Gravity Well Of A DarkStar

Wind Chaser · « **Reply #680 on:** 24 May 2006, 11:07 pm »

Quote from: JohninCR

My better OB is with a Fostex FE108eSigma using the woofer of the Hawthorne Iris in my OB-RLH. It gives me sufficient extension on both ends, a much flatter overall response, and a better, more detailed midrange. The problem is the woofer is used too high and the single point source is sacrificed, so with the right music the B200 OB-RLH is tops.

John,

I thought you also acquired a pair of HA Augies? While I haven't heard the FE108e Sigma, I am familiar with its predecessor the FE108 Sigma. The earlier version of the 108 has an audible rising HF response that can be quite irritating. "A Salty Dog" by Sarah Brightman at loud volumes especially comes to mind, bordering on pain.

If I read between the lines, it seems you are suggesting that the FE108e Sigma has better bass response than the B200? Or is just that the Fostex is characteristically more linear and therefore easy to integrate?

John - Chasing The Wind

mcgsxr · « **Reply #681 on:** 24 May 2006, 11:28 pm »

Quote

Dave at Planet 10 has spent some time listening to the B200 with a phase plug

I bought my set of b200 off of Dave, all those months back, he truly is a friend in this business, and if he has concocted a way to improve the sound of this driver, I will absolutely be supportive of that, including having my own done.

I agree with Richard, if you are reading all this, and thinking that someone will conjure up the perfect implementation for you, I think you need to revisit that old idea that " the journey is the destination", and pony up $300, and have some fun with us!

scottw · « **Reply #682 on:** 25 May 2006, 02:25 am »

Quote

Dave at Planet 10 has spent some time listening to the B200 with a phase plug

Was Dave able to measure the frequency response before and after adding the phase plugs?

I've almost got my nerve up to do the dustcapectomy.

Scott

Dmason · « **Reply #683 on:** 25 May 2006, 02:54 am »

It would be informative to know what kind of implement Dave used for the dustcap-ectomy. I know this manila and hemp stuff is unbelievably Tuff As Hell.

Maybe Jiffyboob could send some dermotomes up to Victoria if Dave is going to do this regularly

Russell Dawkins · « **Reply #684 on:** 25 May 2006, 04:41 am »

Here's a little idea I had which might work for those wanting curved baffles - either simple or compound curves.

I was in an antique furniture store - I believe the sign said "We buy junk and sell antiques" - when I spied an ornamental chair where the bulk of it was made of papier maché. It was about 5/8ths of an inch thick and passed the knuckle rap test well. At the time it occurred to me that this really could work as a simple (and non-toxic) way of making any baffle shape your imagination could come up with.

I would try a shape like a long shield first, with the convex side toward the listener. The flat area for the mounting of the driver(s) would be designed in from the start.
The curve would raise the resonant frequencies much higher than they would be on a flat panel by increasing stiffness.
Two weekend NY Times should do one baffle!

-Richard- · « **Reply #685 on:** 25 May 2006, 06:25 am »

Hi JohninCR,

I am taking your suggestion about using a Fostex 108e Sigma very seriously.
I will try it!!!! Some time in the near future. I deeply appreciate your sharing
your insights with me and everyone who reads these posts...I love your idea of
using foam core board...or its equivalent...as a quick way of creating a "baffle sketch"...
a sculptural model for a baffle that is quick and highly informative...you certainly think
like an artist John...that was a wonderful thing to share with all of us as well...very very
helpful...and inspiring!!!! Thanks John!!!

Hi Russel,

Another great idea...paper mache is a terrific idea for creating curved or amorphous
shapes...how ingenious!!!! I am very very tempted to put that idea to the test very
soon...If you could find a "form" that replicates the desired shape it could be used
as a template to form the paper mache to...here in Ojai things are drying out...
that would make the actual drying time a snap...Thanks so much Russel...

Warm Regards -Richard-

Dmason · « **Reply #686 on:** 25 May 2006, 03:16 pm »

John,

My best professors, the ones you remember always came off as cantankerous. Whatever that word means. Your studies and designs have been a constant source of amazement to me. This stuff gets me off, and you are the trailblazer. I love all the distillation and good thought going on here.

