Speaker Help Please


Looking at a set of Jade 5's. I like the looks of the speakers but the specs are throwing me off. Most 3-ways I've seen run at 89 db but these are 87 db.
Can someone explain the sensitivity to me please. I included specs below. Thinking of running these with a Simaudio I3 SE. Thanx

Enclosure Type: 3-way Aperiodic system
Drive Units
  1 x 1" Alu high frequency dome
  1 x 3" Alu-pulp composite midrange cone
  2 x 6.5" Acufibre bass cone
Frequency Response: 42Hz – 24kHz ±3dB
Sensitivity: (2.83V @ 1M) 87dB
A/V shielded: no
Crossover Frequency: 340Hz, 2.4kHz
Nominal Impedance: 6Ω
Recommended amplifier power: 50 - 200W
mental
May want to have a look at this thread:

https://forum.audiogon.com/discussions/why-the-huge-discrepancy-in-sensitivity-ratings

@ gdhal...thank you for taking time with that. I forgot about the search function, need to spend more time in here than I have of late. Cheers
Hi Mental!

The reasons why a particular speaker ends up being 87 or 92 dB efficiency are complex, but have to do with the individual driver sensitivities, and choices made by the speaker designer in terms of the specific drivers used and also how much sensitivity they are willing to trade for bass extension.

I wouldn't be very concerned about a 2 dB difference in sensitivity, it's not a very good indicator of overall quality. Your ears are going to be much more discerning than that.

A 3 dB difference in efficiency implies a doubling, or halving of the power needed to reach a particular volume, but to double the perceived volume, you need 10x the power, or 10 dB (just happens to work out that way).

Unless you are listening far away, with a modest amplifier, a 2 or 3dB difference probably won't matter at all to you except where you set the volume knob while listening.

A more important measure in my mind is the minimum impedance. Some speaker makers deliberately lower the impedance curve in the mid-bass to make their speakers seem more selective of pricier amplifiers.

Otherwise, use your ears as a better guide.

Best,


Erik
Simply stated a sensitivity rating of 87 means that the speaker will produce 87dB at a distance of one meter with one watt applied. Every decibel above the sensitivity rating will require double the wattage, i.e. 2watts = 88dB, 4watts = 89dB, 8watts = 90dB, 16watts = 91dB, 32 watts = 92dB, etc. Speakers with a higher sensitivity like some Zu speakers @ 100dB and above will produce more dB or an higher SPL with less watts then say a speaker rated at 87dB. This is basic but should help better your understanding of sensitivity ratings. To better understand decibel, again simply put; a decibel is a ratio between two different power levels or sound pressure levels. A change in decibels is not linear, but logarithmic. An increase of 10dB would double the SPL (loudness)

Regardless of all the speaker hubbub,  In a normal listening room,  A Sim I3 will not have an issue driving these Wharfdales to very high listening levels. The information that you posted which may or may not be accurate shows that you have a 6 ohm,  85.5 db  sensitivity speaker,  the Sim should output about 150 watts per channel to these.  You should be fine.

Tim


"Every decibel above the sensitivity rating will require double the wattage, i.e. 2watts = 88dB, 4watts = 89dB, 8watts = 90dB, 16watts = 91dB, 32 watts = 92dB, etc."

That should be, every 3db above will require double the wattage. So, if 1 watt is 87db, then 2 watts - 90db, 4 watts - 93db, 8 watts - 96db, etc.


tls49s math is correct.
The formula that tls49 provided is correct (exempt the loudspeaker load for the sake of simplicity). Please excuse my error. I keep telling myself to get more sleep at night. 


Power in watts            Volume in dB
1                                       87
2                                       90
4                                       93
10                                     97
20                                     100
40                                     103
100                                   107
200                                   110
400                                   113

As you can see from the chart above and below, you can get a fair amount of volume (dB) out of as little as 32 watts of power (continuous) for a speaker with a Sensitivity Rating of 87 dB.
(exempt the loudspeaker load for the sake of simplicity)

Here is some other info that  provides a comparison between 87dB and 94dB speaker sensitivity and the comparative wattage to achieve the same decibel levels.

::: For a speaker with 87 dB sensitivity :::

Produces 87 dB of acoustic energy given 1 watt of power

Produces 90 dB of acoustic energy given 2 watts of power

Produces 93 dB of acoustic energy given 4 watts of power

Produces 96 dB of acoustic energy given 8 watts of power

Produces 99 dB of acoustic energy given 16 watts of power

Produces 102 dB of acoustic energy given 32 watts of power

Produces 105 dB of acoustic energy given 64 watts of power

Produces 108 dB of acoustic energy given 128 watts of power

Produces 111 dB of acoustic energy given 256 watts of power 

(exempt the loudspeaker load for the sake of simplicity)



::: Now for a speaker with 94 dB sensitivity :::

Produces 94 dB of acoustic energy given 1 watt of power

Produces 97 dB of acoustic energy given 2 watts of power

Produces 100 dB of acoustic energy given 4 watts of power

Produces 103 dB of acoustic energy given 8 watts of power

Produces 106 dB of acoustic energy given 16 watts of power

Produces 109 dB of acoustic energy given 32 watts of power

Produces 112 dB of acoustic energy given 64 watts of power

(exempt the loudspeaker load for the sake of simplicity)

Conclusion: With a loudspeaker with sensitivity of 94 dB, you can
produce a louder sound (112 dB) just with an amp offering 64 wrms.

