JR 149s

[Howard Stone]

What are people's experiences with JR 149s?

I have a pair being driven by a Quad 520 . The sound is not very satisfactory -- it sounds "amplified" I wonder if people have found a really successful amp for them.

Someone I know loves the sound he gets out of them with a leak ST20. Thats 10W per channel. But it turns out that he listens very vert close and very quietly. I want to be able to listen in a smallish room -- 15'x15' -- though not to loud music -- a harpsichord or a handful of voices max or a few string instruments max.

And then there's the question of positioning. Does anyone think that the wall brackets Jim Rogers produced are a good idea for the sound? I have mine on stands but close to a wall, 10'apart.

Oh my source is an old Deltec Bigger Bit DAC; no preamp.

I'm toying with the idea of getting a PASS Aleph 30 clone for them.

It may be that these speakers were designed for near-field monitoring and it's just not possible to get a satisfactory room filling sound from them.

[Peter Wieck]

Howard:

In the interest of full disclosure, I have NOT heard that speaker specifically. But, and commenting on the nature of small speakers:

a) Its rating is +/- 3 dB, 70hz - 20 Khz. While respectable, this will not fill even a moderate sized room. Keep in mind that the woofer is less than 4.5 inches (110mm). In a more ideal world, that is a lower-midrange, not a woof.
b) The amp at ~100 wpc or so, will not be to blame. Those are relatively efficient at 89 dB @ 1 meter @ 1 watt.

The smallest speaker I have that is capable of making good noise is the AR4x, with an 8" woofer. They do just OK in the smallest room in the house (14 x 11 x 9 (feet)) driven by a 60-watt vintage AR amp. The speakers you have are the functional equivalent of the satellites on my AR Athena Sub-sat system.

I will bet that these started life, conceptually, as monitor speakers, not as full system speakers, and their limitations are due to that start.

Now, in a room approximating your 15x15, I am running a pair of AR3a speakers from an vintage AR Receiver (80 watts into 4 ohms). That is a 12" woofer, dome mid and tweet. Do fine. And that is what you need to move sufficient air to fill such a room.

The library - main listening area - gets the Maggies and a brute-force amp to handle them. The best way to fly, in my opinion.

Peter Wieck
Melrose Park, PA

[dpierce.ca...@gmail.com]

The JR's are very much based on the BBC LS3/5a design,. It uses the
same KEFB110/T27 set of drivers and a somewhat similar crossover.
Both of these drivers are VERY good, but especially the B110, it's
a 5" mid/woofer, perhaps on the best every made, but it's still
only a 5" mid/woofer.

Now, as to the design goals for the original LS3/5a, I would refer
you to the original design brief,

"There is a need to monitor sound programme quality in
circumstances where space is at a premium and when head-
phones are not considered satisfactory. Such circumstances
include the production-control section of a television mobile
control-room, where the producer responsible for the overall
production of the programme needs to monitor the output from
a sound mixer but at levels lower than those used for mixing."

Hardwood, Whatton and Mills, "The Design of the Miniature
Monitoring Loudspeaker Type LS3/5A", BBC RD 1976/29, pub.
Research Dept., Eng. Div. British Broadcasting Corporation,
1976 October

So, imagine a large trailer pulled up to a remote venue, and said
trailer is divided into several "rooms", one of which is for the final
monitoring of the "programme". Said trailer might be 10-12' wide, and
the room might be 8-10' long. The producer might be sitting in front
of a console, and as a result the producer listening might be sitting
all of 5-6 ft away from the speakers, which themselves might be 4-6 ft
apart.

This is the scenario the speakers were designed for. Your friend's
scenario is much closer to the design intent than yours.

As to what amplifier is "best", I think that is, at best, a tertiary
issue. The venue and use scenario is the dominating set of limiting
factors. I would posit, and be willing to back it up objectively,
that, used in the right way, it makes little if any difference whether
you're using it with a quad 520 (100+ watts/ch), a Leak, a Pass
or whatever up to the level common to what all of them can produce
without distortion.

The point being that the speakers were intended for moderate monitoring
in a small venue.

What subsequent uses were invented by the high-end, and claims about
the suitability in those scenarios, is another question altogether,
and, like much in the high0-end, may not be constrained by inconveniences
like facts, physics or reality.

As usual.

