MOX in parallell with a 1 mH inductor for the B200

scorpion · « **Reply #140 on:** 19 Jan 2007, 08:51 pm »

If more people can measure the B200, it would be interesting also to have your data !

PS. I found an informative page on LS data on the Eminence Web: http://www.eminence.com/resources_data.asp .
I also had the impression that voice coil inductance usually is measured at 1 kHz. For tweeters often 20 kHz is quoted.

/Erling

Rafal · « **Reply #141 on:** 23 Jan 2007, 01:46 am »

I really hope you guys can help me. I'm going crazy here.

I am trying to determine if I should keep the 6.8ohm, .68mH network (premium parts from partsconnexion, set me back $100CAD). I keep swapping it back and forth. Without it, I cross my MJ Accoustic Reference 150 sub at 70Hz and with the network, at 57Hz. Here are my impressions:
With the network, the treble is shightly less pronaunced, allmost sounds compressed.
The bass is defiantely deeper which would have been nice If I didn't have the sub. The detail is about the same.
Without the network, the treble is slightly more pronounced (almost not noticable and the bass is leaner (without the sub). I do however preffer the integration with the sub and no network. Overall, it sounds cleaner and more spacious. Definately more exciting.

I struggle because I've read that for a lot of you the treble (without the filter) is a real problem but I kind of like the sound. It may however end up being fatiguing which I don't want. I wish there was a different / simple way to even out the trebble response without having to resort to the filter.
I hate flip flopping back and forth. I just want to set thing up for good and start enjoying music.

What do you think I should do?

opnly bafld · « **Reply #142 on:** 23 Jan 2007, 02:12 am »

I know of quite a few, myself included, that have tweaked it without a filter and with bass augmentation and are happy/satisfied with it.
Have you tried dampening the back of the driver?

Lin

markC · « **Reply #143 on:** 23 Jan 2007, 02:45 am »

Rafal;
If only it were that easy...
I've been playing with the B200 in open baffle for 8 months now. I was amazed by the brilliance of the upper mids compared to my previous commercial speaks, but after some time I felt that they were drilling a hole in my head.
In comes the kick ass sub woofer and things were very alive and rounded out -but after a while only at higher volumes which became fatiguing.
Next up a bsc filter. then a notch filter, then a zobel, then a tweeter...

I believe that no loudspeaker can be perfect. But as I expand on the possiblities, I find that I am getting closer to what I like. Some changes are better, some not. My other speaks have been stored away for the forseeable future.

If you prefer the output with sub and no filter, listen to it. Check what you like and dislike about what your hearing. Your not going to get this set-up exactly where you want it in a week.

Your room, your gear and your ears are different from mine and only you'll know what you like best. And the only way to achieve it is to follow other's experiences as guidelines and experiment for yourself.
There are many variables, such as baffle size and driver location within the baffle and filter circiuts.
This, of course, is my experience and opinion.

I have't quite got it right yet, but it's getting close. If only I could find some .035 mH inductors...guess I'm going to have to roll my own.

MJK · « **Reply #144 on:** 23 Jan 2007, 03:08 am »

Quote

What do you think I should do?

Pick the configuration you like better. It does not matter what anybody else thinks, writes, has used in their system ....... Live with it for a while. Change the set-up if it becomes less than what you ultimately want from the speakers. Stop considering what others say or think. Be open to changes that you might like better, it is a great adventure. Enjoy and have fun.

corloc · « **Reply #145 on:** 23 Jan 2007, 03:27 am »

I have to agree with MJK, I used to think the B200 didn't need a filter at all. I tried one and found it evened thing out, but at a price of sensitivity. So the driver sounded kind of closed, but this weekend I got off the DIY amp thing and bought a Marantz PM7001. Having 70w compared to 10w make a big difference in my setup. The drivers don't sound as open, as without the filter, but the filter is much more livable and enjoyable.

Only thing to do is experiment.

