Gravity Well Of A DarkStar

nodiak · « **Reply #840 on:** 11 Jul 2006, 04:19 pm »

JLM, you missed the distinct point of my post. It was meant as a reaching out to anyone who might share a curiosity I have about the differences in 2 approaches of modifying the frequency response of the B200's in ob. That's it. Not an off hand pondering, or an attempt at the #1 supreme system. Just another worthy variation on the theme. True about small amps not being able to push the (approx. 4db) lower effiency, obviously that person wouldn't be into the idea, but haven't you noticed mention of 10 watt Charlize, Sig 30, 50 watt gc, etc...? Also, maybe you mentioned mltl from an assumption that that is how I used the 167 with bsc circuit. No, it was on an ob with 12" bass bins below (ala cheap approach to Basszilla), sorry I should have mentioned that. Feels like you diluted and diverted my question to anyone who may share my curiosity. I'm fine if no one does, but to me it's a worthy idea to check out, just seeking similar adventurers. I think a thread with 900+ responses has room for this idea.

**

With all the work and play going on modifying the frequency response of the B200's on ob I'm curious if any have checked out the response differences in the current 1.5 method and using a bsc circuit on a single B200. Especially curious about difference in balance of high frequency levels between the 2 approaches.
My apologies for not doing it myself as I no longer have B200's (maybe again later - I'm open to a little admonishment, just a little please) and summer activities have taken over from audio interests for me, but this thread cannot be ignored! The frequency response difference is just something I would explore if I was in a position to, as it gives other choices.
If anyone is curious, and has the parts available, I would guess a ~ 1.5mH inductor paralled with a ~ 4 ohm resistor, and this combo in series with the positive lead on a single B200, would bring the midrange down close to the bass and treble levels to give a more even frequency response. Be cool to try other LR values too. Might be enough bass for some nearfield/small room situations (not me either Mark of Canadia

). Also might bring the efficiency low enough to mate with a ~ 90 spl bass driver for a one amp system instead of powered sub approach (= less $). JLM mentioned Augies, and there are lots of others smaller and larger.
Sorry again for not doing it myself, it looks like awhile before I would, maybe some one else is curious about this too. OF COURSE I realize some my not like this idea for various reasons, it isn't a challenge of any kind, just another idea in the pot that might interest someone in this big wide world of ob exploration.
I only bring this up since the use of a coil on a 2nd B200 is accepted now, so maybe some are also interested in using a smaller value coil on a single B200 = less dcr, less $...

Don

mcgsxr · « **Reply #841 on:** 11 Jul 2006, 07:55 pm »

Nodiak is absolutely right, I doubt that application of the circuit would do it for me, with my bass heavy musical selections.

But that silly H baffle, Rockford Fosgate subwoofer I built is perfect. Sounding... as for the level of finish, well I can live with it, and since the basement is, as yet, unfinished, the sub might as well match!

Heck, my whole system is raw mdf at this point, with OB mains, and OB sub!

Great idea though, for a smaller room, with more sensible needs!

nodiak · « **Reply #842 on:** 11 Jul 2006, 10:54 pm »

John, it's an old tried and true method for single drivers. Bass issue is understood, I mentioned the lower eff. would more easily combine with bass driver of ~ same eff/spl.
I only brought it up as another possibility as I hadn't seen it in the thread, might work for some. Now that the thread is allowing passive components might as well give comment to the variety that have been used.

JLM · « **Reply #843 on:** 12 Jul 2006, 11:07 am »

Don,

I didn't mean to side track from your point, it has merit. I just wanted to point out that OB would need more compensation than a cabinet style speaker. I believe back about 500 posts ago that some had tried digital EQ, but as JohnCR points out the OB runs out of bass steam.

BTW there's recent post on the Decware forums from a "new" guy who uses four 18 inch woofers, Lowther, super tweeter, and bi-amping in a single OB. Serious stuff! And he slams the B200 as quite veiled compared to the Lowther.

nodiak · « **Reply #844 on:** 12 Jul 2006, 05:34 pm »