[Howard Stone]

I am afraid that you are right, Mr Pierce. Such a shame!

[Howard Stone]

I'm afraid that you too are right Mr Wieck. Such a shame again!

[Howard Stone]

Do you think it would help to stack two pairs of them?

They are cute, cheap, have a sweet midrange, easily sellable. So I’m exploring even the most off the wall options!

[dpierce.ca...@gmail.com]

No. Many of the advantages they have are due to their physically
small size and, except right around the crossover point, their
small size acoustically. Stacking a pair of them will make the
vertical dispersion worse, will make the overall frequency and
power response worse, will make the size of the vertical "sweet
spot" much smaller (this would manifest itself in making for
audible variations in the response as you move your head up and
down: listen to broadband noise as you move your head around and
you'd see what this means).

They're very good for their intended use and, like most things that
are very good for their intended use, they're not so good doing things
they weren't intended for.

The whole "stacked pair" thingy was a craze started in the '70's,
and, when done properly with things like Quad 57's, the results
could be very impressive (though MOST implementation of stacked
Quads did NOT do it properly). On the other hand, another popular
combination was stacked Advents, which were 'okay" speakers but
because of a. their physically large size, b. driver placement
on the baffles that prevented getting drivers close together
and c. very minimal crossover slops that ensured the drivers
overlapped across a very broad band, more than they should have
to begin with, the results were demonstrably less than 'okay'.

[Howard Stone]

Thanks for the reply. I’ve never heard stacked ESL 57s. Someone tried to sell me a pair of them quite recently for a good price (assuming they don’t need servicing soon) - but they’re just too big for me, however wonderful they sound.

I wonder if you know of any other speakers which are good to stack. Small ones, very small ones, preferably.

[Peter Wieck]

I think you are crying out for a sub-sat system. Your SO will appreciate the (relatively) tiny satellites, you will appreciate the relative ease of placing those satellites, and the sub-woofer becomes something that may be hidden reasonably well.

A room that is 15 x 15 is at the upper limits of such a system, but the Revox Piccolo comes immediately to mind as something that will function in that venue. Not a power-pig either. My 15 year old granddaughter has my set - and she loves them. Her room is oddly sized, about 12 x 18 for a floor plate, but under the eaves.

https://www.picclickimg.com/d/w1600/pict/192916516918_/Enceintes-Revox-Studer-Piccolo-MKII-system.jpg

[dpierce.ca...@gmail.com]

On Friday, June 7, 2019 at 11:05:50 AM UTC-4, Howard Stone wrote:
>
> I wonder if you know of any other speakers which are good to stack.
> Small ones, very small ones, preferably.

As a general principle, stacking speakers not designed to be
stacked is a bad idea.

In your particular case, you're starting with small speakers
essentially designed for close proximity listening in small
rooms at moderately loud levels. Getting another pair of the
is not going to make much of a difference in terms of how well
they will play broad-band material at high levels, and will
make the combination worse in a number of other ways. If you
like these speakers, stacking another is as likely as not
going to make you like the result less.

One of the other correspondent's suggestion of adding a subwoofer
to the system could be beneficial, if and only if it's done
right, and that means relieving the main speakers task of doing
what it's not good at doing: playing low frequencies at any
appreciable levels (I don't mean LOUD). That would means restricting
the amount of low frequency information sent to the mains, e.g.,
restricting the mains tro >15Hz, at the lowest.

If done right (and that's a big 'if'), it could work out well for you.


[ I am pretty certain Mr. Pierce typo'd 150Hz there, for 15.
-- dsr, your mostly uninterfering moderator ]

[dpierce.ca...@gmail.com]

On Monday, June 10, 2019 at 9:11:28 PM UTC-4, dpierce.c...@gmail.com wrote:
> One of the other correspondent's suggestion of adding a subwoofer
> to the system could be beneficial, if and only if it's done
> right, and that means relieving the main speakers task of doing
> what it's not good at doing: playing low frequencies at any
> appreciable levels (I don't mean LOUD). That would means restricting
> the amount of low frequency information sent to the mains, e.g.,
> restricting the mains tro >15Hz, at the lowest.

> [ I am pretty certain Mr. Pierce typo'd 150Hz there, for 15.
> -- dsr, your mostly uninterfering moderator ]

Yes, 150 Hz, not 15 Hz.