Rafal · « **Reply #146 on:** 23 Jan 2007, 04:23 am »

I know that I should do what I like most, and that's what I try to do. I put the filter back in and I tweaked the sub phase adjustment. It made a big difference and now the opennes without filter is back. I'll try it to see if I'll be happy with it.

Quote from: corloc on 23 Jan 2007, 03:27 am

I have to agree with MJK, I used to think the B200 didn't need a filter at all. I tried one and found it evened thing out, but at a price of sensitivity. So the driver sounded kind of closed, but this weekend I got off the DIY amp thing and bought a Marantz PM7001. Having 70w compared to 10w make a big difference in my setup. The drivers don't sound as open, as without the filter, but the filter is much more livable and enjoyable.

Only thing to do is experiment.

That Marantz looks like a really nice amp (+ tone controls)

What does it sound like? Myself, I was using Charlize and just recently built an LM3875 gainclone based on Peter Daniel's premium kit (50w/ch). They both sound nice and are very close but the jury is still out on which one I preffer. Ultimately I'd like a 40w/ch tube amp and if I sell my Tannoy System 800 A, then maybe I'll enter the world of the glow.

Quote from: opnly bafld on 23 Jan 2007, 02:12 am

I know of quite a few, myself included, that have tweaked it without a filter and with bass augmentation and are happy/satisfied with it.
Have you tried dampening the back of the driver?

Lin

Lin, this weekend I covered the back of the panels with black felt but I didn't do anything to the drivers.

Quote from: MJK on 23 Jan 2007, 03:08 am

Quote
What do you think I should do?

Pick the configuration you like better. It does not matter what anybody else thinks, writes, has used in their system ....... Live with it for a while. Change the set-up if it becomes less than what you ultimately want from the speakers. Stop considering what others say or think. Be open to changes that you might like better, it is a great adventure. Enjoy and have fun.

MJK,

This is fun when things work out. I do it not for the sake of doing it, but to get a great sounding system for relatively little money and to enjoy my music more. If I had the money, I'd just go and buy large Tannoys and some nice tube amp and be done with it. I'd spend my free time on my real passion which is sculpture. This is a great hobby but it can sometimes be frustrating.

Anyway, one lives with the choices one makes.

Thank you all for your comments. Keep them comming.

scorpion · « **Reply #147 on:** 23 Jan 2007, 12:11 pm »

I'll report on some of my doings lately. I was not very original when proposing the BSC-circuit. Visaton have them in all their publish designs for the B200 but with very varying values. What I did was to seek the best compromise and I think that was done successfully.

I have gone 'digital' as far is possible. I finally went away and bought the Behringer DCX 2496 (you can have them in Europe, I think they have improved the power supply and there is a new software allowing more filters) and I am very satisfied with what this unit produces. So now I take the digital signal out of my Sony XDP-930 (very good transport I think) to the Behringer unit. Amplification for the B200 is a Trends TA-10 swithching amp. I am very pleased with its sound with B200 fullrange. I find that I am balancing at the edge of distortion most of the time. You won't get many watts out of this amp but the sound is extremly good.

The Behringer surprised me, it is running circles around the 8 unit 1543 NOS DAC I used previously, producing a very natural sound. And I can also optimize bass lift with this unit. For the B200 I use 1 mH + 6.8 mikroF for the LR-circuit, no Zobel. I have put some felt over the back of the B200s to damp backwave treble. To me this gives a bit better balance in my room, but we are talking about nuances.

Some speaker reviewers make a point of speakers sounding very good in another room (indirect listening) in their reviews. These are about the silliest remarks ever done. You can all very easy prove that case by listening to any simple Transistor Radio from a distance and it will sound better than when you are directly in front of it. Well, my B200 sound very good both up front and from a distance.

I will give some links connected to my next project: http://www.kensonpro.com/matro/index.htm (in Swedish but a lot of pictures will give you the setup) and http://www.fesb.hr/~mateljan/arta/news.htm .

/Erling

Rudolf · « **Reply #148 on:** 23 Jan 2007, 12:46 pm »

Hi Erling,
I could not find anything about your Sony XDP-930. So how do you solve the multichannel volume control problem with the DCX 2496? I don´t see you controlling the volume at every single TA-10 in the line.

