[Rudolf]

I found a simulation with the Neo3 and some wide band driver on my HD. So it was easy to change for the B 200  .

The crossover is optimized for maximal flatness of the B200 in the first sim and with active filters. It would take much more time to do it with passive components and a good response at 4 kHz. I am working on that.

First sim is for the B200 and Neo3 in a shared baffle of 25 cm width. The Neo is placed just below the upper baffle edge:



On-axis response is fine, but off-axis-directivity becomes a mess above 1.5 kHz.

Second sim shows the Neo on top of the main baffle:



On-axis response would have to be adjusted, but the directivity is kept in good shape to much higher frequencies.

A simulation with the crossover at 4 kHz will be less precise, because the B200 is in break-up mode above 2 kHz and Boxsim can't account for that.
Since Boxsim can't simulate rectangular drivers, I have used a circular cone with the same area. So don't take this simulation as a construction blueprint - it is just for comparison.

Rudolf

[jonners]

Hey, that was fast. 
Many thanks Rudolf.
Edit:Btw, I have ordered the more sensitive Neo3W. I see that your sims are for the Neo3PDRW.

[Luigi]

Versys Rider

Did you see the recent review in Bike (UK) magazine of the latest Versys? They reckon it is about the most sane bike you can buy for any money! Currently Im riding the 2010 ZX-14. It is a rocket ship in a straight line; I've done 0-62mph in 3s flat on it, and it's meant to go into the 2s. It is still pulling at 260kph in fourth gear like there's no tomorrow.

My OB experiences are similar but different. Similar in that I just cannot stand box speakers any more. Went round to a friend's place the other day to hear his muy expensivo JBLs with a 10 inch woofer in a big vented box and horn loaded mids and tweets. The amps were even more megabucks, and I swear my OBs beat these hands down. The boxiness in the bass area was the first thing I noticed and couldn't get past that, but the imaging was just ordinary. He had a state of the art computer-based front end too. Just shows that if the transducers aren't great the rest of the system can be as expensive as all get out but still sound ordinary.
Regarding the crossover point, this is not my experience at all. The Alpha is rated at 46-3500Hz, so should be right in its zone around 300Hz. I've had them crossed as high as 2000 and they still sounded okay in my system. However, Im not using a digital crossover, just inductors I have lying around. At 300Hz crossover there is virtually no voice at all.

Rudolf
I have my B200s crossed at around 4000Hz and they sound vastly smoother than when they have no correction circuit in place. If what you say about break up modes above 2kHz is the case, should I be crossing these over lower down (currently at around 4kHz) and introducing the Neo3s earlier? The Neos are meant to go down only as low as 2000Hz.

[jonners]

Luigi -

Have you got the Neo3W or the Neo3PDRW?

[Luigi]

Jonners
I have the Neo3W, the higher sensitivity model.

[versus rider]

 Hi Luigi, my name on here is versus rider, that is the make of my downhill mountain bike, from USA from a boutique maker sadly no more. On the subject of motorbikes I have just sold my Hayabusa as I am unable to register it in France where I am going to live soon, as they have a 100hp limit and now have a Kawasaki Z750. Great fun it is to. I recently rode the Aprilia RSV4, that is some bike, totally inpractical for the road, foot pegs are too high, suspension too stiff and runs like a tractor in town, but wind that throttle open and hang on.

Versys Rider

Did you see the recent review in Bike (UK) magazine of the latest Versys? They reckon it is about the most sane bike you can buy for any money! Currently Im riding the 2010 ZX-14. It is a rocket ship in a straight line; I've done 0-62mph in 3s flat on it, and it's meant to go into the 2s. It is still pulling at 260kph in fourth gear like there's no tomorrow.

My OB experiences are similar but different. Similar in that I just cannot stand box speakers any more. Went round to a friend's place the other day to hear his muy expensivo JBLs with a 10 inch woofer in a big vented box and horn loaded mids and tweets. The amps were even more megabucks, and I swear my OBs beat these hands down. The boxiness in the bass area was the first thing I noticed and couldn't get past that, but the imaging was just ordinary. He had a state of the art computer-based front end too. Just shows that if the transducers aren't great the rest of the system can be as expensive as all get out but still sound ordinary.
Regarding the crossover point, this is not my experience at all. The Alpha is rated at 46-3500Hz, so should be right in its zone around 300Hz. I've had them crossed as high as 2000 and they still sounded okay in my system. However, Im not using a digital crossover, just inductors I have lying around. At 300Hz crossover there is virtually no voice at all.

Rudolf
I have my B200s crossed at around 4000Hz and they sound vastly smoother than when they have no correction circuit in place. If what you say about break up modes above 2kHz is the case, should I be crossing these over lower down (currently at around 4kHz) and introducing the Neo3s earlier? The Neos are meant to go down only as low as 2000Hz.

[Rudolf]

I have my B200s crossed at around 4000Hz ... If what you say about break up modes above 2kHz is the case, should I be crossing these over lower down (currently at around 4kHz) and introducing the Neo3s earlier? The Neos are meant to go down only as low as 2000Hz.

