[mcgsxr]

A series of Xovers, actually...

The JVC EX A1 has a built in Xover, of unknown (yes, EVEN TO JVC...) design, that cuts bass from the mains, and out the coax.  From the coax, to my old analog Teac EQ.  From the EQ to the 300w BASH sub amp, which has its own Xover.

I am tuning by ear, as that is all I have...

Once my new little tube amp arrives, I will explore running high and low level feeds to the sub, and play around with that.

Good Q, likely a protracted, hard to comprehend answer!

[Vinnie R.]

MarkC,

I am now playing with a carefully calculated BSC-circuit consisting of 8 ohm MOX in parallell with a 1 mH inductor in the signal lead.
So far absolutly the best. Very good in fact !

/Erling

Hi Erling,

You sir are ONTO something here!  Very good in fact, INDEED! 

More to follow...

Vinnie

[Wind Chaser]

I am now playing with a carefully calculated BSC-circuit consisting of 8 ohm MOX in parallell with a 1 mH inductor in the signal lead.
So far absolutly the best. Very good in fact !

Is this the idea...

                                                                                  8 Ohm MOX
+ + + + + + + + + + + + + + + + + + + + + +                      + B200  Positive Terminal
                                                                                        1 mH   



- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - B200  Negative Terminal


John

[scorpion]

John,

That's right !  And thanks, Vinnie !

/Erling

[Wind Chaser]

Thanks Scorpion, I'll give it a try and see what happens, but first I have a little issue with my source I need to work out.


John

[Vinnie R.]

John,

That's right !  And thanks, Vinnie !

/Erling

Scorpion,

What software did you use to calculate the BSC circuit values?  What frequency does the BSC circuit start coming into play?

I hear a BIG change in the presentation of female vocals. 

Hopefully I'll have some more time tonight to listen...

Thanks,

Vinnie
 

[scorpion]

Vinnie,

First, ladies voices ! Yes, it is strange that once you come into play with this loudspeaker's balance, the first thing you notice is how well recorded woman voices come over physically. They are not only good, they are there/here ! Male voices are bettered too and I am now playing my whole Ben Webster collection over again and enjoying. But I think that the overall clarity and definition of the speaker is a bit bettered too. How that can be ?

I have given the link to the software earlier and repeat it now: http://www.tolvan.com/edge/ . It is presumably the best software for
flat baffle OB calculation and baffle step correction there is (beside Svante's other software), and it is freeware ! The good point is that you can also see in graphs the effects. My calculation aimed to take down the steep frequency rise between 800 Hz and 2 Khz. With this aim you suddenly realize that your step down alignment has to start earlier to come into play. So with this simulation I have used 550 and 1300 Hz as  values for f1 and f2. Now these frequencies also interact with bafflesize and impedance so it is not so a clearcut question to answer. I do think that
1 mH and 8 Ohm is a very good starting point for experimentation for any baffle size.

At this moment I have added a Zobel-filter 5.6 ohm and 9 microFarads. With my parts at home I now play with 1.68 mH and 11.3 ohms, just depending of what I had at hand. Now I think I miss something above 10000 Hz but the overall impression stands as before. I am still playing with the test baffles 100 x 70 cm flat wiht the middle of the speakers 16 inches above floor level. But as you all know listening impressions are so easy to get accustomed to. This shows that there is an area open for your own optimization. These speakers are truely capable of a very remarkable performance. 

/Erling

[Vinnie R.]

Scorpion,

Thanks for sharing this info!

Best regards,

Vinnie

[scorpion]

Perhaps I should have given som more info about the correction. 550 Hz is supposed to be the start frequency and 1300 Hz is where the response is down 6 db. This is however dependent upon bafflesize and impedance. In the actual simulation with 45 cm width and 110 cm height baffle and 6 ohm impedance the actual response (simulated) is down 2.5 db at 550 hz and 5 db down at 1300. 6db is reached at 2000 Hz and the full effect of 7.2 db down you have a little bit over 3000 Hz. In reality a bafflesize of 45 cm width actually boosts frequency response between 300 and 800 Hz so even if you in some way try to calculate the response, it is not until you hear it that you can be sure of your success. But as I said before 8 ohms and 1 mH is a good starting point for experiment.

/Erling

[ChuckT]

Hi all, new here.

Just got a B200 and putting into a 35"x14" baffle with small wings, no bass at all and roll off fast at 200hz, worse than Visaton curve.
And the tile up responds does stands out. 
So I think a R-L circuit is really necessary. Still experimenting with the few parts I have. I'll probably need to add a tweeter crossing at 8~10K later.

