Lots of great content in these replies thanks, i shall read and experiment more in all these matters. i havent found anyway to represent my strange ceiling in a simulator?
I don't know what your ceiling looks like but if it has different heights try and pick something that is a happy medium. It should still give a reasonable result for low frequencies.
I will have a go with that thanks, just to amuse you, pic of ceiling attached, every pic i take reminds me i should clear up and decorate rather than mess around making things........
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The SS Revelator comes in a few variants, the one used in the Fusion is aparently the "M"-version. Compared to the W-versions (W for woofer, M for midrange, I assume) the 18M has lower xmax, higher sensitivity and Fs (to name a few differences). This makes the 18M less suitable (compared to e.g. the 18W) to use in lower frequencies because it runs out of excursion. I'm not in a position to give any recommendations, but I would perhaps not use it much lower than 200 Hz. This could be a problem for the 12-incher if you put it in a folded or H-baffle. Also, if you just want to try out dipoles - what's easier than sawing a couple of holes in a wooden board? 😀
Many thanks, yes i have read this, i have not quite yet grasped what a V baffle is though in contrast to these two. at the moment i feel if i were to experiment i can see using all my current units with an H baffle underneath for the woofer a simple plate for the mid and tweeter. i had thought to leave upper baffle dimensions as per my current boxes, same passive crossover for mid to treble, DSP on bass, although i have to work out how to programme that.
Actually that is what Phoenix looked like about 15 years ago..........
Our posts overlapped, many thanks, i guess your conclusion is similar to mine, current crossover is all set at 200 and 2000, seems to suit, then one big sheet of MDF i can build the two H baffles and the top baffle, normal stack of routing excepted its not a lot of work to find out if its a concept of interest, if it is i can fall down that rabbit hole endlessly, and if it doesn't seem of interest i can put my Fusions back together and listen just as happily as i am while i type this, i might try to master a 3D sketch programme to see what it looks like!
hello, what do you mean the DSP failed? im assuming you used 4x10, but perhaps 2x4 and it distorted?
Maybe that is a language barrier issue, the DSP processor certainly did not "fail". Sorry if I confused you. What I meant was that I transferred the analogue settings to the DSP and it did not sound as good, as in nowhere near as good. The Orion had more low boost that continued below that of the LX521 and it is much better to do that in analogue form than DSP. I also suspect that an improvement to the LX521 could be had by using an analogue boost circuit for at least part of the woofer transfer function.
I used a Najda DSP which I put together myself and was at least on paper a step up from any MiniDSP product, but as I have never tested one of those I can't be certain.
I used a Najda DSP which I put together myself and was at least on paper a step up from any MiniDSP product, but as I have never tested one of those I can't be certain.
Progress?
After lots more thinking I remain enthusiastic to learn if I like the OB sound.
OB enthusiasts and some of your helpful responses suggest to me that with lighter listening tastes I might well enjoy the more open and spatial presentation giving more realism to the performers and this may well be much more “all round the room” than “hot seat”, further that room acoustics and treatment might be less important.
Well, that sounds great to me.
Thinking further about what a satisfyingly good and economic route might be to achieve that I read a lot about active and passive crossovers and SP.
At the end of all that one could conclude that much more specific driver choice etc is quite important and one might end up saying you’ve got to spend the many £K to enjoy or validate that path.
But I started out this path thinking of finding out based on what I already have, I see someone else has built an OB in lockdown using only parts off the shelf.
So I have decided that I would like to learn if I like OB (or some equivalent) as a lockdown project using only parts I have, which basically means the content of my very nice Fusion BAD speakers and wood that's in the workshop. I can re-define that later if it sounds interesting.
So, I thought I would live with one per side 12” bass driver, mount it on an H baffle and drive it with the DSP and Hypex amps I have. This is all configured to cross over at 200Hz in the current set up.
So, if bass is not directional and in room treatment terms passes pretty much straight through 15mm MDF panels, why does the baffle matter so much, how does the bass work as a dipole and why don’t I leave the bass units happily mounted in their ported enclosures as the bass part of this experiment, i.e. a hybrid, which is what a lot of people suggest.
If the mid and tweeter are taken out onto an open baffle next to the current cabinets, the cabinet can sit in the null area to the side.
However the tweeter I have will be a mono pole, so if I mount it on a baffle like it currently is, or a minimal one, it has a sealed back and will be exactly the same……..or wont it? – some posters say that can be fine, others disagree. Some liked monopole tweeters better.
If that’s really the case, all I would be doing would be making the mid driver OB………I can do that, but where does all the difference in sound come from?
Maybe its stage by stage, I could very easily bring the mid and tweeter out onto open baffles alongside the bass in its Fusion cab and see what I’ve got……….
Would value your thoughts!
After lots more thinking I remain enthusiastic to learn if I like the OB sound.
OB enthusiasts and some of your helpful responses suggest to me that with lighter listening tastes I might well enjoy the more open and spatial presentation giving more realism to the performers and this may well be much more “all round the room” than “hot seat”, further that room acoustics and treatment might be less important.
Well, that sounds great to me.
Thinking further about what a satisfyingly good and economic route might be to achieve that I read a lot about active and passive crossovers and SP.
