Subs

[sunnysal]

most agree that matching a sub to horn speakers is a difficult task, what works for dynamic (cone) speakers does not necessarily work for our beloved horns...sub-wise I have heard good comments about REL, some servo subs (like those from velodyne) and, of course, some horn loaded subs (from dr. edgar for example). the range you need to cover (18-45hz IMHO) requires size and power, not an easy task...regards, tony

[sfogg]

Erik,

"My concern, as mentioned before, has to do with obtaining a very close integration with the Klipschorns. "

I'm assuming you will do a DIY approach if you try this.

Here is the recipe I used for my subs with the LaScalas.

1) Sealed subwoofers with a 'Q' of about 0.5 (critically damped). Considered one of the 'fastest' or tightest designs around with best phase response. Subs of this Q are what are typically recommended for use with planars so I was hoping they would also work well with horns. Downside is they loose a little extension compared to higher Q designs though they roll off somewhat slower. -3dB point would be higher at frequency but -10dB might be lower. A sealed driver won't overload below tuning as easily as it would ported which would keep the sub from sticking out like a sore thumb if/when this happens and it distorts badly. Because of the slower rolloff on a sealed sub vs. a ported it can have useable output further below the tuning frequency then a typical ported design would.

2) Multiple drivers per subwoofer. If you agree with what PWK has said about efficiency being important and that doppler distortion is audible multiple drivers will increase efficiency, reduce distortion including doppler distortion and at the same time increase the maximum output available. Of course multiple drivers increases cost and box size required (unless you do compound loaded drivers but then you don't gain the output benefits) On a cost benefit scale biggest benefit is from going from 1 driver to 2 drivers per cabinet. To gain the same benefit again you need to go from 2 drivers to 4... then 4 to 8...etc..etc..

3) Good crossovers. Fourth order at least to keep the interaction between the subs and mains low.

4) Build a solid box. It won't do any good if the box is resonating and adding distortion to your playback.

5) If you can not located the subs roughly the same acoustic distance from the listening position to the mains (keep in mind the delay through the horn) then have some way of delaying the mains (or the subs) to get them time aligned.

6) Plan for stereo subwoofers. Yes bass in 'non-directional' below around 80hz however there is more to the perception of bass then just being able to point to where it is coming from. Stereo bass (in the sense of stereo subwoofers AND bass actually recorded in stereo... in many cases it is mono on the recording) can impart a sense of spaciousness to the playback that mono bass just won't do. It can also sound more like how we hear bass in a hall compared to a home environment and not having a 'in your head' quality like mono bass does. You also get reduced distortion and doppler distortion again with multiple subs compared to one.

Shawn

[sfogg]

Forgot one other one....

If possible plan for some EQ to deal with room resonances. This means parametric EQ and a way of measuring the time domain response of the system to look for the areas in the subwoofers response that 'ring' the most. You then use the parametric (and it needs to have very fine controls... like 1hz range) to attack those modes.

Shawn

[sunnysal]

shawn, can you post links to plans for subs like you describe? thanks, tony

[Erik Mandaville]

"It is NOT subjective at all. Double blind listening tests show that people prefer tubes over solid-state"

I'm sorry, I disagree. It couldn't more subjective, and there are many people who prefer solid state to tubes. There are also many who prefer tubes to solid state.

The double blind test to which you refer must have been one of enormous scale and scope. To say that all prefer tubes to solid state does not do much for those on this forum that are very happy with their transistor based amplifiers.

I have been using tubes for many years, and I enjoy their sound a great deal. However, it would be an inaccuracy on my part to say the tubes are necessarily 'better' or worse than solid state amplification.

It all remains, in my opinion, entirely subjective.

I appreciate your input.

Erik

[Erik Mandaville]

Shawn:

Thanks for a constructive reply that focused on possible how-to's of subwoofer implementation rather than the passing of judgement on whether it is/was a good idea.

I suspect I should tell those who have emailed me to say that they are very happy with how a high quality sub sounds in their systems....with Klipschorns...that they are wrong and don't know what they are talking about.

In any event, say that we did make an investment in a good sub (I'm thinking of possibly an SVS sometime), and with a little work and tweaking here and there, we obtained a very balanced and even response -- using my home-built-and modified Horus 2A3 amplifiers as the stereo amps (these are in fact tube amps, by the way.)

Would I then be told I was 'wrong' in liking the resulting sound, and the fact that I was enjoying what I heard was simply the result of a lack of experience and or understanding concerning the 'proper' use of horn speakers and low power, single ended triode amplifiers?

curious,

Erik

[sfogg]

Erik,

" I'm sorry, I disagree. It couldn't more subjective, and there are many people who prefer solid state to tubes. There are also many who prefer tubes to solid state."

Well said. It is worth pointing out that DBT are *not* preference tests. All the can prove is audibility of a difference. From there it is up to the user to decide which they prefer.

You may be able to find trends with DBTs but anyone that thinks they will automatically tell you what persons XYZ preference is is mistaken.

Shawn

[sfogg]

Tony,

"can you post links to plans for subs like you describe? "

The 'Q' of the subwoofer will depend upon the driver chosen and the cabinet size it is used in.

In my case I used JBL Sub1500 drivers (used by Revel in their Ultima Sub15). The cabinets are about 6 cubic feet internally. Dimensions are the roughly 35" tall, 24" deep and 16" wide... sized to match my LaScalas basically.

