No.......what I found strange is you suggesting to someone earlier on that OB/Dipole bass has lower harmonic distortion than sealed systems based on your observations, that's all. Quite an empirical statement don't you think?......or maybe you don't...I have no idea what runs through your head sometimes given all these experimental builds? lol
Would you rather not have your work criticized by your peers?
Ok, I will correct what I said earlier. I should have said for sealed subs that are sized with an excessively small cabinet, may exhibit more HD than an appropriately sized cabinet, all else being equal. In my experience with two undersized sealed systems, the drivers exhibited a higher level of HD relative to an OB running at the same drive level when I placed them inside small sealed cabinets.
As I write this, I am listening to my stereo system playing Pink Floyd's Delicate Sound of Thunder CD: it sounds fantastic. The dynamic range on this speaker is very good - from soft-softs to the louder-louds, there is a good range. Interesting how a foam core uTrynergy can be used on one side and a plastic WG wooden box version can be on the other side and they are balanced (well, I balanced them via mic within a 1 dB or so over their range so maybe should not come as a surprise).
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What matters most isn't what I think or you say, but what you truly believe.......integrity above all else which your body of work indicates you have in spades......I just might not always agree with your conclusions. LOL.
I do have a sealed cabinet that doesn't have excessive distortion. It's a 24 liter used with an RS225-8 for my 10F/8424 FAST setup. That one was sized to have a Q somewhere in the mid 0.5 range and it works just fine. It's also a nice driver known for low distortion.
I was just perplexed by the last couple of times I tried to stick a driver in an excessively small box. I did it before with a real cheap high Qts $5 buyout 6.5in polycone woofer with the Trynergy (two of them were put in an 8 liter box) and that worked well without excessive distortion but probably because the box was a little leaky (no gaskets) so no high pressure build up.
I was just perplexed by the last couple of times I tried to stick a driver in an excessively small box. I did it before with a real cheap high Qts $5 buyout 6.5in polycone woofer with the Trynergy (two of them were put in an 8 liter box) and that worked well without excessive distortion but probably because the box was a little leaky (no gaskets) so no high pressure build up.
I agree that for the same voltage input OB may have less distortion due to lack of asymmetric excursion generating HD.
But is this maintained when the constant in comparison is SPL?
I'm sceptical on that front lol.
Now a DCR like you have built....well....different matter altogether. That broader loading I'd expect to level HD nicely, until below Fb.
Again anecdotally, these discussions, and the attempted rationalisation and quantification of phenomena that seem to be counter intuitive, they remind me of observations that were written in Weem's book. Subjective quality of bass, boom, or bass anemia and the system Q. Whilst we all design to theoretical ideals, there is always a case which confuses the he'll out of the best of us. (He describes a 3 way system with Q of 1.4 and how he was pleasantly surprised at the lack of boom. When I ran the numbers the box was less than half the 'optimal' volume. In another design using a 8" woofer, his observations were the opposite; despite a system Q of 0.8 or so, he judged the bass to be too "full")
It could well be the case that you are observing a similar thing. OR that what Weems observed was NOT purely a system Q effect.
FWIW I listened to a lopsided stereo for years (identical drivers, different XOs). Once you become accustomed, it sounds balanced. And it only takes a few minutes to become accustomed.
Our brains are fantastic processors of instinctual senses, just not so great at rationalising the cause of our joy response to music we love
But is this maintained when the constant in comparison is SPL?
I'm sceptical on that front lol.
Now a DCR like you have built....well....different matter altogether. That broader loading I'd expect to level HD nicely, until below Fb.
Again anecdotally, these discussions, and the attempted rationalisation and quantification of phenomena that seem to be counter intuitive, they remind me of observations that were written in Weem's book. Subjective quality of bass, boom, or bass anemia and the system Q. Whilst we all design to theoretical ideals, there is always a case which confuses the he'll out of the best of us. (He describes a 3 way system with Q of 1.4 and how he was pleasantly surprised at the lack of boom. When I ran the numbers the box was less than half the 'optimal' volume. In another design using a 8" woofer, his observations were the opposite; despite a system Q of 0.8 or so, he judged the bass to be too "full")
It could well be the case that you are observing a similar thing. OR that what Weems observed was NOT purely a system Q effect.