OB's have less bass, think we're all onto that.
With the 1.5's it seems things have travelled to ways of dealing with B200's lesser bass response on ob. The bsc idea is related in that it also changes the balance between bass, mids, and treble of the driver. It's possible to bring the mids down to ~ the same level as the bass, just as the 1.5 brings the bass up to mids. So yes you have a less eff. speaker and need more watts, that's given. What is different in FR of single driver with bsc is the treble is more eff. than with a 1.5 approach. Might be useful or at least interesting to someone, else. More treble, costs less, might taste great to someone. Maybe being less filling it won't satisfy some...
Just curious if anyone has or is interested in following that approach. Not judging it as better, just another stone thrown into the soup. I used the bsc on a different driver on ob, and coupled with bass drivers it worked for a passive one amp system. Impure but functional. That was last year, I'll see if I can get to it again with the 8" hemps which are the only single drivers I have now. Could be interesting, just right now I'm involved in other things, my bad.
The 1.5 (2.5 with tweeter) idea has been around a while, even using dual voice coil midbass drivers like the 80's Focals, tho they offer about half the extra eff. from one vc when it's rolled off for bass boost vs. using another driver. I still have a pair of 80's Focal kevlar 7" dvc, and should find time to follow through on my own curiosity by using it on ob.
Didn't mean to interupt the flow here guys. I'll get off my arse at some point and try my own ideas. But I bet someone else is curious about this too.
Don

opnly bafld · « **Reply #845 on:** 13 Jul 2006, 01:21 am »

Don,
Your posts are much appreciated

and no flow has been interupted.
I think I might try this, it will be cheap and easy.
It would be interesting to find out if it has any effect on the gravitational pull.

PS some OBs have as much bass as a lot of box speakers I have heard.

Lin

nodiak · « **Reply #846 on:** 13 Jul 2006, 02:27 am »

Hi Lin, thanks, wouldn't want to get in the way of a Dark Star

. Interestingly enough the FE107e's you bought from me worked pretty well without any bsc on them, compared to the FE167e's which I felt required Bob Brines bsc to even out the response. I had both at same time and enjoyed comparing them on ob with the same bass drivers below.
I agree the B200's on ob have more bass than alot of smaller boxed 2 ways.
I need to live near one of you guys, can't afford to keep all the drivers I'm interested in around. i basically buy and try some drivers that intrigue me, then sell some complete as systems locally to afford to try others. Maybe next winter I'll have a few favorites worked out.
Don

Dmason · « **Reply #847 on:** 13 Jul 2006, 02:30 am »

The only dumb question is the one un-asked.

Absolutely nothing happens in this world without experimentation. And absolutely less than nothing happens with a room full of theoreticians. There is no "norm," here, to deviate from, except open baffle alignments, perhaps. Mass-loaded transmission lines, for example, would not qualify for discussion here.

Personally I like where Don's brain is headed on this one, I may try this soon.... and Lin is right: in a smaller room, the bass coming off one B200/OB is better, and mo bass-er than most little minimonitors. Actually quite abit better. Enough to add some foundation. The Signature 30 incidently, adds some more cojones to the mix, no doubt, so if you are thinking, "bass like minimonitors?

" think, like Dynaudio 1.3 minimonitors, because the more power you throw into it, and the B200 can sink unearthly amounts, the more bass you get. It makes me wonder what those Supravox 215 with BIG Xmax, paired with a 100+ Class A high current amp would sound like. Martin King recently made his point that his Rx done up right, for SS amps offered "more" than tube amps, and that the greatest gains were made rendering the environment acoustically optimal. Just thinking aloud here.

nodiak · « **Reply #848 on:** 13 Jul 2006, 03:05 am »

It's just another tool. Might work for some situations - rooms, music tastes, equipment, budget. Maybe a smaller niche than other ideas, who knows till it's tried?

oldtimer · « **Reply #849 on:** 13 Jul 2006, 11:13 am »

Don, Your suggestion has merit, and for those of us that may want to experiment with it , could bring some nice results. I am going to try this and see what I think of it. Until you try something, you just dont know.

Nigel

PS, I have no idea where the oldtimer came from, not that it is not accurate, but it is bizzare.

nodiak · « **Reply #850 on:** 13 Jul 2006, 04:33 pm »

Nigel, I'll get around to trying it on the 8" hemps too. I also have phase plugs for them from planet10. Am interested in how the phase plugs work for folks on B200's also.
Don

LarryC · « **Reply #851 on:** 14 Jul 2006, 03:32 am »

Quote from: nodiak on 13 Jul 2006, 03:05 am

It's just another tool. Might work for some situations - rooms, music tastes, equipment, budget. Maybe a smaller niche than other ideas, who knows till it's tried?
...If anyone is curious, and has the parts available, I would guess a ~ 1.5mH inductor paralled with a ~ 4 ohm resistor, and this combo in series with the positive lead on a single B200, would bring the midrange down close to the bass and treble levels to give a more even frequency response.