Because I was busy building the room these were going in I had John at Stryke Audio build the cabinets for me. He did a great job and at very reasonable cost. Nice bracing and double thickness front baffle. He would be able to duplicate them for others since they were done on a CNC router. Because these were going into a theater room and will eventually not be seen I just went with a basic black finish on them. I'm sort of kicking myself for not having them built out of baltic birch as I could have then finished them to match the Las but if I really wanted to I could always veneer these later on.

From there I stuffed each cabinet with 5lbs of Acousta-Stuf and installed the drivers and enjoyed.

If you want pictures of them just let me know.

Shawn

[Erik Mandaville]

I guess I think that, even if those in a double-blind test did consistently prefer sound 'A' to sound 'B,' the very act of choosing one over the other is an example of subjectivity -- and is concerned with only the population within the test situation, itself. It is completely impotent, as far as I'm concerned, if the same test were then used as the only criteria for assessing the preferences for tubes or transistors on a global scale -- which is what the post above implied. What test was this, what people, and how can one single test of this type be the means of judging the entire audio community at large? If everyone now prefers tubes, why aren't tube-based amps the only kind of amplifier manufactured?

My effort with this post was so elementary and very simple. It was not an effort to ONCE AGAIN kick the already horribly flogged valve v.s. transistor/power debate.

I have my bacteria-sized tube amp and home-made preamp warming up, I want to go listen to some music -- and give a little Thanks for my wonderful wife and family, my friends, the food we have in abundance, and for the comparative peace we are very fortunate to enjoy.

[seti]

----------------

On 11/23/2004 1:59:55 PM Erik Mandaville wrote:

If everyone now prefers tubes, why aren't tube-based amps the only kind of amplifier manufactured?

----------------

Price? The reason for switching in the beginning.

I have a friend with good solid state amp with his b&w's and they sound great very very clear. Of course this sounds even better when he fires up his TT and tube based phono pre. I would own some solid state gear as well if I only had enough cash to afford all the gear I want : (

Perhaps I'll put some change buckets around town with signs that read pleas donate to help find a cure to monatarydeficiousaudiopilepsychosisadictus

[Daddy Dee]

Shawn,

Interesting design. I'd sure like to see some pics. Thanks.

[sfogg]

Erik,

"I guess I think that, even if those in a double-blind test did consistently prefer sound 'A' to sound 'B,' the very act of choosing one over the other is an example of subjectivity --"

That is still subjective, I agree.

I was just pointing out that the point of a double blind ABX test really isn't to pick A over B. The point is to identify if X is A or is B. 'X' is randomly chosen to be either A or B.

For example say you have one listener that claims xyz tube amp is 100 times better then abc SS amp.

Some might question that claim. If that listener is given a double blind level matched ABX test and identifies the identity of 'X' only 50% of the time (the same odds that would be expected for just guessing) that would suggest the listener couldn't tell the two amps apart when they don't know which they were listening to. Which then makes the earlier claims dubious. Note: That doesn't mean someone else might not be able to tell the two apart... just that this person failed to on this test.

Or on the flip side if they scored 99 out of a 100 trials correct it certainly suggests that there are audible differences between the two devices under test.

IOW, those that claim an ABX test 'prove' a tube amp is preferable over a SS amp don't really understand what an ABX test shows.

Certainly tube vs. SS has been ABX tested and the results of some of those tests are very interesting. For example in one comparison of a tube unit and a SS unit the two amps were indistinguishable from each other... IOW they sounded the same. However in another test (with the exact same two amps) they were very obviously different sounding based on the scores.

How could that be?

Because different speakers were used in each test. In one case the speakers were impedance compensated and a relatively benign load. In the other the speakers were very reactive.

Another example would be in 'conditioning caps.' A person might claim they make major differences in sound. Someone may say 'prove it' and an ABX test would allow them to do that. If they can reliabily ID 'X' then they are in fact hearing something different between the 'conditioned' cap and the unconditioned one. If they can't...well......

Shawn

[sfogg]

Few pictures...

From the front:

Cabinet from the side:

In the system:

Shawn

[Erik Mandaville]

Very good examples, Shawn. I was also in agreement with your initial response regarding this sort of testing.

Nicely built boxes, with special attention given to the routing and internal bracing. These must be really very good!

Bob Crites has also recently shown some pretty nice boxes, combining the K-horn/La Scala top over a large bass reflex cab (if my memory is right on that).

Good luck with the sale of that amp!

Erik

[dubai2000]

This forum often makes me curious to try something new. Well, I happen to have an external crossover (dbx) which is currently not used. So why not use it to connect the sub? Couldn't it be 'superior' to what SVS includes in their units? Nothing ventured, nothing gained. So now I have been using this....yes, between GG and my new DRD45 amps (more on those later) and it sounds interesting. Bass seems to be a bit tidier/everything else perhaps(!) a tad more open, but because there are a few more knobs to play with on the crossover, it's too early to pass a more thorough judgement. Anyway, just another toy to play with .

Wolfram

[3dzapper]

Shawn's picture does not do justice to his HT room. It is an excellent design. Aurally isolated and though small, presents an image of a small auditorium. Here is a lightened image for all to drool over:

As you can see the front is wall to wall modded Lascalas and subwoffer. The walls and ceiling are lined with sound deadining foam. A hand clap is pure, no after ring.

Rick

[sfogg]

Thanks Rick.

It is a small room (had to work with what I had available) but it 'plays big' and because of the acoustic treatments doesn't really sound like a small room. If you ever want a longer demo just let me know.

How is the LaScala working out for you?

Shawn

[3dzapper]

"How is the LaScala working out for you?"

Great! I built up that other ALk for it and just today I recieved a batch of highly figured Black walnut veneer for it to match my Khorns. I'll tackle that project after hunting season.

Rick