An interesting build. I expect those Neos sound good. How have you mounted the bass unit. Details of crossover and any EQ would be interesting.
the subwoofers in the vicinity of the turntable without any attempt of isolation from vibrations ....Lol! I appreciate your concerns but don't worry.
The subwoofers are dual opposed with connecting rods. Due to mechanical coupling and force cancellation they are completely vibration free (I reported the build here years ago!)
Also the turn table is a DIY build. It has a neodymium ring magnet floating platter and is on sorbothane hemispheres. Also the sheets of granite are isolated from each other. There is no effect of the subwoofer location on the turntable I can identify and believe me I have moved them about over the years!
The subwoofers are dual opposed with connecting rods. Due to mechanical coupling and force cancellation they are completely vibration free (I reported the build here years ago!)
Also the turn table is a DIY build. It has a neodymium ring magnet floating platter and is on sorbothane hemispheres. Also the sheets of granite are isolated from each other. There is no effect of the subwoofer location on the turntable I can identify and believe me I have moved them about over the years!
The bass units and hanging on paracord. Resonant frequency of them hanging appears to be well below 10hz so they transmit virtually no vibration into the frame, and having looked at all the options this is compelling reason for having no baffle on them (besides the excellent dipole response when nude ) - otherwise you have to deal with heavy damped and braced baffles to deal with the vibrations.
Crossovers are currently 100, 800, and 3500, all 24LR but this is still up for experimentation.
I am using minidsp 4x10HD at the moment so EQ is easy. The deltalites need a lot below 300hz obviously due to there being no baffle. But with EQ I can flatten all drivers well above and below crossover points then simply apply normal LR slopes to get textbook summation (I love DSP!).
They measure incredibly well from a dipole point of view and I seem to have almost perfect dipole measurements for most of their range.
Placement needs to be at least 1-2 meters from the front wall behind with decent in-toe to the listener - placing the rear reflections even more distance as the rear then aims into the corners.
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Which was the best sounding build (..and in what respects)?
What a question!!!
Well I hate answering questions like this usually as it's a bit like 'whats your favorite single malt?' or something......but.....
Hmmm:
My single driver builds have lovely clarity and simplicity and do have excellent soundstaging, however they tend to be SPL limited, and do not have the dynamics of my multi driver builds.
My most conventional multiway builds all sounded the most like 'normal box speakers' - I went to great lengths early on in my DIY journey to optimize these builds with sorbothane driver mounting, angled baffles, and CLD bracing and baffles (see some of my older builds here). But regardless they didn't come out as well as my more unusual later builds.
My synergy builds (also documented on here) combined unusual enclosure design (spheres) with a two way small full range driver mounted to a pretty decent commercial horn that I then synergised.
They always measured incredibly well, and sounded excellent, but for me were just too much like a decent pair of headphones in a lot of ways. Also they didn't have the clarity of my later builds - whether this was a driver issue or implementation I could never work out - diffraction from the woofer ports? Poor horn design, or the full range driver not being up to the job?....anyway I was left underwhelmed by them.
Then came my multiple spherical build (you can see them in the background behind the open baffles). This used expensive drivers (volt, scanspeak, SBacoustics sartori) in stacked spheres with the idea of minimising diffraction and cabinet colouration.
They sounded incredible - and I have lived with them for 5-6 years now I think, without wanting anything more - by far the best sounding speakers I have made....
But, I wanted to try open baffles.....so.....
Frankly I am shocked. I have always been skeptical of the open baffle concept (how can firing as much energy away from the listener be sensible??) - think of all those reflections and miscues etc. etc.
I was aware my use of nude drivers would render enclosure diffraction (and in fact diffraction from the drivers themselves) virtually negligible, but I was completely unprepared for the way these things disappear. Even hard panned sounds are not easily located.
I was also unprepared for the detail retrieval and clarity of them. I thought they would sound more 'woolly' and softer with a pleasing yet more spread soundstage. I thought all the rearward energy and added reflections would muddy audio cues and whilst increasing envelopment and ambiance they would be obviously less analytical than my synergy horns and spherical mutiways. I also thought they would not give an accurate insight into a recording as you are essentially 'adding' reverb in a way.....
I was wrong. I still have a lot or experimentation and work to do....but........so far they may be the most 'real life' rendering of a soundscape I have ever heard. I am frankly shocked. I do not know if this is the use of the AMTs from 600-800hz upwards, or the open baffle design or a combination.
It might be because I haven't dialed in my spherical build properly yet - I messed with them accidentally when doing the digital crossovers, or just the whole 'new build bias'.
But I am weirdly disappointed, as I am a shallow individual and I much prefer the look of my bamboo spherical speakers over them (which I find rather industrial ugly - these were really just a prototype build more than anything)...I don't really want to have the opens baffles as my main speakers unless I can make them look a lot nicer!!!
So conclusions......it appears Linkwitz, John K and all the clever people who have been trying to tell us open baffles are the way forward, may have been onto something after all.