I also love the resonant qualities of Spruce, especially when it is found in the bed of a grand piano, but right the way through the orchestra, Spruce everywhere.... My next baffles are going to be made of Spruce. I have wanted to see what type of resonances might come from that, that lend a musical instrument quality to the sound. It makes me think of a wideband driver that can dig abit deeper on OB, the Supravox 215. This driver on a spruce baffle might actually be a very musically resonant combination, which is designed to get down to the low 50's, and exhibit similar bandwidth to the average "minimonitor." I open the table to commentary.

Wind Chaser · « **Reply #687 on:** 25 May 2006, 04:15 pm »

Quote from: JohninCR

if Richard put a broken in 108 in place of his top B200 on his dual B200 setup, he'd probably be thanking me for the idea until the cows came home. As good as the B200 is, the 108eSigma outclasses it IMHO by a wide margin from 200hz on up, except sensitivity from 900hz up.

John,

Are you suggesting Richard should mount the 108 on his flat baffle without a RLH? I like this idea as the 108 is smaller and it doesn't cost as much as the B200. If indeed the 108 is even better than the B200, I will have phase plugs put on them too, as Dave told me was phase plugs have even a more profound effect on Fostex drivers.

Ed Schilling and most of his disciples made a transition from the 108 to the 126. I haven't heard either of these two drivers or compared the specs, but from what I understand the 126 is more extended and more efficient. How it sounds and whether or not it would work in OB is another question.

John Busy Wind Chasing

-Richard- · « **Reply #688 on:** 25 May 2006, 04:24 pm »

I am perfectly comfortable with the idea of using the Fostex 108e Sigma or the
Supravox 215 for the ongoing experimentations into the possibilities of Open Baffle
designs...and Spruce may indeed have a musical "personality" that it can favorably
impart to the sonic signature of whatever drivers we are using...

I love the open-ended experimentation here...the offerings for new possibilities...
it is exciting...because it is so easy to implement and think about...

This thread has taken a turn from what some contributors assumed was its original
premise...it has shaken loose some of the earlier frustrated readers who could not
keep up with the mercurial nature of an open-ended flow of design ideas...
it is a nice change that suits my nature perfectly...ahhhhh...I love the space that is
now being created...a free flow of ideas penetrating the possibilities...without the usual
concretizing of fixed positions which only gathers mold and a rancid posturing...

Warm Regards -Richard-

Brad · « **Reply #689 on:** 25 May 2006, 06:04 pm »

I was reading about the bamboo material used by http://www.nomad-audio.com/

Seems like a 3/4" sheet of that used to make the baffle would be both strong and very nice to look at.......

I think I'll start playing with just some plywood, but when I figure out the final design that works best in my room, I'll use the bamboo.

mcgsxr · « **Reply #690 on:** 25 May 2006, 06:50 pm »

I would be very interested to source a Bamboo distributor on my side of the border... I can only imagine the price to ship a 4x8 of that stuff at 3/4 thickness...

Besides, it is only natural to want to put the hemp driver in a grass panel!

opnly bafld · « **Reply #691 on:** 25 May 2006, 11:46 pm »

Gravity Well of a Dark Star is celebrating its 1st year anniversary today.

With almost 50,000 views.

Now back to the music.

Lin

corloc · « **Reply #692 on:** 26 May 2006, 03:51 am »

Go away for a couple of weeks and the thread go nuts. I like th idea of useing 2 b200's. Ive been searching for a 15" that I would be happy with tied passiveing to the B200. The fe108ez is a nice idea too.

When I get home i'm going to put my Tang Band W4-1320's and some coils onto my baffles. Or my Fe206e's Hmm.... They wll not sound as nice as the other suggestions, but the experiment should alieve or confirm if two drivers will bother me with point source.

opnly bafld · « **Reply #693 on:** 26 May 2006, 04:58 pm »

I must be almost deaf. ( I am 42 and according to tests still have pretty good hearing, although the tests were not DB)
Try as I might last night, I could not hear a difference between 2 B200s and 1, except of course the extra weight and bloom in the lower frequencies.
The soundstage and everything else all seemed the same.
I have the ability to mute the lower driver on the fly.
Will continue to evaluate.

