Speaker sensitivity

[Kitchener]

I’m having some trouble identifying the sensitivity of some old speakers.

The sensitivity is specified in watts.
4 watts to be precise.

And this translates to?

-the impedance is 4 Ohms.

[Paul Joppa]

Watts are not a sensitivity metric.

Sensitivity is a ratio of output to input. Usually (for speakers) the output is in dB SPL (sound pressure level) measured anechoically at a distance of 1 meter, and the input is in volts rms.

Older measurements, up into the Sixties IIRC, were done using different distances and different input metrics.

(Efficiency is similar, except the input is in watts. For a true efficiency, the output should be in acoustic watts, or the dB equivalent called "sound power," but that is hardly ever done.)

[Kitchener]

Yeah it makes no sense to me either from what I’m used to seeing.

These are old Tandberg (Norwegian) speakers from the 60-70s:
http://nrhf.no/Tandberg/TR%20Hoyttalere/t-hoyt-tl-1210.html

The only thing specified on the back is the impedance (4 Ohms) and their watts (40)

[Paul Joppa]

Yes, no sensitivity is specified on the linked page.

You might find a review (probably in a major magazine) that would give more information.

[Jamier]

     Is that model a HiFi12? I think Tandberg made several speakers with that woofer. It's an old school 6.5 inch paper woofer with an alnico magnet ( model htc 113?). I have seen that model and they have really simple crossovers, literally a cap and a coil on the tweeter and no components on the woofer. I believe that some of the larger models had somewhat more complicated xovers, although not much more complicated. I'm guessing that they come in around 87-89 db 1w/1M. You could probably drive those with a Stereomour II pretty nicely.

Jamie

[Kitchener]

I don't think so.
Their Hifi systems are usually clearly labeled "Tandberg Hifi X".
Here's a link to a Norwegian site that lists pretty much everything Tandberg: http://nrhf.no/Skjemabank/tb_info.php
They're generally pretty highly regarded around here, but that might just be national pride
Not so long ago, pretty much every Norwegian household had a Tanberg TV and radio (or Radionette), not anymore.


I got these after my grandfather died a few years ago, he used to listen to the radio on them every night.
-until the Tandberg radio (Sølvsuper 11) crapped out, currently trying to fix it but having a hard time of it.

So these are not sensitive enough for the SEX, you think?

[Jamier]

If they are in the 87-89 db range you could drive those with 2 watts, but perhaps not to the levels you want. Even the SII may not play as loud as you would like, it's a matter of personal preference.
I often use a 2 watt amp with 87 db speakers in a 12 x 15 foot room and it gets loud enough for me, so the SEX might do it under the right circumstances.

Jamie

[Kitchener]

Maybe, I’m considering selling my Crack to buy the SEX.
Our listening setup has the speakers about 6 feet away at ear level and we tend to keep it pretty quiet, so maybe.

[Doc B.]

I would assume that the 4W rating on the speaker means it can handle 4 watts max. So a S.E.X. amp should be a good safe match.

[Jamier]

I think the "4W sensitivity" specification is actually a minimum amplifier recommendation. The SEx is rated at 2 W (I think, I don't have one) but my experience has been that single ended class A amps will surprise you with their capabilities. I'm thinking that the SEX will probably do just fine, as long as your expectations are realistic. The Stereomour II would be better. I know it doesnt't offer you the headphone option ( although, I think Josh came up with an adapter) but it is an incredibly good loudspeaker amp.

Jamie

[Doc B.]

Yeah, you are right, they are rated for 25W max.

[Kitchener]

Well, I guess the only way to find out is to try 

[Jamier]

You could keep your Crack, use it as a preamp and build a Quicksand for a little more than $100. That speaker is a solid 4 ohm impedance, so you will get 8 watts, plenty of power to drive it.Then you would still have your headphone amp and a really good, yet inexpensive loudspeaker setup. I think the Crack will work as a preamp for the Quicksand. Maybe Doc or PJ will give an opinion.

Jamie

[Doc B.]

Quickie would work better with Quicksand because it has less gain and thus potentially better S/N, and it also has two inputs. But I think SEX would be a better sounding choice for use with both headphones and speakers.

[2wo]

Maybe, I’m considering selling my Crack to buy the SEX.
Our listening setup has the speakers about 6 feet away at ear level and we tend to keep it pretty quiet, so maybe.

If that is the case, then I am sure it will be fine. I mostly us a 45 amp with all kinds of speakers and if not looking for  window rattling, I say give it a go. I am currently playing with a pair of DCM Time Windows from back in the day, maybe mid 80's in sensitivity

The nice thing about tube watts is that you can push it a little, a little bit of clipping on peaks won't kill you speakers as long as you use some common sense...John