Seventh Veil

for info, I had a pair of sbls, and hated them....they were sooo anxious, I had to take a valium to calm down...very edgy, not nice to listen to IMO, but each to his own...

its the small scanspeak tweeter, proac use these, and too have a slight edge...possibly inherent in the tweeter...


heard the nbls via nap 500 didn't seem as edgy, but could be the room and other things...lots of cash tho'

good luck steve

 

Naim speakers need a lot more control than one is lead to believe. i've never been that impressed by DBLs and the NBLs have always been regarded as fairly uncrontrollable. But the advent of multiple spurs, decent power amps (300s & 500) or at the very least active kit.

Less than that and I agree they can be fairly painful. Get it right and you're up and dancing.

 

Was it the DBLs that Paul Messenger had for many years (biggish boxes)? That guy has ears. :respect:
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BTW Tom, your Naim amps don't have phonos do they?

Ideally we need two preamp outputs. Can your Naim pre oblige?

The first goes straight to one of your Naim power amps (stereo) and then to the Nonsuch 4s. That should be easy.

The second goes to an active filter unit input (phonos for L & R).

From the active filter output (phonos for L & R) we go to another stereo power amp and then to the Little Awesomes.

I'm bringing an active filter and the speakers. Do you have the leads to plug into your Naims for the above? If not, what do we need to sort out?

 

I'll email you the rear plans etc and full list of my kit

 

Agreed Robbo, but you know me, abrasive is my middle name

But I was interested that you mention Neat as using the purely subjective method. Didn't you all find, as did the review in HIFI+ that there was a strange problem in the bass with the Neats

Possibly due to interaction with strange surroundings. I doubt that the designers heard thatwhen they were designing the new series. Just a thought.

I'm always up for a comparison with the JBL/Dynaudio sub/sat combo, very similar prices I think so it could be interesting.

 

Yes, I did find that the bass was a bit overblown. Could just be that the speakers were way to big for the room. I'll need to try the smaller ones to be able to draw a more definitive conclusion.

I still think subjective listening is the most important aspect of speaker development.

 

Absolutely, as is the subjective tweaking of the system using cables, supports, and mains filters.

What I would prefer is to start from the base where everything measures correctly, then when you adjust it subjectively, at least you know what is causing the improvement in musicality. then you can always go back to the ideal if you run into trouble.

I spent nine months subjectively tweaking the response of my setup for my room. Being able to see exactly what was happening at each stage was educational, helping me to understand how to achieve a certain balance and grasping the effects of measured peaks and nulls in the frequency response.

I learned that I personally prefer the top four octaves to be shelved down by a couple of db with a gentle rise in the top octave. Also just how important linearity is in the bottom four, and the subjective effect of altering this balance. With this data, I no longer have to start from scratch, but using a computer alone without the aid of my ears would have resulted in a very boring sound indeed.

 

Dear Merlin

This is the part that interests me and if the two of us can discuss this in a constructive way then I would like to do so, if you're willing. I don't believe for a minute that you're a complete duffer and nor do you. Partial duffer? hmmm - no, just kidding, really!

I am interested to know which information on my site appears to you as "rather easily picked apart, even by a complete duffer". The site contains my design philosophy not a collection of marketing palliatives so if you disagree with any of my concepts, I would like to know which and why.

I suspect from our correspondence that the main area where your ideas might conflict with mine are in the bass region. Is this right?

You have stated your view that time alignment errors in the bass are audible and that these are only masked by room resonances (which should be ameliorated by the correct room treatment).

Here, I'm in broad agreement with you, with the proviso that my company manufactures speakers and that many of my customers may be unwilling to adequately treat their rooms.

But here's where you lose me a bit ...

Some people hold the view that the subs should be placed in one corner of the room so that the room modes are fully engaged. I tend to hold the view that all rooms are different and while this is often the best approach, sometimes it's better to use two subs and experiment with positioning to achieve the optimum. In this case we're talking a 4th order, low-pass filter on the sub with a -3dB point of 100Hz. (that's as far down as I can comfortably run the full-range speakers at full output).

In the paragraph above, you talk about two subwoofers (plural), against the back wall. What would be wrong with placing the two subs on opposite side walls, where they could be closer to the listeners than the main speakers? Could you explain what you mean when you say that the transient response and bass impact of the subs is compromised when they're moved away from the back wall?

Perhaps you could start by briefly summarising your basic beliefs on what makes the best subwoofer positioning? Then I would at least understand where you're coming from.

Often, people hold genuinely different views on what makes a good sound in hi-fi. That doesn't always mean that one of them is wrong. They might both be wrong or both right. I've said this before but I think it's worth restating. The loudspeaker design process is a question of choosing the compromises that you prefer in order to achieve the sound that you think is the most real.

I'm willing to discuss these matters openly on this forum. This is because I'm confident in my skill as a designer and at the same time because I realize that everyone has something to learn. This is probably unusual for a speaker manufacturer. If people conclude from this that I'm an amateur or hobbyist or that my speakers don't work, they are mistaken.

