Why the probelm with large English brand names?

You also need an amplifier to match those rather nice decent floorstanders in order for them to reach their FULL potential, plus a forgiving room

 

Not quite like that - it's simply perceptual (psychophysics). The brain as is now today doesn't need to analyse what is importnat for it to happen. IIRC they are simply curves where the subjects matched the perceived loudness of tones at different frequencies. One curve for each ball-park level of sound pressure that the experimenter started with. The general picture is that extreme low and high frequencies need to be higher sound pressure to be equal perceived loudness with middle tones. This is true at all levels, but more so the quieter the starting point - that's what the old 'loudness' buttons (spuriously) claimed to compensate for.

Maybe that is what you meant. If anyone wants details, I can drag a book off the shelf as I am a psychologist and got taught this stuff many moons ago. (Doesn't mean I interpreted you right, though)

 

Hi Markus,

If there are problems, I don't think there's very much I can do about it! It will be interesting nerdery, and I'm looking forward to meeting Merlin +/- A.N.Other. Most of the people I've met from these forums have been very nice.

 

Hey, don't you guys start getting mushy or lovey-dovey on us.

 

OK.

Merlin, have you seen my PM?

 

You're quite right that the FM 'equal loudness curves' are simply curves where the subjects matched the perceived loudness of tones at different frequencies.

However, this doesn't mean that human hearing isn't more sensitive to the mid-band in general. Millions of years of evolution have worked to ensure that human hearing is most sensitive to the frequencies which coincide with the vocal range.

We can identify one of hundreds of thousands of different voices very easily, even over the phone. That's an amazing ability when you think about it.

 

Yes, bass speakers tend to be large, although you can halve the volume required by using an isobaric configuration - you just need more power. In fact, use four speakers (two pairs of isobarics) and you'd only need 1/4 the volume, use eight speakers and you'd only need 1/8.
In fact it doesn't work out quite that well because the isobaric arrangement of speakers in itself uses some volume (the most space efficient solution would be a cylinder with the same internal diameter as the drive unit).

Another 'space-saving' approach is to utilize the part of the bass response below the natural roll-off of the cabinet and use equalisation. If you had enough power and drivers with sufficient excursion, you could go very small this way.

I don't really understand your comment about subwoofers, Mike. Assuming you go with two subs, is there any basic difference between a separate sub and a large speaker (think of placing a stand-mount on top of a sub to make a larger speaker). There's no intrinsic difference with subs is there?

I agree with you and look forward to hearing about your latest experiments.

Based upon my very limited listening one day to your TACT system, my ideal 7V set-up would be a top valve amp on me Nonsuch 4s and a separate TACT set up for me Little Awesomes. I'd prefer to keep your digital hanky-processing-panky away from me full-rangers though.

 

Steve,

my contention is that the majority of energy in most music is in the mid to upper bass area - say between 80hz and 200hz. Sadly, just about all commercial subwoofers are designed to crossover below 100hz, leaving the satellites to provide this energy almost unaided. It is here that I find dynamic limitations as i have mentioned before - I like big drivers working up to 500hz or so. It seems to give that sense of limitless dynamics that big speakers excel at. All IMO of course!

I'd agree to a point the real benefits for me of DSP are correction applied to the lower 4 octaves and the possibilities for time alignment and crossover transparency. Sadly I don't know of a product able to process the required information quickly enough to allow the rest to be untouched - but rest assured, it's only a matter of time.

 

Yes, I think you're right. And of course the problem with separate subs is that they can't go much above 100Hz because of the 'detecting where it's coming from' thing.

'Richard bass-nut Greene', who posts on Audio Asylum, preaches that the sub must only go up to about 60 or 80Hz (I think - from memory).

If I wasn't concerned with making a small speaker I'd probably have the bass going up to about 300-400Hz in a large floorstander. 500Hz just starts to intrude on the mids - but who's going to argue over 150Hz?

But, if I build it, will they come?

PS: Round at Doreen's last time I saw the new 15" driver. You'd love it, very serious indeed.

 

I know,i only just got round to replying though

 

All I will say is I've had great success running well designed subs up to 200hz without DSP and up to 375hz with. There is a lot more to this than our friend Richard seems to have experienced. Ask anyone who has heard Titian's setup. Remote subs crossing over at 200hz - they are 4 feet away from the main speakers!

Having said all that, you cannot do with with any commercially available active sub that I know of - although your Awesomes were sounding better to my ears at 120hz so that's Richard's hypothesis up in flames dont you think

 

No. I think there are good reasons for replacing the stand with extra cabinet volume.

Paul

 

Well, so did I. Moreover, if you've got a bigger cabinet you can always stick some extra drivers in there. However, this is mainly to do with dynamic headroom and (particularly) bass extension. Put anything with respectable bass extension at a decent volume level in a domestically normal, acoustically untreated room and you're setting yourself up for all sorts of problems with exciting room resonances and the like - a recipe for uneven bass if ever there was one. And I thought that rolling the bass off was "a lesser deficit" than having uneven bass?

I have absolutely no problem with small, limited-bandwidth, dynamically-challenged speakers, and obviously it goes without saying that it's possible to set up a terrific, beautiful-sounding stereo based on such transducers. However, if you really believe that it's anything remotely resembling "accurate", then I'd suggest that you really need to go to a live performance of something like Berlioz's Grande Messe des Morts, and during the Tuba Mirum section in the Dies Irae sequence, think long and hard about the meaning of "dynamic range" and "bass extension".

 

Was anyone advocating this in the first place?

 

Yes, that's what I was thinking when I wrote the brain"as is now today". There's no way 'the brain' decides in real time what's important as an account for why the curves are shaped like they are. However, evolution has shaped what frequencies we are most sensitive to, and this could be described as 'deciding' so long as everyone remembers this is only an analogy. (In fact, the shape of the curves more likely reflects the rough resonant characteristics of the system).

 

Its exactly this aspect of your approach to the use of subs that I found very interesting and tallies with other separate sources/opinions. In short - its about more than just bass.

 

Is this not essentially what I was suggesting?

Your Quads roll the bass off and are dynamically challenged. A problem of perspective here perhaps. Go and listen to some big ATCs...

Paul

 

Recent research over here indicates that the volume of the chamber between the two bass units counts in full. All you lose is the space taken up by the wood (or whatever) you mount the internal driver on.

 

I must admit I find that very unlikely although great if true.

Do you have a source for this research?

 

Paul was suggesting that it's "more accurate" to have smaller, more dynamically-challenged speakers with rolled-off bass than to have bigger speakers with uneven bass, I'm suggesting that actually the opposite is true - that even if your bottom octave or two are a bit lumpy, you're still getting a much better impression of what's meant to be on your CD than if they're not there at all.

Yes, it is. That's why I'm surprised you think there's a good reason to have the stand replaced with extra cabinet volume.

For crying out loud, what does that have to do with anything? My Quads do indeed in an absolute sense roll the bass off and are also dynamically challenged, but far less so than - for example - the 11Ls, which have very little perceptible 'boom' under most circumstances as they roll the bass off high enough to avoid problematic environmental modes. Does that make the 11Ls more 'accurate'? And surely in a domestic environment you'd expect "big ATCs" to excite room resonances willy-nilly, so therefore you'd expect the little ones to be more 'accurate' too?

And FWIW my perspective on these things originates in the concert hall, rather than hifi setups.