FWIW I listened to a lopsided stereo for years (identical drivers, different XOs). Once you become accustomed, it sounds balanced. And it only takes a few minutes to become accustomed.
Our brains are fantastic processors of instinctual senses, just not so great at rationalising the cause of our joy response to music we love
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How did a DCR enter into this? If you are talking about this one with the TC9FD, it does indeed have low and level HD (no broad peak at circa 60 to 80Hz like most of my sealed boxes) but I thought that was mostly because it was measured at a small signal level of 72dB (which was about the volume I intended to use it at as a nearfield). Byrtt actually has this speaker now but has put a 10F/8424 in it as a "holder" for his transient perfect FAST system with a Monacor woofer.
http://www.diyaudio.com/forums/full-range/252627-viva-la-vifa-curvy-cabinet-dcr-tc9fd.html
Here was the HD from the TC9FD DCR - I never knew DCR's had the potential for lower HD:
http://www.diyaudio.com/forums/full-range/252627-viva-la-vifa-curvy-cabinet-dcr-tc9fd.html
Here was the HD from the TC9FD DCR - I never knew DCR's had the potential for lower HD:
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Originally Posted by weltersys
This (slot load) arrangement can also be done as push-pull to reduce even order HD.
http://www.diyaudio.com/forums/subwoofers/191833-push-pull-vs-normal-distortion-compared.html
Further reduction of even order would have occurred if the drivers would have shared a plenum.
Whether reduction of even order distortion is desirable is a matter of opinion 😉.
On the subject of distortion and too-small enclosures, my dual 15" PPSL "shoehorn" have higher distortion for a given LF output than a pair of Lab 12" in the same enclosure (less the volume occupied by the plenum), in spite of the push pull arrangement.
http://www.diyaudio.com/forums/subwoofers/255010-compact-2x15-ppsl-using-dayton-pa385-8-drivers.html
The trade off between the greater upper output of the 15"s, and the cleaner LF output of the Lab12"s was a decision I probably would not make for home theater use, but works well for PA.
Gentleman, choose your weapons 😉 .
This (slot load) arrangement can also be done as push-pull to reduce even order HD.
Non-linear forward and rear cone motion occurs, especially on speakers with poorly designed magnetic and suspension systems. Even with well designed speakers, the reduction of even order harmonic distortion was definitely proven:
http://www.diyaudio.com/forums/subwoofers/191833-push-pull-vs-normal-distortion-compared.html
Further reduction of even order would have occurred if the drivers would have shared a plenum.
Whether reduction of even order distortion is desirable is a matter of opinion 😉.
On the subject of distortion and too-small enclosures, my dual 15" PPSL "shoehorn" have higher distortion for a given LF output than a pair of Lab 12" in the same enclosure (less the volume occupied by the plenum), in spite of the push pull arrangement.
http://www.diyaudio.com/forums/subwoofers/255010-compact-2x15-ppsl-using-dayton-pa385-8-drivers.html
The trade off between the greater upper output of the 15"s, and the cleaner LF output of the Lab12"s was a decision I probably would not make for home theater use, but works well for PA.
Gentleman, choose your weapons 😉 .
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+1^^^
I'd love/hate to measure my system and find out how good/bad the HD is at sub 40Hz @ 90dB lol.
I'm sure I would be adequately pleased/disappointed in the output from what are otherwise good very low THD drivers 🙂
X,
I only mention DCR as you clearly used the concept to affect broader bass loading, and as a consequence I'd expect the HD to also be reduced. (I wasn't actually familiar with the SPL you designed for). I eel confident that the HD would hold up under harsher treatment than 78dB though 😀
I'd love/hate to measure my system and find out how good/bad the HD is at sub 40Hz @ 90dB lol.
