KEF R3 + Marantz NR1711 / Bi-Amping?

nikku888

Novice Member
Hello,

I’m just starting to learn about all this, reading forums, appreciate any input at all.
  • I have a Marantz NR1711 + some old DALi Concept 2 bookshelf speakers.
  • Looking at upgrading those to KEF R3’s soon (and hoping for distinct difference in audio enjoyment)
  • I will eventually get a seperate power amp (Peachtree?) and use the pre-out on the NR1711 to drive the R3’s.
  • The NR1711 is due to space (height) constraints and I’m only using 2 fronts and a centre (maybe a sub later).
  • Rarely does the volume go above 50% due to apartment living, mostly listen around the 25% level.
I have two questions:

1. Should I set the NR1711 to 4-ohm mode, given the R3’s can dip to 3.2ohm at some frequencies? Or leave it at 8ohm / default? Will it make a difference?
2. Any point to using the unused surround channels and bi-amping the R3’s with the NR1711? On another forum, it was suggested this is in effect bi-wiring and won’t make any difference. Even though the Marantz manual calls it bi-amp mode?

Thanks
 

gibbsy

Moderator
Leave the amp at it's default 8 ohm and forget bi-amping. You'll not be gaining anything as it's passive bi-amping where the power will just be stolen for the remaining connected speakers. Even bi-amping will not make up for a probable poor recovery when the KEFs dip to 3.2 ohms. A power amp, or more powerful and higher tier Marantz would give the R3s a better chance to perform to the level that they are more than capable of.
 

rccarguy2

Distinguished Member
Bi amping does make a noticeable difference, in two channel hifi (say if you had four monoblocs or two identical stereo power amplifiers) but not worth it with avr and mismatched power amps. I'm using 2x2ch and it is improved over just the one
 

Mr Wolf

Well-known Member
If it's true bi-amping (not bi-wiring) which engages extra unused amps then it can make a difference, especially if the power supply isn't being overly taxed which it probably isn't at your low listening level. I would certainly give it a try. The situation where it makes no difference at all is where the PSU is maxed out (i.e. current limited) so bi-amping becomes a zero-sum game.

Are you using a sub? ASR measured the R3 has having a nasty <3-Ohm impedance dip around 42Hz which ideally will be taken out with with a bass management crossover to a sub. For music I'd probably be crossing these speakers to a sub at 60Hz given their f3 point of 58Hz.

1650794423320.png
 

nikku888

Novice Member
Leave the amp at it's default 8 ohm and forget bi-amping. You'll not be gaining anything as it's passive bi-amping where the power will just be stolen for the remaining connected speakers. Even bi-amping will not make up for a probable poor recovery when the KEFs dip to 3.2 ohms. A power amp, or more powerful and higher tier Marantz would give the R3s a better chance to perform to the level that they are more than capable of.

Ok, thanks. There is only 1 other speaker (centre). But am probably leaning towards putting in another amp sooner rather than later anyway.
 

nikku888

Novice Member
If it's true bi-amping (not bi-wiring) which engages extra unused amps then it can make a difference, especially if the power supply isn't being overly taxed which it probably isn't at your low listening level. I would certainly give it a try. The situation where it makes no difference at all is where the PSU is maxed out (i.e. current limited) so bi-amping becomes a zero-sum game.

Are you using a sub? ASR measured the R3 has having a nasty <3-Ohm impedance dip around 42Hz which ideally will be taken out with with a bass management crossover to a sub. For music I'd probably be crossing these speakers to a sub at 60Hz given their f3 point of 58Hz.

View attachment 1687411

Thanks for this detailed response.

No sub currently. Possibly a KC62 later on, but living in an apartment I had complaints previously when I had a sub 😐

I’m gathering that if I want the most out of the R3’s at all frequencies including the nasty 42Hz where it dips I’ll probably need a seperate amp to drive these. Currently looking at the SA-01 from KJF that uses a Hypex module. But might bi-amp first with the NR1711 and see.

I’ve no idea what an F3 point is will go look that up - frequency at 3ohm I guess.
 

Mr Wolf

Well-known Member
I’ve no idea what an F3 point is will go look that up - frequency at 3ohm I guess.
The f3 point is the frequency at which the speaker plays 3dB below its flat response line. At bass frequencies 3dB lower equates to being about 30% quieter which is a fairly significant drop.

It's usually quoted in the specs as part of a frequency response range. KEF quote this as being 58Hz-28kHz (±3dB) for the R3. There's an upper f3 point too (28Hz) but nobody cares about these as with modern tweeters they're always above the 20KHz threshold of human hearing.

In effect the f3 point represents a limit of a speaker's reasonably accurate bass extension so if you're using a sub the bass management crossover should always be set above this frequency.
 
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nikku888

Novice Member
Thanks for this. Beginning to understand.

So below the f3 point, it doesn't matter how powerful your amp is, it's diminishing returns in terms of output from the speaker?

After everything, I think I'll be looking to add a separate power amp sooner rather than later. Have discovered a Purifi-based amp that's put together in Australia (March Audio) - so I'm looking at that. I figure 265W of power into 4ohms should be enough for the R3's.
 

rccarguy2

Distinguished Member
Thanks for this. Beginning to understand.

So below the f3 point, it doesn't matter how powerful your amp is, it's diminishing returns in terms of output from the speaker?

After everything, I think I'll be looking to add a separate power amp sooner rather than later. Have discovered a Purifi-based amp that's put together in Australia (March Audio) - so I'm looking at that. I figure 265W of power into 4ohms should be enough for the R3's.

Say you had very little speakers, 3" drivers. There is no point in setting them full range, or small 60hz. You'd want to set to around 120hz, at least. The same principle with yours, they aren't full range so for AV it's not a good idea to have them full range. They'll be fine for Hi-Fi in pure direct (full range) from CD.
 

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