My impressions may change over time - they sometimes do, but at present my family and friends who have heard them appear to agree.....
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my 2way OB with ribbon helper, hopefully this is the final iteration. use harsch xo @240Hz
source : dell optiplex playing loseless with foobar2000 or deezer hifi, vlc player for bluray collection
- AD1865 dac with dcb1 preamp
- minidsp 2x4HD to : aragon2004 for 21" woofer and mauropenasa gainclone drives PRV 5mr450-ndy + beston rt002 ribbon tweeter with 3.3uf filter
- behringer nu3000dsp get mono signal from summing opamp after dcb1, then drives 2 dual-opposed sealed subwoofer 4th order @40Hz
in my relatively big room 5x6m with 3.3m concrete ceiling, eventhough my 21" subwoofer have 7mm xmax, it still can't fill the room especially for deep bass. that's where the subwoofer really help, it's mandatory during bluray movie
OB woofer + multiple sealed subwoofer :
my wide lens phone is not good enough, bad vignette can be noticed easily
source : dell optiplex playing loseless with foobar2000 or deezer hifi, vlc player for bluray collection
- AD1865 dac with dcb1 preamp
- minidsp 2x4HD to : aragon2004 for 21" woofer and mauropenasa gainclone drives PRV 5mr450-ndy + beston rt002 ribbon tweeter with 3.3uf filter
- behringer nu3000dsp get mono signal from summing opamp after dcb1, then drives 2 dual-opposed sealed subwoofer 4th order @40Hz
in my relatively big room 5x6m with 3.3m concrete ceiling, eventhough my 21" subwoofer have 7mm xmax, it still can't fill the room especially for deep bass. that's where the subwoofer really help, it's mandatory during bluray movie
OB woofer + multiple sealed subwoofer :
my wide lens phone is not good enough, bad vignette can be noticed easily
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Bushmeister
Thanks for the interesting info on Xover and EQ which confirms what I thought. Your reply to ScottG is also particularly interesting given the variety of loudspeakers you have built and tried along with your description of your subjective relative impressions of them. Worth reading twice I think. I always try to design and build something different rather than just slightly better than my last project. Your approach is a superb example of that.
Thanks for the interesting info on Xover and EQ which confirms what I thought. Your reply to ScottG is also particularly interesting given the variety of loudspeakers you have built and tried along with your description of your subjective relative impressions of them. Worth reading twice I think. I always try to design and build something different rather than just slightly better than my last project. Your approach is a superb example of that.
Suggestion: add some bass actuators to your listening chair.
LOL! those dual opposed stereo subs can already shake the sofa with their output
Further to my previous listening impressions - I have had more time to listen and double check my crossovers - I was right I had reset my sphere multiway crossover to a previous iteration that wasn't optimized - no time compensation for the drivers and a few other under optimized parameters.
So after resetting them to their best the impressions -
Well they haven't changed too much - still incredibly impressed with the open baffles - but I no longer think they are better than my monopole multiways - just different.
The open baffles have less dynamics on really dynamic orchestra stuff for instance - which isn't surprising.
The detail retrieval on both is top notch, but I think the sound staging on the open baffles is slightly deeper and slightly more 3D - I am sure down to the rearward contribution of dipole radiation.
So it is a typical loudspeaker pick your compromise:
1. Sphere multiway monopole build - more dynamic, placed back in the room out of the way and less floor space needed.
2. Nude driver open baffle - less dynamic, more in the room and therefore difficult to locate, but better and more 3D soundstage.
Both have fantastic tone, detail, and sharp imaging - I was surprised by the open baffle imaging as was expecting it to be more diffuse. But I think this could be down to optimization of the crossovers, and phase etc - something much easier to achieve with DSP.
Both speakers are end game for me being the best I have heard, so I am in the very happy position of being able to pick and choose.
The only build left to do is line array.......Probably give me another 5 year though
Possibly a combination of both - but the soundstaging and dynamic differences are only subtle differences - I am powering these with pro audio MC2 amps all obviously fully active, so there is no shortage of power, and they are both very dynamic compared to the average commercial speaker.
I guess I am really trying to pick out differences - part of my quest to build and try all the different speaker types (which reminds me I have forgotten I will have to build an omni at some point too......) as this was the whole point.
They share a lot more in common than any differences.
I do think the AMTs have incredible resolution.
OK putting my cards on the table - I am constantly switching in preference between the two - depending on track, genre, mood etc.
I do wonder if open baffle sound better with life orchestral pieces and 'big pieces' whilst the monopole have the edge with studio pieces and EDM, but before making any more conclusions I will need at least another 6 months of auditioning!
This hobby is just so much fun!
I guess I am really trying to pick out differences - part of my quest to build and try all the different speaker types (which reminds me I have forgotten I will have to build an omni at some point too......) as this was the whole point.
They share a lot more in common than any differences.
I do think the AMTs have incredible resolution.
