing at
Lowther America:

Home

[hm]

Hello,
a few constructions are useful for the PM2A, look my
Schalmei, Trumpet and Horn sat,
and with an invers indirect driver a SPH-210 Monacor or similar
the double horns SAXOPHON and RDH20.