My Open Baffle-Less Speaker Journey

[TransFi]

Maybe it should be the ultimate HiFi test...”do you hear imaginary front door knocking” 

I’ve experienced it a few times with my system I thought it was annoying but now I know it’s a sign of quality.

Keep the stories coming Vic loving all of your experiments

 

[Johnjc]

I have heard Vic new speakers once. They do scale like nothing else I heard. I have a similar setup but use the Selenium Neo's for bass drivers. Whilst I get good bass they are no way near what the Dayton UM18 produce. What is surprising is the level of clarity throughout the mids and treble. The bass does not get in the way.
The system is the closest I been to that live experience of music It takes no prisoners and if you like a seductive audiophile sound this is not for you.
John

[ian]

Maybe it should be the ultimate HiFi test...”do you hear imaginary front door knocking”

Interesting, I sometimes experience the audio opposite in that noises off seem to be part of the music 

[ZM1080]

Transfi,

have you thought about what (negative) contributions your pipes may be adding?

I am building a loudspeaker from commercial boxed units, but tied together with aluminium tubes. These tubes will be partially filled with particles (exact materials, sizes and fill percentage to be assessed) to keep down pipe resonances. Particle damping is well known, but the nitty gritty** has to be well researched.
My ideas are here:



I call it an mdr, which stands for 'modular direct radiator', but it is really just JPW upside down!

** my attempt at humour.  

[TransFi]

The pipes are not contributing anything. They are not in direct contact with the drivers which are totally isolated. That was one of the reasons for using such a system, to prevent vibrations from reaching the floor.

[0TT0]

On your you tube film:

The cones move for and back wards, but the driver it self do that too.

And for the 2 drivers at the upright bar I suspect they will do that also.

[JohnG]

I've visited this thread a few times now.
It has got my Attention ! OB's always do.
I am on the verge of coming away from the idea of Stacked 57's, I am nearly giving up on the search for a set of OTA Quads, that are a match to my own.
For too many years now, I have been wanting a set of Passive OB's.
The design is a magnet to me, and through another forums annual meet up, I have heard a few impressive models, one of the designs is very special, I would really like to mimic it.
The design in question looks very nice to me, and has got me thinking as I have lots of galv tube in 33mm OD.
Any suggestions on a Passive version ?
If a new thread is required to discuss let me know.   
 

[TransFi]

On your you tube film:

The cones move for and back wards, but the driver it self do that too.

And for the 2 drivers at the upright bar I suspect they will do that also.

Yes. they move at 5hz, but above that they are stationary. The PRV's operate at a much higher frequency so dont move at all....

[TransFi]

I've visited this thread a few times now.
It has got my Attention ! OB's always do.
I am on the verge of coming away from the idea of Stacked 57's, I am nearly giving up on the search for a set of OTA Quads, that are a match to my own.
For too many years now, I have been wanting a set of Passive OB's.
The design is a magnet to me, and through another forums annual meet up, I have heard a few impressive models, one of the designs is very special, I would really like to mimic it.
The design in question looks very nice to me, and has got me thinking as I have lots of galv tube in 33mm OD.
Any suggestions on a Passive version ?
If a new thread is required to discuss let me know.  

Passives might work well with efficient woofers. With these beasts you would need one hell of an amp and crossover to get any sense out of them....I wouldn't know where to start with a crossover.
 

People that make passive OB's usually choose a very efficient woofer with high QTS to compensate for roll-off. This design is just the opposite!

[Colin_EJJ]

A fascinating project, thanks for sharing it.

One of the best bass systems I've heard came from a 18" bass driver run OB. I thought at first it was in a closed box so was surprised when I realised it was run open. It ran at low frequencies, coming in below a pair of our Eikona drivers in reflex cabinets. The way it opened up the acoustic of the recording venue was astonishing and very addictive.

Do you find the orientation of the speakers has any impact on room modes, ie if the bass units are rotated 90º?

[TransFi]

Hi Colin

You hit the nail on the head with OB bass....there is nothing like it. Once you hear it, you can't go back to a box. I have had bass players in my house that are stunned by the fidelity OB bass can give.

With my 'boxer' woofer configuration, there is absolutely NO BASS coming from the gap between the woofers. Everything radiates from the front and back, so its quite directional. I have tried sideways orientation, as well as floor/ceiling orientation but the bass seems to cancel out.

Cheers

Vic

[ian]

Hi Vic,
Just been reading about your complete system and how you power these speakers.  Good read for anyone else fascinated by these speakers.

https://www.trans-fi.com/my-system

[itskeith]

Well written Vic and thanks for linking Ian 

[lapierrerider]

Hi Colin

You hit the nail on the head with OB bass....there is nothing like it. Once you hear it, you can't go back to a box. I have had bass players in my house that are stunned by the fidelity OB bass can give.

With my 'boxer' woofer configuration, there is absolutely NO BASS coming from the gap between the woofers. Everything radiates from the front and back, so its quite directional. I have tried sideways orientation, as well as floor/ceiling orientation but the bass seems to cancel out.

Cheers

Vic

totally agree about the quality of OB bass, I don't have room now so have to live with boxes.

[Paul]

With my 'boxer' woofer configuration, there is absolutely NO BASS coming from the gap between the woofers. Everything radiates from the front and back, so its quite directional. I have tried sideways orientation, as well as floor/ceiling orientation but the bass seems to cancel out.

I've found myself coming back to this thread again and again and was particularly interested by two comments you made, one being that the experts will say that this set-up cannot work and the other comment above that the speakers are quite directional and that there is no bass coming from between the speakers. I've been trying to figure out why this set-up does work (and was also wondering why you have a gap between the bass drivers when you could probably have just bolted them together face-to-face) and have a strange thought that maybe the way you have joined your bass drivers has created a 'phantom baffle'.

This is all just supposition but if you regard the space between the drivers as an actively induced acoustic dead zone maybe that dead zone extends out far enough from the drivers to keep the back wave and the front wave separated for long enough that they don't cancel each other out. If that was the case then the 'phantom baffle' would have a soft boundary and a soft ending which may also explain the lack of detrimental baffle effects that you mentioned in regards to your earlier open baffle builds.

Because the direction you've gone in is so far from the norm I've been unable to stop thinking about it and this is where I've got to. Congratulations on your originality and the enjoyment you've gained from it.  

Paul