Check out the spreadsheet here, goto the R-L sheet, input your B200 responds and input various L-R values to see how the responds change.

http://www.pvconsultants.com/audio/targetgen/pcdc.htm


...Chuck T

[ChuckT]

Oh, a zobel is absolutely necessary if using a R-L circuit, otherwise, the inductor won't be as effective due to rising impedance of B200.

[mcgsxr]

ChuckT, could you share what amp you are using?  I might be a voice in the wilderness... but I have found that amp synergy does AMAZING things to how the driver responds.

I would also add that I have not heard one of these on anything less than a 36 inch wide baffle, that I have arranged to have folded, to assist with the visuals...

Just my thoughts.

[ChuckT]

Hi mcgsxr,

Doesn't everybody here uses some form of class-T amp Kidding.
I am using the 41hz amp6 with 14V, had enough bass when driving my 85db 2-way diy Revalator.
But yes, the baffles is a bit small to expect much bass but I was expect a bit more than that. I got over 20dB difference between 100hz and 5khz with my meter. Maybe it needs more burn in.

[Rocket_Ronny]

Scorpion:

Wind Chaser wanted me to pose a queston for him as he is away from his machine for a few days.

Regarding the 1 mH inductor, what is recommended?  Air core or copper foil?  Any advantage to the perfect layer?  14. 15, 18, 20 AWG?

Rocket_proxy_Ronny

[mcgsxr]

ChuckT, sure everyone around here HAS played with a T amp, but not all adhere to them.  I understand that there are several very happy Charlize users here on this thread, but for me, the cheapest, best sound comes from an old 50's Magnavox single ended EL84 Class A amp... $125 off eBay.  Good bass, wonderful mids, good highs.

I would break out the duct tape, and some cardboard, and see if "growing" those wings another 10 inches helps or does not, when running full range.

It may not, the T amps, for me, in my room, NEVER had presence below 150Hz, but it is a big room - 25x35x7.5 unfinished basement, so I ended up with subs anyway. 

Still deciding if I need them for music, with this little Maggie amp though, it is a real treat.

[ChuckT]

Hi mcgsxr,

Yeah, I know, but it is very amp. I had also try the gainclone, but the T-amp is a quite a bit better, esp in the bass control.
Still, it might be possible that the tiny t-amp may not be compatible with OB that might need a lot of juice to produce good bottom.

btw, I already had 7.5" wings on both side and 19" off the floor.

[hurdy_gurdyman]

the cheapest, best sound comes from an old 50's Magnavox single ended EL84 Class A amp... $125 off eBay.  Good bass, wonderful mids, good highs.

This isn't surprising. The old Magnavox was an under-damped amp that had a typically under-damped bass that would get "fuller" under around 100 Hz or so. This was common with many vintage 60's amps. The old Scott I had also had a bass rise/bloom. This should be a perfect compliment to the B200's lean bass. A case of good system synergy. Most decent EL-84 tube amps have a great midrange and at least good highs. It's the nature of this very special tube.

Dave

[scorpion]

Rocket_Ronny

Fact is I do not know. My own 1 mh were air wounds 1.4 mms and the 0.68 mHs were foils type. But I think that ferrit core wouldnot
be that detrimental because you are not in the frequency range where it matters. 

/Erling

[corloc]

Hi all, new here.

Just got a B200 and putting into a 35"x14" baffle with small wings, no bass at all and roll off fast at 200hz, worse than Visaton curve.
And the tile up responds does stands out. 
So I think a R-L circuit is really necessary. Still experimenting with the few parts I have. I'll probably need to add a tweeter crossing at 8~10K later.

Check out the spreadsheet here, goto the R-L sheet, input your B200 responds and input various L-R values to see how the responds change.

http://www.pvconsultants.com/audio/targetgen/pcdc.htm




...Chuck T

Hi Chuck, 

I use a el84 PP Amp,  I'm curious how many hours you have on the B200's?  Mine sounded like utter Cr** for the first 10hrs.  The Biggest changes were at 60 and 100 hrs.  The rest of the changes sence then are more subjective.  The reasone I say this is I wouln't screw around with filters and baffles too much untill you have 100 hours on them.  Otherwise your trying to hit a moving target.

Chris

[ChuckT]

Hi, I have used for around 30hrs, so yes, more break in is need.
I don't mean the b200 doesn't sound good, but I believe that is room for improvement.
I see that there is a relevant thread in the OB circle, so I am going to move over there.