There's plenty of time for them to take that view after they've heard them. :beer:

 

LMAO! "Anxious", that's the most succinct single word description I've aptly heard applied to the "Old Skool" Naim sound. Even makes your adrenalin rush with music that's supposed to be relaxing.

Quite right though, each to their own.

...but I wonder if folks who like the (older) Naim sound are predisposed to being a bit hyperactive, fidgety and have a lot of nervous energy. Certainly, one Nait 3 owner I know would seem to fit this mould!

 

Steve,

As you may have seen, Merlin (Michael) is a huge supporter of the TACT 2.2 system and, from what I've seen, his views on room acoustics (including strategies for subwoofer integration) come primarily from them (which in not necessarily a bad thing ) - so it may well be worth searching out any papers from Tact to see where he's coming from.

 

Graham is quite right that my interest in room acoustics was started by researching the Tact product. Not one to take marketing blurb at face value, I have done research to see just how valid some of the theories are, and have also been able to do some practical experiments that appear to back them up.

As a caveat, I work from a slightly different script, as I have to take less account of room effects than you do, that said I still do need to place the speakers in my room optimally, it's just that I can iron out some of the problems that arise from this positioning, and accept less of a compromise.

The first point comes straight from Peter Lyngdorf's thinking, but is backed up by simple physics. Whilst the directionality of sound increases with frequency, it is accepted that bass notes, due to the long waveform, are omnidirectional, radiating at 360 degrees from the transducer. This, in a typical enclosure generates a backwave, which will rebound off the rear wall, potentially invert phase, and then arrive at the listening position.

The first problem is that the sound of the reflection will arrive later than the direct portion of the sound. If your subs are two feet out from the back wall, the reflection will arrive four ms or so after the direct output, having the effect of blurring the LF energy over a period of time (in this case 4ms). In addition, this backwave can, due to it's inverted phase, act to cancel out the direct sound, paricularly at certain frequencies (this dependent on the distances involved. Hence we have uneven, weakened and time smeared bass response.

The answer is to remove the backwave, this is done (in the case of Tact and Nestorovic) by firing the bass units into the rear wall or corners at very close range. This ensures that the back wave arrives at the same time as the direct sound, and that it is in phase with the direct sound over the operating range. This leads to reinforcement rather than cancellation, and to less smearing in the bass. The result is less colouration, and greater transient attack.

It is widely accepted that the interaction of speaker directivity and your listening room is a key factor in getting good results. I believe that controlled directivity, aimed at suppressing the destructive contribution of the listening room, should be a design priority.

Now going back to point 1, we already have, in your setup, a potential delay for the reflected bass soundwave of 4ms. When we then place the satellites three feet in front of the subs, this delay extends to 7ms, quite considerable. And that assumes that the bass units employed are of sufficiently low moving mass to show a similar rise time to the ultra fast Bandors. I can say that, from my subjective experience, this delay will lead to a percieved increase in ambience and body, at the expense of transient snap and timing. That's not to say your speakers don't subjectively sound excellent, just that it may be possible to improve on them.

You may also be interested to know that I find the least compromised position for the satellites is up against the side wall This again ensures that the first reflection is in time with the main output, and that it's spectral balance is very similar (assuming you have a hard plain wall).

Of course, both of these optimal solutions can lead to problems elsewhere. In particular, corner mounted subwoofers will excite first and second harmonic room modes and cause uneven bass. This is where I advocate equalisation, to cover the lower frequency decade. It is also, as the above indicates, not a bad idea to delay the signal from the satellites sufficiently to ensure that the wavefronts from both them and the subwoofers launch at the same time.

I hope that helps to clarify my position. I might add that, whilst there is plenty of empirical data to support the above, the proof has been in subjective testing carried out over the past nine months.

 

Thanks for that merlin. An interesting approach.

In what way would you say that the Seventh Veil loudspeaker system is unable to work in the 'Tact' mode that you describe? Which systems are recommended for this approach or does one have to buy Tact speakers or subwoofers?

My other question relates to parametric equalization. I haven't used it myself but my understanding is that it is best used after other room bass treatments are in place. Also that, whereas bass traps and other room treatments can have an effect throughout the room, equalization is only effective for a specific listening position. Have you found this to be so and how large is the area for effective listening?

 

I have to disagree with some of that logic, Merlin.

If your bass is omnidirectional, and you fire your bass driver into
the rear wall, corner or wherever, then the "back wave" is simply
radiating back into the room - to bounce off 6 walls, 8 corners
etc...
Your "1st reflection" is from wherever it arrives 1st! It doesn't
have to be the rear wall/corners behind the speakers.