Don,

Tried it and I Like It!

Thanks for the MJK reference also, it helped. Here’s a link if others are interested:
http://www.quarter-wave.com/General/BSC_Sizing.pdf

I tried 3,4, & 5 ohm resistors. The 5 did it. Those were the only resistors I had, but I'm sticking with the 5 ohm for now because of what I am hearing. Anxious to hear what others find when they try it.

I saw/heard Jane Monheit last year at a small Jazz club a couple a blocks from my house. She had a terrfic bass player who has now returned to my living room with the BSC circuit in place. Jane's Honeysuckle Rose sounds fantastic now that the bass player is back.

photos:
http://www.websiteonline.net/b200/bsc1.jpg
http://www.websiteonline.net/b200/bsc2.jpg

Quote from: Dmason on 13 Jul 2006, 02:30 am

Absolutely nothing happens in this world without experimentation.

Cole Porter: ‘Experiment’ http://www.websiteonline.net/exp/experiment.mp3

Before you leave these portals
To meet less fortunate mortals,
There's just one final message
I would give to you.
You all have learned reliance
On the sacred teachings of science,
So I hope, through life, you never will decline
In spite of philistine
Definace
To do what all good scientists do.

Experiment.
Make it your motto day and night.
Experiment
And it will lead you to the light.
The apple on the top of the tree
Is never too high to achieve,
So take an example from Eve,
Experiment.
Be curious,
Though interfering friends may frown.
Get furious
At each attempt to hold you down.
If this advice you always employ
The future can offer you infinite joy
And merriment,
Experiment
And you'll see

----------
http://www.websiteonline.net/exp/honeysuckle.mp3

LarryC

nodiak · « **Reply #852 on:** 14 Jul 2006, 05:24 am »

That's great LarryC ! Another possibility, always good to have some choices. Gratitude to Bob Brines and MJK !
Good to hear the fuller bass worked out. What about the highs, balance ok?
Thanks for sharing "Experiment" , gives a nice perspective.
Don

texendo · « **Reply #853 on:** 14 Jul 2006, 06:33 am »

LarryC, or anyone else who's done this, how exactly do you go about cutting a circle out of plywood? I managed to cut out the six requisite boards with a "borrowed" circle saw by slipping the stoner at Home Depot a five spot. I found some cabinetmaker who had some fancy laser machine or something to cut "perfect circles," but he wanted about $250. No thanks. I'm not looking for Danish furniture grade here. I just wanna get the job done. Thanks in advance for any suggestions.

mcgsxr · « **Reply #854 on:** 14 Jul 2006, 09:49 am »

http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=3&filter=circle+cutting+jig&sm=1&so=1&raid=1&rak=circle_jig

If you have a router, this is the perfect way.

I have also simply used a jig saw, for the times that absolute accuracy was less important...

Wind Chaser · « **Reply #855 on:** 14 Jul 2006, 03:54 pm »

If you have a router, you can make your own circle jig... for next to nothing. I went to Home Depot and picked up a smooth diffused piece of plastic, the type used to cover fluorescent lights. Using an Exacto knife I cut it to fit the router, leaving enough length for the required radius which pivots at the opposite end one the router at the center of the hole you are about to cut. If you want to see a picture of mine send me a PM.

John

LarryC · « **Reply #856 on:** 15 Jul 2006, 04:41 am »

Quote from: nodiak on 14 Jul 2006, 05:24 am

That's great LarryC ! Another possibility, always good to have some choices. Gratitude to Bob Brines and MJK !
Good to hear the fuller bass worked out. What about the highs, balance ok?
Thanks for sharing "Experiment" , gives a nice perspective.
Don

Don,

The highs are still great. I have a lot more listening to do to determine if anything negative was introduced, but so far the sound balance is terrific. In my simple system the sound became much more weighted. Everything sounds better with the fuller bass. The mids and the highs are both enhanced in a positive way, warmer, smoother. With the BSC circuit/passive filter bringing the mids SPL down to the subdued level of the bass, when you bring up the volume, everything comes up together, more balanced.

LarryC

Dmason · « **Reply #857 on:** 15 Jul 2006, 04:49 am »

It will have done more than that; I am amazed at the difference in transparency when using AlO3 resistors. If you make the effort to use the good stuff, like Mills, Roderstein, etc., they will do the least damage, IMO. The precious signal must now travel through a "sand storm" but still, I like the approach. Tried it the other day, works a treat with good R's, and the Signature 30 just sails through the storm. The B200 is better balanced. Downside: SET need not apply. I prefer with 2.

