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Understanding Nautilus 804's

Summary:
I have seen many ads for B&W Nautilus 804's where they are being sold because people find they are fatiguing and have a lack of bass. As such, I feel completed to write this review / artical.


OVERVIEW

Certainly, the B&W Nautilus 804's are amongst the most aesthetically pleasing speakers made.
Don’t know if its true, but I’ve heard the natural cherry finish is the select finish and if there are flaws, the red stain is applied.

The mid / tweeter drivers on the N804's are quite accurate and this one reason why this is a highly strung speaker. They can sound wonderful if they are set up right or they can be outright painful with no bass if they are not set up right.

The retail on these speakers is about $4,800 Cdn.for the originals - don’t know the price for the diamond tweeter versions - N804's need matching High End equipment and cables to drive them. If you plan to drive them with Mid Fi equipment you are completely wasting you time and money and will end up with a frustrating experience.

The mid / tweeter drive units are identical to those used on the N803 and the crossover frequencies are at 4KHz and 300Hz for both speakers. From a marketing perspective, there is no way B&W could release the N804's with the same amount of bass that as that the N803's has. So these speakers can be a touch bass light and as such, should be matched up with bass heavy equipment.


WHO ARE THEY FOR

The N804's are for someone who wants to hear accurate timbres of instruments. They can reproduce the transient attack of a piano or snare drum quite well. Also, when I listen to them I hear instruments that were not noticeable before - like a lute that was previously buried in the Continuo.

Also, I would only recommend these speakers for someone who has the patience to constantly tweak them until they are pleased with the sonics.


BREAK IN

It seems like N804's take forever to break in - I would say at least 6 months of constant use. Just let them run while you are out of the house. Or even better - buy demos which are probably already broken in. Bao at Centek repairs, here in Ottawa, tells me that he thinks Nautilus speakers continue to mellow even after 5 years.


EQUIPMENT

I would suggest buying a matching CD player and amps for the N804's and finding cables to match the system. Also, I would suggest the selected CD player, Pre and Power amp be on the bass heavy side and have an analog sound. Clinical, harsh or grainy sounding CD players or amps will show up in an instant with these speakers and cause major fatigue.

The N804 are a difficult load to drive, and as such, they need a power amp that has a very low output impedance and can deliver lots of clean current. The Bryston 3Bsst is a well known match and a Sim Audio W-5 is an improvement over the 3Bsst. The Musical Fidelity Nu-Vista Integrated amp is also known to work well with the Nautilus series.

B&W, Rotel and Classe have the same owner, so you will frequently see B&W Speakers and Rotel amps in the same retail store. However, again the famous partnering is with a 3Bsst and again the W-5 is an improvement over the Bryston.

All this being said, I ‘m driving them with a H/K PA2400 power amp which is a Mid Fi amp that may not be the last word in finesse but can drive a difficult load and is on the bass heavy side.

The speakers are bi-wired with mid / tweeter at one connection. The carbon fibre woofers are at the other connection with a cross over frequency of 300Hz. I have never heard anyone horizontal bi-amping N804's with a tube amp connected to the mid / tweeter connection and a bi-polar amp connected to the bass. Not sure why this is not being done, but getting the phasing right may be the reason.

A preamp sets much of the sound stage for a system. I have gone through a whole string of preamps trying to find one that matches the N804's. A Musical Fidelity A308cr has very low distortion, soft but neutral sonics and solid accurate bass so this preamp matches quite well. Although I’ve never heard one, but a BAT tube preamp is supposed to be an improvement even over the A308cr. I would say a MF 3.2cr is a bit bass light to be partnered with the N804's.


As a source, I’m using a Linn Karik iii / Numerik ii. This CD player is a touch bass light and could have a touch more dynamics, but has quite a good analog sound. Its absolutely critical that the CD player used with the N804's has no harshness or grain. Although I’ve never heard one, a Meridian 500 / 563 is known to have an analog sound and have solid bass so it might be a good match. A Sim Audio Moon Eclipse CD player is stunning with Nautilus speakers.

One thing I do have to say here is that some DAC’s can be affected be affected by the quality of the digital stream they receive - the transport. So using a Harman Kardon CD player as a transport and then trying to get great sonics out of a Monarchy 24 tube DAC is not going to work The N804's will reveal all the harshness of a source like this.




CABLES

For the mid / tweeter drivers I use 2 metre AudioQuest CV-6 with the dbs system. This cable has noticeably low distortion and sounds very accurate and neutral. I prefer the sound of copper over silver plated cable. The slower dynamics of the CV-6 calms the Nautilus tweeter down a bit and the 2 metre length seems to be about right. The CV-6 is a good match but I wish there was just a touch more in the way of dynamics.

For bi-wiring the woofers, a cable with very low resistance is required. Actually, a subwoofer cable may be ideal. I use a 10 AWG silver plated cable made for a company called KnuKonceptz and the model is called KASA 10 and it is quite inexpensive. I find the bass is quite well defined using this cable and this is a good match for the N804 woofers.