OK putting my cards on the table - I am constantly switching in preference between the two - depending on track, genre, mood etc.
I do wonder if open baffle sound better with life orchestral pieces and 'big pieces' whilst the monopole have the edge with studio pieces and EDM, but before making any more conclusions I will need at least another 6 months of auditioning!
This hobby is just so much fun!
Electronic music, synthesizers is wonderfull on OB. Actually I love all music on my OBs including death metal. Compared to traditional speakers you will miss some impact, but its still a good compromise. Omni also have some unique features that I miss, this is the very similar image in a very wide area. The imaging never collapse, but the compromize to me was too much. I really missed some dynamics or direct sound.
Some OB dynamic consideration(s)
If an OB – cardioid system has sufficient displacement, you can equal, and in some cases exceed dynamics of nearly all box systems with the possible exception of quality very large horn loaded designs.
Where many OB’s get in dynamic trouble below 70 Hz or so is usually due to not enough cone area and Xmax. (VD - Total Volume Displacement)
A pair of 18” woofers on a 24” wide baffle with an effective wing depth of 12”, assuming an xmax of 10 mm or more peak, is a bit more than a single 15” with the same xmax in a correctly designed B4 enclosure. This is a rough comparison, but close enough.
I am assuming either system has an in room F3 around 30 – 34 Hz with correct crossover. If you run the displacement numbers, the twin 18’s provide VD of 2,400 CC. A single 15” will be around 875 CC. My rule of thumb is an OB requires around 2.4 to 2.6 times the VD compared to a correctly designed ported enclosure to equal or exceed the ported enclosure in terms of dynamics and net output. Cardioid systems will fair better and can have a 1.75 to 2.25 times yield requirement. Again, this is a general value based on many years of experimentation. YMMV!
OB cancellation loses are what we are dealing with. And ported enclosures are notorious interacting with room nodes providing added slam at certain frequencies. Take both outside and the box slam usually goes away and or is greatly attenuated.
So, it gets back to the OB has to be large to compete dynamics wise. But on an equal footing it can compete without the non- linear (room – boom box) penalties.
If an OB – cardioid system has sufficient displacement, you can equal, and in some cases exceed dynamics of nearly all box systems with the possible exception of quality very large horn loaded designs.
Where many OB’s get in dynamic trouble below 70 Hz or so is usually due to not enough cone area and Xmax. (VD - Total Volume Displacement)
A pair of 18” woofers on a 24” wide baffle with an effective wing depth of 12”, assuming an xmax of 10 mm or more peak, is a bit more than a single 15” with the same xmax in a correctly designed B4 enclosure. This is a rough comparison, but close enough.
I am assuming either system has an in room F3 around 30 – 34 Hz with correct crossover. If you run the displacement numbers, the twin 18’s provide VD of 2,400 CC. A single 15” will be around 875 CC. My rule of thumb is an OB requires around 2.4 to 2.6 times the VD compared to a correctly designed ported enclosure to equal or exceed the ported enclosure in terms of dynamics and net output. Cardioid systems will fair better and can have a 1.75 to 2.25 times yield requirement. Again, this is a general value based on many years of experimentation. YMMV!
OB cancellation loses are what we are dealing with. And ported enclosures are notorious interacting with room nodes providing added slam at certain frequencies. Take both outside and the box slam usually goes away and or is greatly attenuated.
So, it gets back to the OB has to be large to compete dynamics wise. But on an equal footing it can compete without the non- linear (room – boom box) penalties.
I agree with John's advice. There is no inherent reason for an OB system to have less impact but I do see a lot of people (who presumably come from box speaker designs) skimping on LF displacement in their OB design. It's not just about max SPL being limited but also about reducing the dynamic compression which results from driving one woofer too hard. For example, in the example below (taken from The Powered Subwoofer Tests | Audioholics ) the woofer's output increases by only 13dB when the input increases by 20dB (@100Hz). That's a very significant loss and should be avoided if at all possible.
2 x 15" or 2 x 18" per side with high linear Xmax capability and an H-frame or similar should be enough for most listening rooms. A naked single 15" with only average linear Xmax may struggle. Of course, YMMV.
Thanks for doing that! Now I have a better understanding.
I have sealed subs below 65Hz and 18" naked OB up to 275Hz, where two OB 8" per side take over. There is slam, but would tend to agree with Kjeldsen that a 15" in a box hits harder. Now I know how I should do to get at the same level. But the wife won't allow two 18" per side on a 24" baffle, per side, in the living room
Nevertheless, the level of bass definition I'm getting has me smiling, and while the impact might not be as high as one 15" in a sealed box that wouldn't be allowed in the living room anyway. And the naked 18" is punchier than a couple of 8" in a box from prior good commercial speakers.
Up to now I was thinking in terms of Sd. The 18" has 1200cm2 which is 5.4 times the Sd of an 8" at 223cm2, but my gut suggested 5x8" in a box would deliver more punch than a naked 18". I guess I should look at VD.