"Break up modes" was possibly not the best expression. If you compare some real world measurement* of the B200 (left) and my simulation (right), the radiation pattern really differs above 2 kHz: The simulated 30° response rapidly falls off above 3 kHz and the 60° response above 2 kHz. Neither does so in the real world, because the cone is not completely rigid at higher frequencies (as assumed by Boxsim), but radiates them mostly from its inner parts. This "break up" is intended, controlled and part of the driver design.



What I was trying to say in my previous post: Above 2-3 kHz my simulation is wrong (because of the rigid cone assumption) and can't predict anything about the interaction of the two drivers.

IMHO the real world measurement would suggest that you can/should keep your cross over as is.

Rudolf

* measurement courtesy of www.hifi-selbstbau.de

[Luigi]

Versus Rider
How about that, two Versus bikes, separated by one letter. Should have suspected it wasn't the other Versys. Still, guess you fully understand what I mean about the ZZR-14, given you've experienced the Busa, which is pretty much the same. I hear the new Z1000 naked bike is meant to be pretty special too.

Rudolf
Thanks for the advice on crossovers. Im so impressed with the Neo3 I feel like messing around with the Neo8 as well.

Anyone have much experience with the BG Neo8 units used OB?

[jonners]

My Neo3W's have arrived and I've installed them just above the B200's. They certainly give a clear and delicate sound but at the moment I feel that the HF is slightly too forward and a bit detached. I'm crossing over at around 2.5kHz at present but I have ordered some smaller inductors to try crossing at 4kHz. Meanwhile I may try adding a small resistor in series with the Neo's.

[richardcooper2k]

hi luigi/rudolf

can you tell me why you mount the widerange/midrange drivers at the top of their baffle ?
is it to reduce reflections of the top of the H frame baffle ?
are the dimensions of the H frame critical ?
would a U frame of the same dimensions give different results ?
i will be trying these things but would like to be well informed
any links to threads with more on this appreciated
thanks,
richard

[Rudolf]

can you tell me why you mount the widerange/midrange drivers at the top of their baffle ?
is it to reduce reflections of the top of the H frame baffle ?

Yes and more. We wanted to have the tweeter off the baffle. At the same time tweeter and midrange driver should be near together and somewhat at the height of the ears. This automatically led to the actual positions.

are the dimensions of the H frame critical?

A wider frame would have an advantage WRT efficiency, but most people would like to have the H frame as visually unobtrusive as possible.
Having the H frame as deep as it is wide is a good compromise. Less depth would reduce efficiency in the bass region, more depth could raise issues with the quarter wave resonance.

would a U frame of the same dimensions give different results ?

Yes. You may look into http://www.musicanddesign.com/u_frame.html and http://www.musicanddesign.com/Dipole-offset.html

Rudolf

[jonners]

I was beginning to question whether the Neo3's would tick the right boxes for me in combination with the B200, but now that I have crossed them over at 4kHz I'm very happy and I agree with Luigi's comments about the naturalness of the sound. Previously (crossing at 2.5kHz) I was going between different CDs trying to work out exactly what was making me uncomfortable. Now I'm enjoying the music again. 

[richardcooper2k]

that was really useful Rudolf

how do i work out the approx minimum baffle size for a given crossover frequency/driver ?

i'm thinking mids and above

thanks

[SAC]

Reading this thread feels like de-ja-vu for me having just discovered it.  I am not knowledgeable enough to remember all the theory/experiments I read on various forums way back but the consensus was that adding the Neo3PDRs to the B200s quite high (say 8khz) was the way to go.

You can read my experience of adding the Neo3 PDRs to my B200s (and dual alpha15s) in a relevant thread here;
http://www.audiocircle.com/index.php?topic=67341.msg711473#msg711473
"I finally got a chance to cross the b200 to the neo3pdr open baffled and crossing around 1khz.  I did bi-amp and do this by a PLLXO. 

Much better sounding!  I remember reading that any decent tweeter would "clobber" the B200 in the treble department and that has certainly been the case for me.  I had tried the BSc, the notch filter, rear firing tweeter at 2khz and then 10khz, but none to compare with this two-way arrangement. 

I was unsure of trying this due to the complications others suggested such as phase cancellations and the like, but the sound is incomparable now.  I doubt I will go back again  in this set-up.

P.S. tri-amping dual alpha 15s+B200+neo3 pdr was amazing!  Even my wife from the other room noticed a huge change had taken place, it now sounding "like a movie theatre"."


In the end, a first order crossover much higher at 8khz was superior sounding (I forget the reasoning right now) with the set-up as follows;
3-way active, all open baffle, for movies and music, at low to moderate SPL's.
4x alpha 15a - paralleled to give 2x4ohm, 6dbLP@67Hz
2x Visaton B200 - 2x6ohm, 6db@300&600HZ (plus unusual magnet mount)
2x Neo3 PDR, open backed, 2x4ohm, 6db@8000Hz

The passive line level crossover (PLLXO) is awaiting a box. It is connected to three stereo power amps which will be replaced by one amp9b per speaker.

