Matching Speakers to amp


I currently own a PSA Stellar 300 paired with Focal Aria 926. I just picked up a used pair of Quad S-5 and I will be comparing the sound. I am not good a using technical specs to compare so I could use some help if anyone has the time to take a look at the amp & speaker specs below and give me some feedback I would greatly appreciate.
The basic question is: from a specification standpoint which speaker pairs up with the Stellar 300 best?


Stellar 300
Gain30.5dB +/-0.5dB Sensitivity for rated output power1.01V Noise1kHz@300 Watts <-100dB Input impedance S300Unbalanced 50KΩ
Balanced 100KΩ Input impedance M700Unbalanced 50KΩ
Balanced 100KΩ Output Impedance50Hz, 2.8VRMS <0.007Ω Damping factor50Hz. 2.8VRMS
8Ω >1100
4Ω >550 Frequency Response@2.8VRMS
10Hz – 20KHz +/- 0.5dB
10Hz – 50KHz +0.1/-3.0dB
Output PowerBoth channels driven 120vac mains, 1kHz, 1% THD 8Ω140W minimum 4Ω300W minimum 2Ω Stable for musical transients

Quad S-5
General description 3-way floorstanding speaker
Enclosure type ABR
Transducer complement 3-way ABR 165mm x3 Bass driver 165mm Woven Carbon fibre Cone x2
Midrange driver 125mm Woven Carbon fibre Cone Treble driver 12 x 45 mm
True Ribbon Sensitivity (2.83V @ 1m) 90dB
Recommended amplifier power 25-175W Peak SPL 112dB
Nominal impedance 6Ω
Minimum impedance 3.2Ω
Frequency response (+/-3dB) 42Hz ~ 23kHz Bass extension (-6dB) 35Hz Crossover frequency 570Hz & 3.2kHz

Focal 926
Speaker driversTwo 61/2" (16.5cm) Flax bass61/2" (16.5cm) Flax midrange1" (25mm) Al/Mg TNF inverted dome tweeterFrequency response (+/- 3dB)45Hz - 28kHzLow
frequency point - 6 dB37HzSensitivity (2.83V / 1m)91.5dBNominal impedance8 OhmsMinimum impedance2.9 OhmsRecommended amplifier power40 - 250WCrossover frequency290Hz / 2400Hz











128x128jbuhl

you have more then enough power for either speaker. both are relatively efficient 90db, 91.5db. both seem to have similar specs but both dip to 3ohm load or slightly below but you have more then enough power for this load. so go for it see what sounds best to you.

your amps make 300w into a 4ohm load as your speakers are nominal 6-8 ohm dipping to 2.9 ohm and 3.2ohm  your good to go.

so for future ref. the speakers sensitivity is an indication on how loud they will play with usually 1w at 1 meter (2.83v @ 1m is an indication they are rating the speaker at 8ohm load)

the Quads are not as efficient as the Focals but not that much, you probably wont notice the difference.


probably the most relevant info you need.

Quad:   Sensitivity (2.83V @ 1m) 90dB ;

how much power you need for a given volume level, lower the number the more power you need generaly

            Nominal impedance 6Ω
            Minimum impedance 3.2Ω ;

 this tells you how hard they are to drive higher is easier lower is harder. lower impedance will require an amp that can drive that load SS amps are better at low loads then tubes for example.

            Frequency response (+/-3dB) 42Hz ~ 23kHz ;

 how much of the frequency your speakers will perform in the average room. humans can hear from 20hz to 20khz (well only children and woman can hear that high but you get the idea)


Focal:

Sensitivity (2.83V / 1m)91.5dB

Nominal impedance 8 Ohms

Minimum impedance 2.9 Ohms

tweeterFrequency response (+/- 3dB)45Hz - 28kHz


other will most likely chime in and add or correct if I missed something



jbuhl
The basic question is: from a specification standpoint which speaker pairs up with the Stellar 300 best?

Sorry, but to me neither speaker will be at their best with the Stellar, it will work into them and probably sound fine, but probably not extract the best from either. >2ohm loads are not Class-D’s forte.

I don’t think big wattage is the answer here as both speakers are over 90db, a 50-100w amp will do, the issue is the amp needs to supply good current into the low bass load as seen by it (below) to keep it from becoming a tone control.

The Quad S5 has a demanding load in the low bass.
As measured by Keith Howard of HiFi News:
" EPDR (equivalent peak dissipation resistance) to fall to a minimum of 1.4ohm at 111Hz, making the S_5 a more than a typically testing load for this size and class of floor stander "

The Focal Aria 962 is also a hard load in the bass as can be seen by this graph from 80hz to 300hz. 2.8ohms and also a -55 degree phase shift, which equates to a EPDR well below 2ohms
https://www.stereophile.com/images/1114FA936fig1.jpg

A Class-D, Tube or Mosfet is not my first choice of amp for loads like these to get the most out of the low bass of these two speakers.
I would prefer to see a linear amp with lots of bi-polar (BJT) output devices and big power supplies, to push current into that bass to keep it under control and flat without becoming a tone control..

Cheers George


"The basic question is: from a specification standpoint which speaker pairs up with the Stellar 300 best?"

The question was not what amplifier(s) best suits these speakers. The question was which of the two speakers best suits the amplifier. As mentioned earlier, given the similarities between the two speakers’ specifications, you’d just need to listen to both and compare the two in your room and decide which one sounds better to YOU. I haven’t heard the Quads but if the Focal 926 sounds anywhere near what 936 sounds like, I’d guess you’ll like them better. Given that you have them all in your home, this appears to be a no brainer approach. Let us know how you make out.
Yeah just looking at the numbers nothing jumped out at me as being wildly different twix the 2 speakers.  So I expected a response to be "They close".    Now I am excited to see if I can tell the difference between Focal downward facing  bass ports and flax cones vs Quad's kevlar cones, ribbon tweeters and rear facing auxilary bass radiators.   One thing I really like is the classic fit and finish on the Quads.