I have come to the conclusion that, (keep in mind the first statement) the OB presentation really makes a difference, for the better, in what I hear vs. what was heard by those recording.
I have some music that for years I have not liked some of the songs, (listening on many speakers) even skipping some each time I played the disc.
But listening to these same songs with OBs, I think to myself, so thats why they recorded this.
Some examples are Dave Holland's Big Band. (13 instruments)
I like most of the songs on the two CDs that I have, but a few always sounded to me as if the music sheets got mixed up and they were on different pages.
And one CD I have of songs with various singers, there is a song done a cappella with all female singers, I could not hit the skip button fast enough with that one.
With OBs I can actually enjoy them and I feel like I am hearing them closer to how they sounded live, they make more sense to me as a recording.
FWIW some thoughts,
Lin

opnly bafld · « **Reply #694 on:** 26 May 2006, 10:15 pm »

John,
I will try that.
Thanks,
Lin

opnly bafld · « **Reply #695 on:** 28 May 2006, 11:16 pm »

JohninCR,

I used the right channel signal for both baffles.
Left side both drivers, right side only top driver.
I balanced back and forth, muting the preamp for the bottom drivers when listening to the right baffle.
Still I could not hear a difference in any negative way with 2 drivers.

A couple of times when I first started I had the lower driver on the left baffle playing with the upper driver on the right baffle.

Even then I only noticed a little widening of the sound.
Instead of the sound coming directly from the right side driver it sounded as if it was coming from about 6" or so from one side of the driver to the other side.

Another side point, I have noticed that if I just listen to the top pair of drivers for awhile it sounds pretty good, just a little thin in the lower frequencies.
But switching back and forth more rapidly between one driver and two, one alone starts to sound very thin.
Lin

scorpion · « **Reply #696 on:** 28 May 2006, 11:34 pm »

Inspired by this thread I have done an experiment with my Ciare CH250-baffles.
They measure in all 40 x 24 inches including two wings, 7 and 5 inches respectively. As Dmason pointed out the Ciare's treble shouting has to be tamed. This is done with two series resonant band-stop filters at 2.5 and 5 khz. All works very well with my S5-Tube Amp. Thus there are no parts in the signal path between the amp and the loudspeaker. There are 11.2 inches from the baffle upper edge to the centre of the element. The baffles are about 8 feet apart.

Now I kept the right speaker as it is. Turned the left speaker upside down, removed the bandstop filters and played it just via a low-pass 6 db filter @ 150 Hz. I played with both speakers but in mono.

I can now see the point of putting two identical drivers on the same baffle, like some of you have done. The sound is "fuller", bass more pronounced. The right hand speaker sounded "thin" alone compared to when both were playing.

But, most amazing, the single point source was not destroyed even with 8 feet between the speakers when I was listening in my normal stereo seat. Alas, very low bass-notes were placed more towards the left speaker otherwise I was just hearing the right hand speaker.

opnly bafld · « **Reply #697 on:** 28 May 2006, 11:52 pm »

scorpion,
Glad to hear about your experiences.
Keep us posted as to what you do next.
The OB sound is awsome, is it not?

Lin

opnly bafld · « **Reply #698 on:** 29 May 2006, 02:43 am »

John,
I listened to one speaker at a time.
I wanted to compare oranges to oranges, (or apples to apples) that is why I ran only the right channel signal.
The music always sounded like it was coming from the top driver.
I am sure that if I turned the volume waaay up on the lower driver it would pull the sound down.
But at the level that sounds balanced to me, the soundstage height stayed the same.
I could not percieve any sound originating from the bottom driver or the effect that would have.
Lin

scorpion · « **Reply #699 on:** 29 May 2006, 10:21 pm »

Lin,

Seems that we have had about the same experience with double drivers.
I do think that the lower unit should be restricted to about 100 Hz so as not to add to much to midrange. You do not hear it, but it is there. In fact, just listening to the lower speaker reveals that it is pouring out sound quite a bit up in frequency with a 6 db crossover.

Question is if identical speaker doubling is necessary or if one could have the same type of bass- (and a little bit more) reinforcement just by adding a cheap woofer below. Look for instance at the Parts Express unit: GOLDWOOD GW-215/40/8 15" OEM WOOFER 40oz.

Double the units is of course very natural. You don't have to bother about speaker efficiency. I would like to have some more affirmative indication about the B200's performance in the bass region when playing in an open baffle of at least 40 x 24 inches size.

But otherwise you are right, OBs are the way to go. For the last 30 years or so I have lived with "Maggies". First MG-II and since 1991 MG 1.5. These are very "civilized" and very good speakers. In comparison the Ciares are not that smooth but more dynamic and absolutly more fun !

/Erling