Vinnie R. · « **Reply #858 on:** 18 Jul 2006, 02:40 am »

Hi Don,

Thanks for your suggestion.... I'm going to have to give it a try. Seems quick and easy (and inexpensive) enough to give it a shot. I'll let you guys know what happens...

Thanks again,

Nuuk · « **Reply #859 on:** 18 Jul 2006, 11:59 am »

Hi guys, some of you will know me, others won't so here is a brief introduction. In fact I am posting this here and in the thread at Decware as I will want to be involved in both threads.

I've been (seriously) into DIY hi-fi for about 11 years, I have a web site called Decibel Dungeon

http://myweb.tiscali.co.uk/nuukspot/decdun/index.html

and write for TNT Audio. I'm also found (as Nuuk) at diyAudio and one or two other forums.

I came to this thread a few days back due to what is a possible tragedy. I have some modified Goodmans 201's that I have used on OBs for a couple of years or so. Last week, I accidentally turned the volume up a bit too far and I think that I may have done for the 201's. They still play but I am detecting a bit of distortion. I could get them rebuilt but apart from the cost, there is a long waiting list so I have decided to move on and get them repaired when I am in a better financial position.

For a few moments I considered trying another type of speaker, then common sense took over and I couldn't see me using anything but OB's. A quick consideration of possible drivers led to the B200 and a Google search brought me to this thread. I have read all 93 pages of the Audiocircle thread and all 35 pages of the Decware thread so if you guys could tell me where to pick up my medal, I'll be much obliged.

OK, as I said, I have been using OBs for a few years now. I had the Goodmans 201s in a big box and one day wondered what they would be like on an OB. Well, rather than repeat the whole story, you can see words and pictures at

http://myweb.tiscali.co.uk/nuukspot/decdun/loudspeakers2.html#up1.

Right now, I have put my Ciare 250 baffles back in the system. The Ciares are good but no match for the 201s. My $64000 question now is are the B200's as good as the 201s? And yes, I know that there is only one way to find out!

Some have suggested going for the Ciares if you want to experiment with OBs. I would say not. Instead find some cheaper full-range drivers like the Cliffs that I used in my polystyrene baffle experiment. At £10 each it is a cheap way of trying OB and then you will have much more money left over to buy the B200s!

I have never had significant vibration from my baffles. When I built the oak-faced baffles for the 201s, there was a little bracing but I also clamped a large chunk of granite to the baffle just beneath the driver aperture. I removed this when I cut the aperture for the TL woofers to fire through.

The 'quietest' baffles that I have built were some experimental ones made out of polystyrene sheet. Again you can read the full story at

http://myweb.tiscali.co.uk/nuukspot/decdun/project.speakers2.html#top18

I may well build some more polystyrene baffles that will be curved with the driver mounted by its magnet to a separate chassis.

BTW John in CR, my TL subs came about because I was given the drivers and they were meant to be a toe-in-the-water job to get a bit more bottom end. Although I agree with you that using boxed woofers is a bit like cheating, I have to say that TL bass does go very well with the OB upper ranges. My woofers go up to about 70-80 hz.

The only real negative of the TL woofers is the large size. That, my desire to hear dipole bass, and a good offer on some 12 inch bass drivers, led me to build some new baffles and diople woofers.

I am still working on the amps and crossovers and of course now, will have to modify the front baffle to take a B200 instead of a 201! Here is a picture of the new baffles which were inspired by Bijorn's (Ludo) OB's.

I would also like to try the B200 on its own as I like the idea of a really simple system.

At present I am using a Behringer DEQ2496 with digital in and digital out to a NOS DAC. Used without any of the analogue sections, I find the DEQ is 99% transparent. I bought it originally to provide a bit of EQ on the dipole woofers when I get them up and running. But I find it very useful for a number of reasons. For instance with the Ciare 250s, a couple of dips placed at 2.5Khz and 5Khz make them much easier on the ear.

My digital souce is a much modified Philips CD723, I have Scott Nixon and DiyParadise Monica2 NOS DACs, a fair selection of DIY pre-amps, various Gainclones and class-T amps (yes, including Charlize). Again, you can read about nearly all my stuff on Decibel Dungeon and the pre-amp details are at

http://nickw.worldonline.co.uk/etc/preamp.html

I can't believe that I hadn't found these OB hotspots before but now I have, I will endeavour to hang around and contribute as and when I can.