[canzld]

I'm sure its been done before, but everyone who has the B200/ alpha combo owes it to themselves to at least try this once (IMO)- many thanks to StigErik for his thread/explorations of baffleless drivers on diyaudio which showed me the direction.
I thought i had a big open soundstage before, with excellent clarity and good imaging using a relatively small baffle for the B200 - well - I'm not sure I'll be going back to a baffle anytime soon 
Frames took 30 minute to put together with scraps of wood i had lying around. Tying the drivers up took another 30 as i figured how to get them to hang straight. Only adjustment required - maybe upping the crossover slightly if you are down near 100 (currently about 180, 1st order)
they probably measure like c...p (no gear, so I can't tell you), but to my ears, and in my room, they sound rather good 

[SAC]

Canzld

Is that B200 equalised somehow?  Surely it will not sound good without eq in that set-up!?

[canzld]

No - no capability at hand. I don't equalize when I have the baffled speaker either. The B200s are phase plugged and I've never had quite the issue that some do with the B200 rising response on wide or narrower baffle, provided the speakers were kept well,well off the wall.  This was a quick experiment so see how suspending the drivers would sound - after having followed StigEriks explorations -and without great expectation. I was very surprised how good they seem, the early bass rolloff is clearly evident compared to the baffled speaker, but adjusted for by raising the crossover. I can hear a slight peak, probably around 1.5-2K if i had to guess, but not bothersome to my cloth ears. I have no pretentions to speaker design - just to a bit of empirical learning and playing around a bit. I also like the B200s very much just by themselves and always tried to use the alpha as minimal  bottom end support.
As to the sound - well I've been to a lot of acoustic (classical) concerts in my time and to my ears - removing the baffle or suspending the driver, whichever it is, made the presentation of the sound significantly more live -of course as always, YMMV

[SAC]

I have no active eq capabilities either.

I'm looking for an excuse to take my B200s out of my active three way detailed earlier (now 4 way with a 4inch mid thrown in) and substitute them with a 91db 8inch woofer, the Monacor SP-8/150PRO, at 91db.  With a low qts of 0.32 it may not work out but I'm hoping the increased power handling and 7db's extra sensitivity may make the difference.

I'll then have my phase plugged B200s and spare pair of alpha15s to try your set-up. 

[-Richard-]

Very interesting Canzid. Thanks for posting your photos and for sharing your insights with us.

I am still exploring ribbon tweeters... between the cracks and folds of my life. Your experience suggests that the speakers of the future can be designed so that they are entirely free of any enclosure or baffle... in that sense the driver manufacturer becomes the speaker designer at the same time (and would require the neccessary talents of both). A pardigm shift of thinking is all that is required.

I have come to realize... through the haze of my so-called conscious perceptual life... that the sound I have settled on in Open Baffle speakers is entirely "made up"... it is a completely subjective sound that emphasizes the mid-range and upper bass... and that that sound seems to supply Deborah and I with the sound quality that brings our particular musical choices to life (in my room with my equipment and so on). And what is more... I cannot seem to bring myself to think that there is anything wrong with that.

Only when we take it upon ourselves to put together our own Open Baffle speakers do we begin to realize that we can shape the sound anyway we like (within the synergy of the rest of our system). Somehow today, this seems like a form of freedom that I had not before fully realized. In my world, the ears and the music reign.

Warmest Regards ~ Richard

[canzld]

Very interesting Canzid.

canzld   canada-new zealand

Your experience suggests that the speakers of the future can be designed so that they are entirely free of any enclosure or baffle..

All credit to StigErik, definitely not me. I just stuck my finger in the water to see how warm it was 

I have come to realize...  that the sound I have settled on in Open Baffle speakers is entirely "made up"... it is a completely subjective sound that emphasizes the mid-range and upper bass...

I had rather  inferred your sonic preferences from copying your crossover settings for a while…nothing wrong with a rich mid range – that’s where the music is (to use an old cliché)

And what is more... I cannot seem to bring myself to think that there is anything wrong with that.

I shouldn’t worry Richard, that’s all I do. Let’s face it – that’s what everyone does when they buy loudspeakers. They pick the ones that, along with all their manufacturing, budget, driver and cabinet compromises, sound the best to them, their ideal of how reproduced sound should sound. A little DIY has just let us see into the process a little more clearly. Of course, some are far more serious and are trying to produce speakers that very accurately reproduce their source material and kudos to them. But in the end the aim of the speakers is to fool us into believing a live musical event is occurring in front of us, by whatever means, and speaker designs that don’t convey music with expression will quickly be discarded. Whether it will be the ones that most accurately portray the source recording or ones that pander to our perceptional abilities that will ultimately be the best I'm not sure, some of both undoubtedly. So enjoy your musical event - seems to me you've found exactly what you were looking for, most aren't so lucky. My own tonal preference is set by sitting very close to my local symphony orchestra. So until I manage to stuff the orchestra into a little box, I'll probably always be a little disappointed  (whoops - no boxes allowed - (no)OB only  ). In the meantime I'll create my own musical event at home with my highly flawed, but highly enjoyable (well...at least to me) DIY speakers.
all the best