The tact [et al] works by using more amplifier power/speaker output
to cancel reflected sound. Similair result to the other approach:
damping your room with absorbtion - you need more power for a given SPL, for the benefit[??] of less room sound

Low pass filters will delay the sub sound anyway.
Moving the sub towards the user is a reasonable solution to time-align at a specific freq [say, to add signals at the level where the outputs are X-ing over, or to cancel at a frequency where there is a room node]. Of course, the picture is way too chaotic in any
room to be exact, and highs arrive sooner from the sub than lows due to the LP filter.
If you bring the lows forward in time to synchronise, the residual
hi-bass from the sub will be ahead of the main spkr output
I for one think this is a GOOD thing for rock, as it helps to reduce
the dead/nuetered sound of CD drums/bass etc, which is not the fault of CD standards, just those dumb engineers and their limiters...

Steve, if you want to try conventional filters for room correction,
this is how I would do it.

Use a mono graphic/parametric/whatever only.

You seperate the sound into M-S stereo ie:

L+R = M=middle

L-R = S=side

This is easy with balanced equipment, or look for a
"shuffler"/stereo width circuit

Then you do [bass only] room correction on the L+R signal

then stick the sound back together

Far superior to farting about with Left and Right channels seperately, since bass standing waves are mono [ie L+R]

cheers,

Graham C

 

Hmm, in that case I wonder if these speakers are made in the same factory then:

http://www.metropolis-music.co.uk/manufacturers/lumley.htm

 

Hi Graham,

I think you might have interpretted this the wrong way. If you fire a drive unit directly into a wall, say 2 inches from the cone to the surface, indeed you will get a backwave firing into the room. It's point of origin will however be within 0.3ms of the first reflection, and hence it's arrival time will also coincide. In this way, the full horizontal output of the bass driver is forced forward at the same time. The vertical output is another case altogether.

Exactly what we don't want to do, we need to delay the signal to the satellites surely.

Why, is the speed of sound requency dependant around 100hz

I prefer to think that the Tact actually removes the excess energy that is an artifact of oyur room and nothing to do with the original recording

Nor have I sir

This is not really the Tact approach, similar approaches to bass directivity are employed by Martin Logan, Naim eek: ), Linn and others. The use of sub, sats to avoid the compromise of bass response vs. imaging however is really the Tact domain. As you are marketing a sub sat setup, pointing to these very benefits, it is fair to point out that your setup, without the ability to adjust delays between the units, will be compromised when the seperate transducers are placed optimally.

 

You're right, merlin. In this area my speakers are compromised.

As I have said (more than once): "The loudspeaker design process is a question of choosing the compromises that you prefer in order to achieve the sound that you think is the most real."

So I have chosen to have a full-range speaker with no crossovers or electronics between the power amp and the drive units (except cable and I'm looking at cooking and cryo-ing that ). I just love the openness, transparency, detail and speed that this approach brings.

I can't see myself putting any sort of delay circuit anywhere in the signal path to these speakers. I'm sure there would be gains made but also losses. I want to play to the speaker's strengths, not dilute them to make someone else's idea of what good sound reproduction should be.

That's not to say I don't enjoy listening to other people's systems and choices. I love to. I'm sure that with the thought, care and time you have put into your own system, I would be enormously impressed by the sound that has been achieved. But it wouldn't be my sound.

Isn't that the beauty of high end hi-fi? Isn't that why this field is a love and hobby for all of us and a profession for some? After all, if someone, anyone, had all the answers, what on earth would we be discussing here?

Vive la difference!

 

I'm sure that they do sound great, and I do like the idea of full range drivers avoiding the need for crossovers in the vital midrange.

If you are ever interested in trying the digital route, feel free to contact me, I would be interested to hear how the satellites perform in tandem with my own subs.

Just for reference, in a Tact setup, there is also no electronics in circuit between the power amp and main speakers, all crossovers and correction is carried out in the digital domain prior to this stage.

The best of luck

 

I'd certainly be interested in listening to that. How high do your subs go at the moment?

If I only had to put the Nonsuch 4s in the car and leave my subs at home, so much the better.

Where about are you?

 

Steve,

My current sub can only be crossed over at up to 120hz, due to it's filter.

The new subs, using JBL 15"drive units will be able to cross over at anything up to 800hz, and still be well below break up, although the plan is to experiment with anything from 100hz up to 325hz to avoid lobing. Being able to crossover at say 200hz should improve the power handling of the Bandors.

We can set the slope at anything from 2nd order to 10th order, all dsp generated of course. We can of course just set a low pass for the subs, and leave the satellites alone. Experiment is the order of the day.

The subs are a few weeks off yet, the cabinets are currently being built. But it would be an interesting test for sure.

 

Yes I'm looking forward to hearing these beastie's, powered by Digital Grunt of coarse ,a lot of work and effort gone in here, should reap some serious rewards
Me I'm not a speaker guy (other than knowing what sound I like) Timpy is the clever guy in this dept, Mr 5th order modified Horn
I spotted this on Meadowlark site yesterday stunning or what
I have a pair on order too, but not in that colour WM

Nothing less than a work of art