Rudolf

scorpion · « **Reply #149 on:** 23 Jan 2007, 01:32 pm »

Rudolf,

Only two channel at the moment. I'll stick to my old NAD Combo for bass. I have made two bass-solutions, one sort of U-frame with 8 of those cheap Westra 8" units and another one consisting of 4 12" units cheap Chinese and P-Audio OEMs in guite a different setup, two of these for stereo. I am not ready to say something definitive about these yet. That's were the measurement project comes in. But you are of course right I have to invent the 'Universal Automatic Feedback Volume Leveller' , the 'UAFVL' there is no Blueprint yet, it may of course exsist already. By the way I discovered that South Africans are the most acronym proned people in the world. I think I am right on this.

/Erling

Polarbear · « **Reply #150 on:** 24 Jan 2007, 12:08 pm »

Quote from: scorpion on 23 Jan 2007, 12:11 pm

The Behringer surprised me, it is running circles around the 8 unit 1543 NOS DAC I used previously, producing a very natural sound.
/Erling

Hi Erling.

I agree on the nice sound from the Behringer. It smoked my ScottNixon NosDac.
Have you done the output mod? Takes the unit to the next level. I'm also planning a clock and PSU upgrade from Selectonic.fr

Can you make the same filterfunction on the behringer, as you do with the resistors and inductors on the B200 (to avoid the passive components on speakerlevel)?

Cheers
Bjørn

scorpion · « **Reply #151 on:** 24 Jan 2007, 01:04 pm »

Björn,

It is only a couple of days old. Still learning about the setup. I think I would be able to optimize a bit on the B200 with the filterfunction.
I found the measurement link on 'Hifisentralen'-thread and this I think will be of great help to get the filters right. But I am still amazed because every CD I put in seem to gain especially in definition and overall sound.

I'll send you a mail. I have to be assisted regarding upgrades for the Behringer. I finally found a local supplier for 'tovet ull' for my speaker
experiment. I had mail contact with the Norweigan guy who implemented it and had some further advice. Thanks !

JohninCR obviously thinks in the same direction as I do regarding speaker mounting. I liked Nick Whetstone's work with his Hawthorne Test Baffles. I am thinking of something similar but simpler. Just some small MDF-rib in the back of the speaker with hooks attaching the element. The MDF-rib and the speaker front would then be isolated from the baffle with the wool felt. Simple and may be effective. The wool should transform friction into heat, good in the Winter !

Cheers !

/Erling

JohninCR · « **Reply #152 on:** 25 Jan 2007, 04:50 am »

The thing I like about the single central support piece for a magnet mount is that as long as you don't make it very thick you don't really affect the radiation pattern. You don't get much off axis strength and rigidity, but the mechanical forces are directly on axis anyway.

Russell Dawkins · « **Reply #153 on:** 25 Jan 2007, 05:57 am »

Quote from: scorpion on 23 Jan 2007, 12:11 pm

Some speaker reviewers make a point of speakers sounding very good in another room (indirect listening) in their reviews. These are about the silliest remarks ever done. You can all very easy prove that case by listening to any simple Transistor Radio from a distance and it will sound better than when you are directly in front of it. Well, my B200 sound very good both up front and from a distance.

/Erling

I don't think this is so silly, and I don't think the transistor radio example is particularly germane.

Most speaker listening tests and measurements are done on, or nearly on the speaker's axis.
Generally, only by leaving the room can you get any idea of the tonality of the total energy being introduced to the room by the speaker.

I think that this (flatness of room response) is an important and often overlooked factor contributing to the sense of realism and the possibility of forgetting the technical side of the experience and enjoying the music.

I also think there may be merit in the notion that dipolar radiation may be most important in the bass end of things, as it is the only avenue open to us to gain any directivity in that region to match the directivity that is almost unavoidable at all other frequencies, and thus avoid the otherwise inevitable situation of having too much bass energy being radiated into the room as an unavoidable consequence of getting the on-axis response through the bass region right.