For interconnects, usually I prefer the sonics of all copper over silver - I’m using AudioQuest Vipers and I know I’m going to get fan mail for this AMX copper interconnects.
Sometimes I use Luscombe solid silver Litz interconnects with cardas RCA’s.

For digital cables, its critical to use true 75 ohm digital cables. Silver 75 ohm have much less harshness than an RG-59 (?) Cable. Between the Karik and Numerik I use a silver QED digital cable, with true 75 RCA’s, and a tributaries cable with BNC’s.

Power cords defiantly make a difference - I made my own using Belden 19364 cable and bought the IEC connectors and hydro plugs from Omer at Oz.

My power amp gets plugged straight in the wall. However, the Preamp and CD player gets plugged into a Line filter very similar to Jon Risch’s DIY design.


TWEAKS

One person on Audioreview recommended adjusting the tension screw behind the mid range driver. DO NOT do this. This is what holds the mid range driver in the cabinet and its tension is set at the B&W factory.

One modification I did do - the whole volume behind the woofers is completely stuffed with urethane foam blocks and foam also blocks the bass port. After removing the woofers, I removed about 2 litres of this foam and replaced it with foam just at the back of the cabinet. The foam I used has the same shape as that used in an aneholic chamber. Certainly the bass is stronger now and a resonance or boominess is not really noticed . Make you have the technical skills if you attempt this. Also, mark the polarities on the woofer wires and protect the woofers from allen screw damage.

For placement, I toe the speakers into the room and they are almost - almost facing the opposite corner. Also, I have them angled away from the listener.


SUMMARY

The N804's are Accurate and Enjoyable if they are set up with an analog sounding source, a low distortion preamp and a power amp that can drive a difficult load. If there are any flaws in the equipment trying to drive them, they will expose this and the result will be a fatiguing or even harsh experience. Also, realize N804's take an unusually long time to break in.


Underhill


Written By: Uunderhill on Jul 17, 2007


Comments / Replies on This Review

Re: Understanding Nautilus 804's


There is a clarification I should make here:
Most DAC's are sensitive to the quality of the transport they are used with. Higher quality transports have lower bit error and have less bit jitter.
So using a quality DAC, like a Monarchy DAC, with a cheap transport, will not yeild good results.

However, bit stream jitter can be significantly be reduced by adding a circuit called a PLL - Phase Lock Loop - between the transport and DAC. Monarchy makes a PLL they call a DIP.
Adding a Monarchy DIP, to a Monarchy DAC, will make a massive inprovement.

As such, I recommend using a Monarchy DIP & 22C DAC with the N804's. The Monarchy DIP & 22C combination has great warmth, dynamics, noticably good channel separation and instruments are quite focused. Very importantly, using the Monarchy DIP and 22C, the N804's do not have any hint of harshness or fatige.

Since originally writing this review, I tried Kimber 8TC speaker cables connected to the mid/tweeter of the N804's.
8TC's are good cables, but IMHO are not right for this application.
For biwiring the N804's mid/tweeter, I much prefered AudioQuest CV-6's.


My reference test CD's are

Brubeck - Time Out

Mozart - Piano Sontas K.310, K.331, K. 533/494
Murry Perahia
Sony SK 48 233

By Uunderhill on Dec 30, 2007
Re: Understanding Nautilus 804's

Good job - looks like you put a lot of effort into this. I'm not a B&W owner, but if I was, I'm sure I'd find this useful. Should have been titled: "Uunderstanding Nautilus 804s."

cheers,
ben

By ben on Feb 1, 2008
Re: Understanding Nautilus 804's

Since originally writing this review, my system has now become

Linn Karik iii transport on a block of foam underneath
---> QED QNECT 75 Ohm digital cable
Monarchy Classic DIP with the clock upgraded by Lawrence at Excel Stereo
--->QED QNECT 75 Ohm digital cable
Monarchy M24 tube DAC with PCM 63 K DAC chips and Amperex PQ white label 6922 tubes
M24 DAC plugged into a Chang Light Speed

---> 0.5 m silver Litz interconnects similar to Luscombe's

Musical Fidelity A308cr preamp
---> AudioQuest King Cobra analog Interconnects
Musical Fidelity A3.2cr power amp
--- AudioQuest CV-6 speaker cables

and of course N804's.

Since the B&W FST midrange driver and Nautilus tweeter is so accurate,
it really helps to have output tubes in the digital source.

Tweaks are critical to getting great sonics from a source.
Lawrence's clock mod, to the Monarchy Classic DIP, is well worth the $100 upgrade.
Also, foam underneath the transport makes a noticable improvement.

By Uunderhill on Nov 14, 2008
Re: Understanding Nautilus 804's

Great Review. You really do understand the speaker. I own the B&W N802's. Mine are fully broken in and sound beautiful. I also do not experience any listener fatigue at all. I purchased mine back in 2005 brand new as my final pair and they will continue to stay in my system. I even like the looks of mine better than the new ones. Dave

By Art837 on Aug 29, 2016

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