Will 88db speakers play well with an F5?

[Hikari1]

Fellow F5 users:

It's time for new speakers. I currently have a pair of Focal 714v, 91db 8ohm (4 ohm min) that I can drive to 95db levels pretty easily with a BA-3 preamp (20ish db gain). It starts to compress any louder than that which is about 3/4 up on the volume dial. I have a very large room (open floor plan), probably 700 square feet. I have no problems driving these Focals but I haven't used any other speakers with an F5 in my room. 95db is loud enough for me.

I've been looking at new towers, I don't want DIY anything (I have no wood working tools and like to work late at night wehn the kids are asleep...hard to "quietly" build speakers). I don't particularly like the full-range single driver thing. Wife would never go for open baffles and I need speaker grilles or they will become kid toys.

That being said...here's what I am looking a and they are mostly 88db-ish. I am trying to stick with something with a higher impedence...is this wise? Also, is it better to look at something with a less complex crossover which in my mind means a two way or 2.5 way vs a 3 way?

What are using for speakers with your F5 and any success driving 88db-ish towers?

Anyways, here is what I am looking at:

KEF R500
Design Three-way bass reflex
Drive units Uni-Q driver array:
HF: 25mm (1in.) vented aluminium dome
MF: 125mm (5in.) aluminium
Bass units: LF: 2 x 130mm (5.25in.) aluminium
Frequency range (-6dB) 39Hz - 45kHz
Frequency response (±3dB) 46Hz - 28kHz
Crossover frequency 500Hz, 2.8kHz
Amplifier requirements 25 - 150 W
Sensitivity (2.83V/1m) 88dB
Harmonic distortion
2nd & 3rd harmonics (90dB, 1m) <0.4% 120Hz-20kHz
Maximum output 111dB
Nominal impedance 8Ω (min. 3.2Ω)

PSB Imagine T2
34-23,000Hz 36-20,000Hz 36-10,000Hz 29Hz
88dB 90dB
6 Ohms 4 Ohms
20-300 Watts 300 Watts

Focal 826V
Type: 3-way bass reflex floorstanding loudspeaker
Drivers:
2x 6.5" shielded Polyglass Woofer
6.5" shielded Polyglass midrange
1" TNV inverted dome tweeter
Frequency response (±3dB): 45Hz-28kHz
Sensitivity (2.83V/1m): 91.5dB
Nominal impedance: 8 ohms

 

[Blues]

If 95db is loud then you need about 5 watts to get there on a nominal 8ohm 88db/1watt speakers. I say lots of headroom with an F5 and a passive preamp.

 

[Hikari1]

If 95db is loud then you need about 5 watts to get there on a nominal 8ohm 88db/1watt speakers. I say lots of headroom with an F5 and a passive preamp.

I understand the math. I tried a passive pre, it was less dynamic and lacked drive. Also, I was running out of volume control, literally maxing it out.

I should note that this is a BIG room with very high ceilings.

At the listening position I usually listen at around 85-90db. With a BA-3 preamp and the F5 I am 3/4 of the way up on the volume control at 90db listening levels. This is w/91 db sensitive speakers. If I get 88 db speakers I am worried I will regret it.

 

[stijn001]

My 2 cents, the F5 is in a different league (if it's a proper example), don't ruin it with these power hungry "dull" sounding speakers. Go with a quality high efficiency "full-range single driver thing" with a bit of bottom augmentation if nessesary and minimal filtering. Going out on a lim I'd say that's what the F5 is ultimately made for. Otherwise, surely a good audio shop will allow you to bring your F5 along for an audition.

 

[AndrewT]

I understand the math. I tried a passive pre, it was less dynamic and lacked drive. Also, I was running out of volume control, literally maxing it out.

I should note that this is a BIG room with very high ceilings.

At the listening position I usually listen at around 85-90db. With a BA-3 preamp and the F5 I am 3/4 of the way up on the volume control at 90db listening levels. This is w/91 db sensitive speakers. If I get 88 db speakers I am worried I will regret it.

Passive pre-amp, i.e. a volume potentiometer without a Buffer, can seriously degrade the audio signal reaching the Receiver. Careful design compromising of component values and cables is required to get the best out of a passive pre-amp.

Adding a buffer can make a big difference to sound quality.

Inadequate volume has nothing to do with passive pre-amp and little to do with maximum power.
It's all about system gain. The F5 has ~+16dB of gain, the passive pre-amp has +0dB of gain.
Many Sources cannot give adequate sound volume with only +16dB of gain, try adding 6dB to medium output sources and adding +12db of gain to low output sources. High output sources can drive the F5 to near maximum or above maximum output. Your big room may use big listening distances. That will have a big effect on the apparent volume. Listening at 800mm (desktop) is different from listening at 2m and different again from listening at 4m.
Read
http://www.diyaudio.com/forums/diyaudio-com-articles/186018-what-gain-structure.html
It's on (or linked from) the front page of our Forum for a reason.

 

[ticktock]

I currently have a pair of Focal 714v, 91db 8ohm (4 ohm min) that I can drive to
95db levels pretty easily with a BA-3 preamp (20ish db gain).

Although Focal claims the Chorus 714V to be 91 dB, it is not. In fact it's ~87 dB:

http://www.focal.com/de/index.php?controller=attachment&id_attachment=3154

Commonly most manufacturer's data is false. 😉

With an F5 I'd definitely look for something like this:

Odeon Audio Lautsprecher Systeme - Odeon Audio Hornsysteme

Odeon Rigoletto de speaker bij de hoorns Odeon Rigoletto de speaker bij de hoorns

Dietiker & Humbel Multimedia: Herr F. aus Seuzach

An externally hosted image should be here but it was not working when we last tested it.

 

[Hikari1]

Interesting. I knew a lot of you would recommend single driver, very efficient designs. But honestly, i think the f5 drives my focals fine. And, as tick tock has pointed out, they may be truly a 88ish db sensitive speaker. If i can get clean 95db music peaks iam fine.thats enough for me. I would love to try out some single driver stuff for comparison but other than diy its pretty hard to find in my city.

 

[ticktock]

With a proper 2-way design you won't miss anything.
In a backloaded horn cabinet such a Vifa 7" driver will beat most 10" drivers in bass-reflex.
Those horn speakers sound awesome with an Aleph J. I'd bet they will also do with an F5.

 

[KevinHeem]

I'm listening to a pair of Focal Chorus 826 VW as I'm typing with a F5, B1, and Pearl 2. The sound is wonderful. The volume is fine for me, but I don't listen terribly loud. You need to look at the impedance curve of the 826(Focal Chorus 826W 30th Anniversary Edition loudspeaker Measurements | Stereophile.com) and then the distortion curve for the F5 (http://www.firstwatt.com/pdf/prod_f5_man.pdf). Because the impedance of 826 dips below 3ohms and the F5's distortion spikes like a brick wall at 50 watts into 2ohms I think I'm playing with fire a little bit. I listen in a room that's about 14' X 35' X 8' but my listening area only takes up less than half of that. Like I said the sound is fantastic. I would definitely spring for the W version. I paid about 2 grand on the used market. Hope this helps a little.

 

[AndrewT]

Because the impedance of 826 dips below 3ohms and the F5's distortion spikes like a brick wall at 50 watts into 2ohms

Is there a pdf that shows or discusses this?