At the end of all that one could conclude that much more specific driver choice etc is quite important and one might end up saying you’ve got to spend the many £K to enjoy or validate that path.
But I started out this path thinking of finding out based on what I already have, I see someone else has built an OB in lockdown using only parts off the shelf.
So I have decided that I would like to learn if I like OB (or some equivalent) as a lockdown project using only parts I have, which basically means the content of my very nice Fusion BAD speakers and wood that's in the workshop. I can re-define that later if it sounds interesting.
So, I thought I would live with one per side 12” bass driver, mount it on an H baffle and drive it with the DSP and Hypex amps I have. This is all configured to cross over at 200Hz in the current set up.
So, if bass is not directional and in room treatment terms passes pretty much straight through 15mm MDF panels, why does the baffle matter so much, how does the bass work as a dipole and why don’t I leave the bass units happily mounted in their ported enclosures as the bass part of this experiment, i.e. a hybrid, which is what a lot of people suggest.
If the mid and tweeter are taken out onto an open baffle next to the current cabinets, the cabinet can sit in the null area to the side.
However the tweeter I have will be a mono pole, so if I mount it on a baffle like it currently is, or a minimal one, it has a sealed back and will be exactly the same……..or wont it? – some posters say that can be fine, others disagree. Some liked monopole tweeters better.
If that’s really the case, all I would be doing would be making the mid driver OB………I can do that, but where does all the difference in sound come from?
Maybe its stage by stage, I could very easily bring the mid and tweeter out onto open baffles alongside the bass in its Fusion cab and see what I’ve got……….
Would value your thoughts!
Just try it yourself! A learning project. You can use two normal tweeters back to back too.
I had three different mid-tweeter combos before the final version.
And now hurry, corona restrictions won't last long!
I had three different mid-tweeter combos before the final version.
And now hurry, corona restrictions won't last long!
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Dipoles can be oriented to make use of their directivity and if done well some traditional room treatments would be unnecessary, this doesn't mean that room acoustics or treatment are not considerations to get the best result though.
There are a few options that you can try with the parts that you have and like Juhazi says trying is a good way to find out what you like, not everyone likes the same.
Keeping the ported woofer and putting the mid on an open baffle is likely to be a mishmash of directivities but it will be different and maybe you will like it.
With a single woofer H or U baffles are options and you can try the difference between dipole and cardioid if you damp the back of the U.
The baffle type and size does make a difference, the why is not a very simple thing to explain in one line, plenty of in room measurements and papers on the subject to demonstrate the differences. Just search dipole vs monopole. Below the transition region the room is in control so finding something to work with it rather than against it is advisable.
For the first try you could use a baffle the same width as your fusion as that will make the existing crossover work better. The Dipole EQ etc. can be added from the Hypex DSP, John K has a page on Hybrid Design that might be helpful.
Hybrid Design
So thinking is that i will do that soon now. First i will make a small baffle for the mid and tweeter. the Fusion baffle top is asymmetric and i thought to make my open baffle symmetrical of the same as the short dimensions from the original, unless there is an immediate reason to make it asymmetric like the original...... That would bake my top baffle 250x355mm, mounted in mid air at the same height as currently on a frame of some sort!
Many thanks to all for your gentle style and interest!
Have you read this? It will give you a lot of good ideas for your first OB
Fast, fun, Inexpensive OB project
Fast, fun, Inexpensive OB project
I have read it now, and many thanks, there are lots of projects out there.
So mine will be different again, if it goes anywhere that sounds interesting i will post updates.
So mine will be different again, if it goes anywhere that sounds interesting i will post updates.
Inherent resistance gradually faded and i made a top baffle, same as Fusion narrow side, one plays, glue drying on the other (the UPS is not relevant, just a weight on the base of the stand!), just took the wires straight out the baffle of the fusion as you can see, more exciting than many lockdown activities..........more soon, mike
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I completed my first OB experiment! - Fusion box bass linked to OB mid treble, all the wiring the same.
Indeed its different, and in some ways nicely so, more open out in the air sound, higher vocals, cymbals more open, the mid treble is more apparent and lighter, which i like, there is some tolerance of imaging moving round the room front to back but only a couple of feet side to side.
The Fusion itself sounds notably smoothly integrated, this, perhaps not surprisingly, does not, either that, or there's more accuracy there now that changes things.......anyway, an interesting first experiment, i will keep listening to it for a while and see if it leads me further down the OB path....
I am unable to discern and describe different aspects of sound as well as lots who post, so i have three different principles alongside each other, monople tweeter, dipole mid perhaps and ported box bass, i cannot attribute any particular sounds to those different areas.
pic attached, bits everywhere in the room but here are my OB panels in place.
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Nice tight twisted wires 🙂 You don't want the absorbtion behind the speakers, if that's what those panels are?
Yes that's absorption behind, the corners are limp mass absorbers (one with its white cover, the other without) and they're well fixed, but shouldn't be doing anything other than bass, but the rest (broadband) i will move and try again.
I have been listening a while now and all sorts of percussion is more apparent than it was, it definitely has some appealing aspects.