JohninCR · « **Reply #154 on:** 25 Jan 2007, 06:23 am »

Russell,

Makes a couple of very good points. If it sounds like a transitor radio from outside the room, then it's far less likely to sound truly real inside the room. His point about dipole bass is my biggest sticking point with every OB solution that takes the easy way out and boxes up the bass. We fall in love right off the bat with the open an natural mids of OB speakers, however, it's the bass region where the real gains are for OB and unfortunately a single small driver isn't going to do it. I can't wait for Scorpion's report once he dials in his multi small driver projects, since these 15's can get unruly large once they multiply.

Rafal · « **Reply #155 on:** 25 Jan 2007, 01:59 pm »

Speaking of bass solution, I have been playing around with the filter and integration of my sub. I gotta say that with the filter the bass extension of my fairly modest baffles is dramatically deeper. I am getting some nice extension in 50hz region and this makes the sub no longer neccesary. I do however miss important lowest octaves without the sub so things still sound fuller with it. I have the sub crossed at 45 Hz now and most of the bass above that is still handled by the OB B200 drivers which gives it the nice dipole effect. I was listening to Gnarles Barkley's "Crazy" on my HT set up (Tannoy Mercury 3's) and then compared it to my OB setup. The OB is so much more lush and organic that there is really no comparison. It is also easy to listen to loudly. I am pretty happy with my integration right now and the next 2 steps will be:
1. Optimizing the baffle and avoiding the resonance by using some serious dampening on the back side (maybe acoustic tiles) . Right now there is a bit of coloration sometimes with the male voices.
2. Trying different, maybe tube, amps. i am using the LM3875 Gainclone and it's pretty nice, but I want to compare it to some other designs.

MJK · « **Reply #156 on:** 25 Jan 2007, 03:47 pm »

Quote

The OB is so much more lush and organic ....

Sorry for the OT post. I keep seeing the descriptive word "organic" applied to the sound of equipment. What does "organic" mean in terms of audio equipment performance or sound?

Rafal · « **Reply #157 on:** 25 Jan 2007, 04:12 pm »

Quote from: MJK on 25 Jan 2007, 03:47 pm

Quote
The OB is so much more lush and organic ....

Sorry for the OT post. I keep seeing the descriptive word "organic" applied to the sound of equipment. What does "organic" mean in terms of audio equipment performance or sound?

To me, it means the opposite to "synthetic" and "artificial". In other words, more "real" I hope this helps.

ChuckT · « **Reply #158 on:** 26 Jan 2007, 12:05 pm »

Hi all, just want to share some recent discovery.

I have just switch from a T-amp to a TI purepath amp and the bass is much better now, it doesn't go lower but there is more bass.
In combination with the RC filter the sound is much more balanced.

Now this change may also be due the dac (Non-OS TDA1541) T-amp (TA2020, similiar to Trend TA-10) combination rather than just the amp itshelf.
The TI purepath is direct digital in (no need for dac).

Base on this, I am guessing that the B200 in OB is quite demanding on amp in the bass region. If there is not enough juice, no bass.

BTW, from my diy experience. I would rate my diy amps TI purepath (TAS5110) > T-amp (TA2020) > chip amp LM3875

PS.
I had a deq2496 but I have tweaked it to death (literally)

But if you do the output mod (direct out from dac ak4393), the sound jumps to another level in terms of purity, openness and detail.

corloc · « **Reply #159 on:** 26 Jan 2007, 07:50 pm »

ChuckT,

I think I'm going to agree with you on the B200's need more power in the bass region.
I've used a el84 PP 10w (diy),
a chip amp (kit) 10w clean (up to 25w),
Sherwood S-5000 20w (tube 7189)
Marantz PM7001 70w (currently used)

The B200's respond well to all of the well, but the Marantz has the best bass. I bought the PM7001 for the tone controls. I find that I don't really need them. I am still using useing a 1.5mH and 5 ohm filter.

Chris