Low sensitivity in practice

[admin_exported]

What does low sensitivity mean in practice? I know that I will need a more powerfull amp to drive them. Take 2X60w amp (Nait XS) and 85 db/m speakers. Does that mean that I would simply have to turn the volume higher? And if you connect it with 91 db/m?

I like listeninig to the music at low volumes and, of course, you don't get to hear all the details from it. Does it mean that I would hear more details with 91 db sensitivity at the same volume compairing to the 85 sensitivity?

Maybe I didn't but the question right... hope you get the picture.

 

[Anonymous]

May I refer you to this letter:

Clicky

Basically the low speaker sensitivity will result in you having to turn up the volume and work the amp harder to get the volume versus high sensitivity. Low sensitivity speakers may never go that loud because you'll only get so many decibels out of them for their power handling. It all depends on the speakers really.

Low sensitivity seems to come with small speakers, especially small infinite baffle boxes. This is because an infinite baffle requires the amp to work harder to move the drive unit against the sealed box volume, e.g. Spendor SA1. Also, a small drive unit can be made to produce excellent bass response by having a larger magnet and higher power demands, e.g. Dynaudio Focus 110.

 

[Anonymous]

In practise it means that you need a much more powerful amplifier to drive low sensitivity speakers satisfactorily. For a 60 watt amplifier the max SPL you will get from 85dB/m speakers is approx 97dB. That may be fine for you if you only listen at low volumes - but the day you want to rock (rock music can easily peak at over 100dB) your amplifier won't be powerful enough and will clip. A 91dB sensitivity loudspeaker would be much better for your small 60 watt amp. Your existing amp would drive these to 103dB SPL which is adequate.

 

[Anonymous]

Your small 60 watt amplifier is really insufficient to drive 85db (1w/1m) sensitivity loudspeakers. For low listening volumes it will be fine but if someone wanted to play some rock music (which regularly exceeds 100dB for short periods) your small Naim amp would clip and sound harsh.

If you don't want to change your amplifier then it would be better to obtain some loudspeakers which have better than 91dB sensitivity.

 

[Anonymous]

Thanks, guys!

I was considering some high quality speakers like Pro Ac D18 (88db/m), just waiting for the right review from WHF.

Maybe Spendor A5 or A6 but looking at the sensitivity (85 db/m and 86 db/m), I was thinking it's better to buy ProAc.

Or PMC FB1 (90 db/m).

I like all kind of music and I have ProAc Studio 110 at the moment. They are quite nice, to be honest. I just need some more bass from floorstanders. Subwoofer is not an option.

 

[Cypher]

I don't know if sensitivity is that important. The Dali Lektor 2 has a sensitivity of 85db and my Rotel RA-04 drives them with ease. The B&W 685 are 88db and are more difficult to drive.

 

[Anonymous]

Surely this all depends on how close you sit to the speakers? Also acoustics will play an important role because reflections will give a boost to the dB level also.

Generally I'd agree that 60W isn't going to get a lot of volume from 85dB speakers. From my experience you should look to 100W plus. The only way to determine for sure is an audition.

 

[Anonymous]

Cypher:
I don't know if sensitivity is that important. The Dali Lektor 2 has a sensitivity of 85db and my Rotel RA-04 drives them with ease. The B&W 685 are 88db and are more difficult to drive.

Indeed there's a difference between sensitivity and resultant volume, and impedance characteristics that make a demanding load. My Spendors are less than 85dB W but have an easy impedance characteristic making them an easy load. Naim amps cope very well with difficult loads because of the amount of current they can muster up from their huge, stiff power supplies.

I think auditioning is the only way to really get a feel for this. It's not like you're looking to use a fee-powered valve amp.

 

[chebby]

Are small insensitive - infinite baffle - near-field monitor type speakers really supposed to be operated with vast amounts of power at huge volumes? I did not think that was the point of owning them.

 

[Anonymous]

chebby:
Are small insensitive - infinite baffle - near-field monitor type speakers really supposed to be operated with vast amounts of power at huge volumes? I did not think that was the point of owning them.

Indeed, and I suspect a key point here is near-field. You'd be surprised how much power such little beasties suck up though. Imagine how much voltage you need to get a pair of less than 85 db W speakers singing with their surprising bass response. Mini power station needed.

 

[chebby]

Usually such speakers have a soundstage designed to occupy a space of a particular size (in the case of LS3/5A, spaces like OB trucks and small regional radio station 'studios' etc.)

More power does not necessarily make the 3D 'image' wider or bigger in a larger room. Just louder.

I have read of many Ls3/5A owners experiencing this stubborness of the 3d image to 'grow' when used in a large room.

 

[Anonymous]

I think the latest incarnation of LS3/5 has come forward a bit. Take the SA1 for example. The scale that they offer is huge for such a diminutive box. There's only so much picture that you can paint with 'ickle drivers anyway. Decent bass response does indeed seem to make big demands on the final sensitivity.

 

[Anonymous]

Here's a calculator to help you understand what volumes are possible when comparing loudspeaker sensitivity to amplifier power. BTW, the way amps work, going from 50W to 100 W will give you 3db extra. Not much is it?

http://www.crownaudio.com/apps_htm/designtools/elect-pwr-req.htm

In the example I chose, my speakers are 88db 1W/1m. In order to listen to them at that level 3m away, I need - wait for it - an 18w amp. If I want to listen to music at 100db from the same speakers, 3m away, with 3db headroom, I need an amp that can generate 285 watts. To go from 90db to 100db requires the amp power to go from 28 watts to 285 watts.

If you google "speaker sensitivity amplifier power", some interesting articles appear.

I don't know if any of that helps?

 

[chebby]

Given that prolongued exposure to sound intensity beyond 78db can result in permanent hearing damage and that 100db is equivalent to listening to a pneumatic drill at 1 metre, then why would you want such levels?

(Bear in mind that accurately reported sound pressure levels are usually measured anechoically or outdoors. A typical room can double the perceived volume depending on the furnishings.)

 

[manicm]

Cypher:

I don't know if sensitivity is that important. The Dali Lektor 2 has a sensitivity of 85db and my Rotel RA-04 drives them with ease. The B&W 685 are 88db and are more difficult to drive.

I am using the 685s with my 25w Solo Mini and they're not hard to drive at all, admittedly in my small space which will become bigger soon. The trick is the Solo Mini is real 25w at 8 ohms.

What I have noticed, and others bear this out even with much more powerful amps, is that you won't hear them at their best at low levels. From normal to moderate levels is where they start to sing, and at rocking volumes is where they start to really sing.

I think it's a bit of a myth that the 685 is not a sensitive speaker, I personally think anything from true 40w at 8 ohms on can handle them easily. And they're quite flexible too, within reason. They can even sound good on a solid table, provided each corner has equal side wall proximity.