Also note that speaker impedance will also predicate wattage requirements. But what has been posted above by the various contributors/members  should more than answer your question regarding sensitivity.




Thanks for the input, everyone. It's a good thing when one has a place to ask questions and get savvy answers. Cheers
Forget the specs and listen
@ sting, that would be my choice too, but sometimes that's not always an option. I research and ask questions about everything before buying, especially anything online. The Augon forum is a plus for that, always has been.
Once the speakers arrive i have a 30 day grace period to evaluate them, rest assured if I'm not happy I have no problem shipping them back even at my expense :)
One should never forget as in completely ignore specs. It is merely more data to consider in the overall evaluation process. 
great replies by all & looks like that helped mental.

one thing I’d like to point out is that the Jade5 is a 6 Ohms speaker (as mentioned in the spec).
So, if it’s 87dB @ 1m for 2.83V then doing the math gives
2.83V^2/6 Ohms = 1.33Watts.
Usually, the industry standard is 2.83V into 8 Ohms & then record the output SPL. With 8 Ohms & 2.83V you get 1W input power.
So, if you want to normalize the Jade5’s sensitivity to 8 Ohms so that you can do an apples-apples comparison with other speakers in the market, we need to do 10*log(1.33W/1W) = 1.24dB & then subtract this from the Jade5’s sensitivity of 87dB. We get 85.76dB = sensitivity of Jade5 normalized to an 8 Ohms speaker.

I DISAGREE with the Jade5 spec in that i disagree that it is a 6 Ohms speaker. I think it’s a 4 Ohms speaker (more about this later on in this post where I reference the Stereophile review & measurements). Keeping this in mind, I would simply subtract 3dB from the spec & say that the Jade5 is 84dB sensitivity normalized to 8 Ohms.

You can take this number & compare it to other 8 Ohms speakers & get a feel for the difference amongst various speakers.

i found a manual to you i-3 SE integrated amp here:
http://www.manualslib.com/manual/576290/Simaudio-Moon-I-3-Se.html?page=11#manual

you can see the output power rating into various speaker loads.
I did some rough calculations & what i’m calculating is that max current at 100W/ch into 8 Ohms is somewhere in the 2.5A region per channel. it is somewhere in the 5A per channel region for 160W/ch into 4 Ohms. Your mighty inefficient Jade5 lie somewhere in between these 2 current numbers.

i also found a stereophile review of your Jade5 here:
http://www.stereophile.com/content/wharfedale-jade-7-loudspeaker-measurements#wXE475EjpBqwa3gf.97

your speaker looks more like a 4 Ohms speaker than a 6 Ohms speaker (like I wrote above). In light of this I’m not 100% sure that your Sim Audio i-3 SE is adequate to drive this speaker to its best ability. i think that the output current is a bit on the low side. I’m sure you’ll get decent sonics from the i-3 SE-Jade5 combination. FWIW.



@ bombatwall...thnx for the input, makes sense. Always the option of throwing an amp in and using the I3 as a preamp, depends on those speakers. I like the look and the build is interesting, now for the sound. I'll post the outcome in a couple of weeks.
great! do keep us posted....
thanks.
Update on the Jade 5's: really nice looking speakers. I had a frown on my face when I first fired them up but as the day continued the sound became better. This mornin fired them up again and the sound keeps getting sweeter by the hour. Waiting on XLR interconnects, power cords, and bi wire jumpers. Once they arrive I'll give it a few days and post my thoughts. So far so good, the I3 pushes the speakers just fine. That was a relief :)
@ bombaywalla...you were right. The I3 pushes them for easy listening, tonite I threw some Skynyrd in. Speakers should have another 50 watts into addition what the i3 pushes out.
I am the village idiot, the I3 has no XLR inputs, assumed it did. lmfao
Had to send them back, think I’m going to stick with blue jeans rca interconnects, and maybe their 12 AWG speaker wire. Power cords, my designated circuit 6-8’ from both units, I went with Cullens. My system is not high dolllar and I don’t need to spend beaucoup dollars chasing tweaks for a decent sound. Anyone have a Simaudio 150 watt amp for sale...*laffs
Oh hell, guess I better check and see if it has pre-amp out, I don't remember seeing it. Thats messed up, I know it doesnt it without RTFM...*laffs. I'll have to deal with the setup, it doesnt get that hot to be concerned. The Jade 5's do require a beefier amp than 100 watts @ 8 ohms to appreciate what they bring to the table.