Multiple Small Subs - Geddes Approach

[gedlee]

Originally posted by mat02ah

Again: I didn't want this discussion. I just wanted to know whether a HP is needed to make the principle work. It's not - thanks for your answer.

Regards
Thomas

No a HP is not required, its not even desirable, but sometimes, as in your case, it is necessary.

"because the "hands down better" is not very substantiated to me from looking at the mere two plots you present "

This is DIY, substantiation of ones opinion is not only not required it is very seldom done. I show the "most" significant data for my speakers. I would like to show the MAX SPL data, but I don't think that %THD is very meaningful. I view thermal compression as probably the more limiting factor. I think that the world needs a set of data that is more meaningful than what we have - I think that we'd all agree with that. What I am not willing to do is show data that I don't believe in just because others do. That wouldn't make much sense to me.

The data that I show correlates well with the subjective opinions that are posted.

At some point I'd like to show a good thermal test, I, and other, are working on this now. I think that the current thermal tests are lacking, and MaxSPL based on THD is just hard to accept as a "good test".

Does K&H show polar data?

[mat02ah]

Originally posted by gedlee
No a HP is not required, its not even desirable, but sometimes, as in your case, it is necessary.

If I add 100Hz/2nd order HP I will gain max. SPL and the LF response will be slightly worse than the Nathans' response (I guess the max. SPL will still be more than slightly worse ...). And since you say a HP is not desirable I guess there will be a tradeoff between blending the subs to the mains and max. SPL. I also guess that 2nd order will be the best compromise since 1st order won't help much for the max. SPL and 4th order is too steep for the blending.

Originally posted by gedlee
Does K&H show polar data?

They do. Vertical and horizontal.

Regards,
Thomas

[markus76]

Originally posted by gedlee
Does K&H show polar data?

Yes, they do. Select one of their products and then click "Measurements, e.g.
http://www.klein-hummel.com/klein-hu...-monitors_O300

[gedlee]

Well I applaud the data that they show, however, the polars on the 300 are not very good. Certainly not competitive with an Abbey. Thanks for the link. I know that K&H have a good reputation and make a great product.

mat02ah

I would think that a first order HP would be a major improvment. From ease of implimentation its a no-brainer (the amp is internal, but you might still get away with an RC at the input). If you look at how much even a 1st order HP limites cone excursion its dramatic. Cone excursion is a linear limitation and filters are usually done in dB. A few dB is a lot of excursion reduction.

[Russell Dawkins]

There's not a trace of doubt in my mind that any of Dr Geddes speakers would trounce these 0300s in terms of dynamic headroom.
As I said earlier my audition of these, coupled with numerous informed comments in mastering forums, suggest that "translation" (to the world at large) is a particular strength, and this is something that is hard to come by and something for which mixing/mastering engineers are always on the lookout.

Here is a significant comment re: real world dynamic capability with the 0800 sub (which is more about increased dynamic capability than extended LF, thanks entirely to the 90Hz high pass to the 0300s).
This came from a composer/engineer responsible for many of the biggest budget movie trailers of the last 4 years:
"We had the 0300 + 0800 up at Warner's Scoring Stage. It's a world class control room. We never switched over to the soffit monitors, but when we left I was talking to a couple of people who thought we were listening to the main soffits the whole time. You can throw some serious bottom at the 0800 and it won't flinch."

When I heard them, I would say the most unusual truth of timbre was heard in the 100 - 400 Hz region (at a guess). I think a key to the low levels of distortion I heard (at realistic levels) around 1.5 kHz (on a Bulgarian choir) is the use of the 3" midrange dome from 650Hz-3.3kHz.
K+H are no neophytes - they put the world's first powered studio monitor on the market in 1967 - a three way - and have been methodically refining the design ever since.
As I said, I think these will serve admirably as a reference while investigating alternatives, of which the Abbey is the most appealing to me.

[mat02ah]

Originally posted by gedlee
... the polars on the 300 are not very good. Certainly not competitive with an Abbey.

Is the Abbey usable as near-field monitor in 1m distance? And by the way: If I could afford an appartment in Heidelberg with a living room the size you seem to be thinking of, I'd have different speakers ...

Originally posted by gedlee I would think that a first order HP would be a major improvment. From ease of implimentation its a no-brainer (the amp is internal, but you might still get away with an RC at the input). If you look at how much even a 1st order HP limites cone excursion its dramatic. Cone excursion is a linear limitation and filters are usually done in dB. A few dB is a lot of excursion reduction.

That's interesting because it tells me that you think that the blending is more important than the max. SPL (I guess SPL-wise I'm a lost case for you ...).

Regards,

Thomas

[gedlee]

mat02ah

Believe me I understand your situation completely. It's not so uncommon, even here in La-La land. I have been to a lot of German homes, etc. so I know the issues.

What I make now would not be very good nearfield monitors. They are not designed for that. But the next version probably would as it will be much smaller. I am going to target the exact same size as an Yamaha NS-10 as I think that I can make a much better speaker than that one at a much lower cost.

I am a big movie fan and movies just cry out for SPL! SPL!! They are mixed so that the sound track elicites emotion. Quite frankly thats my main interest because it is so impressive when done right. I haven't been to a commercial thaeater in almost three years anly only twice in the last seven. I really don't like movie theaters anymore - they are so bad. But I have seen far more movies than anyone else that I know.

If you want the impact of the film that the producer intended then you have to have SPL and lots of it. If all you listen to is music at a lower level, thats a competely different thing.

Fit the design to the usage.

[peterbrorsson]

Fit the design to the usage.

That's the most reasonable post for a long time in this thread.
I was living in Poland for 1.5 year in a 12 sqm room with a pair of Genelec 1030A. Created more noise(good) than the neighbors could stand.
In my present ~55sqm room they are enough also, but without the #$& kicking Rock"n"Roll factor. But hey, who's to blame. Me or the speakers?

Peter

[gedlee]

No question - my application is specific and high SPL is a need. That's why I am looking at the smaller system so seriously because I think that I can get pretty good sound quality but at a whole lot less SPL and a huge cost reduction to boot.

[terry j]

phase hs been mentioned as a factor to get right.

First off, can we get a quick defn of phase as it's used here??and more importantly, HOW do we get a measurement of phase and when do we know it's correct. Measurements are an important part of the procedure here, so I'm curious to learn how to measure this aspect.

Why? cause I too have mucked about a bit with subs etc using the dcx 2496 (which has phase adjustment), 1) could not get a method to measure it (I'm dumb ) and two) doing it by ear...well couldn't really hear much difference anyway (I'm deaf as well )

but hay, if it can be done properly then why not and if done properly I may be able to hear it.