I'm sure I would be adequately pleased/disappointed in the output from what are otherwise good very low THD drivers 🙂
X,
I only mention DCR as you clearly used the concept to affect broader bass loading, and as a consequence I'd expect the HD to also be reduced. (I wasn't actually familiar with the SPL you designed for). I eel confident that the HD would hold up under harsher treatment than 78dB though 😀
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.....Byrtt actually has this speaker now but has put a 10F/8424 in it as a "holder" for his transient perfect FAST system with a Monacor woofer.
http://www.diyaudio.com/forums/full-range/252627-viva-la-vifa-curvy-cabinet-dcr-tc9fd.html
Yes thanks and lucky me they flew far east from US without any sign of jet lag, a 10F into that enclosure have nearly same main resonance as in free air as seen below where blue is free air and yellow is DCR.
Could be wrong but from discussions regarding use of sealed box for low frq duty say 200Hz and below where some air will be moved compared to higher frq it could look like don't go high Q alignment, still its possible to use smaller volumes this way but drivers TS data need to support smaller volume.
Attachments
You have a great point here, and I forgot to do it in this case - but always a good idea to model the driver in a standalone rear sealed chamber of equivalent volume as intended use in whatever alignment on front of cone (such as band pass) to see how the driver's TS parameters deal with smaller volume from looking at the Q overshoot. In some cases I was using that overshoot and massaged it with a high pass filter that would then bring up the SPL efficiency at the bass around 90Hz. On paper that works but in practice it is forcing driver to operate in a place it doesn't like with lots of air pressure compression and concomitant higher distortion of stuffing a driver in too small a box.
X have you got four unused DC200-8 laying around then wonder if something ala 5th elements stands could hold two of each and work as subs below 50-80Hz area, if you happen like it then let Jessmann do the woodwork : )
Pictures borrowed from this thread where a B&W FST mid have phase plug removed to be a waveguide for Aura NT1 with little mod http://www.htguide.com/forum/showthread.php?38667-B-amp-W-FST-mid.
Pictures borrowed from this thread where a B&W FST mid have phase plug removed to be a waveguide for Aura NT1 with little mod http://www.htguide.com/forum/showthread.php?38667-B-amp-W-FST-mid.
Attachments
That's a nice curved wall box very much in the spirit of B&W 800's series. That custom FST coax is really a great idea and I am sure it sounds great. I wonder how low the FST goes though? Maybe 400Hz?
I only have 2 of the DC200's at present. They just don't have the low distortion motors that a woofer needs. Probably fine for a vented reflex alignment or even a TL. I had great luck with the smaller DC130 in a TL.
I think eventually bass will be from my custom folded bass horn which I have at present one unit. A stereo will arrive one of these days via Jessman. That will have me covered from 35Hz to 200Hz.
I only have 2 of the DC200's at present. They just don't have the low distortion motors that a woofer needs. Probably fine for a vented reflex alignment or even a TL. I had great luck with the smaller DC130 in a TL.
I think eventually bass will be from my custom folded bass horn which I have at present one unit. A stereo will arrive one of these days via Jessman. That will have me covered from 35Hz to 200Hz.
So. I painted up the second speaker this evening. I have been listening in stereo for the last few hours.
I have got some pretty good DIY speakers to compare these to. I have the high end sealed three ways I made - with SB tweeter/12MU scanspeak mids and scanspeak woofers complemented with multi subs, a few single driver speakers, the WA prestige you can see in the picture above with very high end drivers and have had numerous shop bought 'Hi-Fi' speakers and studio monitors such as the Focal CMS....that is where I am coming from...
I have experienced high fidelity, and many times experienced the 'they are here' phenomenon - i.e. the band is in the room etc.
I have never before experienced to such a degree the 'I am there' feeling.
If you have the space for these speakers - I admit these are not 'bookshelf' speakers! - these are really something quite special.
Every recording I listen to, I can hear the venue, the recording process etc. etc. greater than ever before.
I don't know if it is the excellent phase, step response, controlled directivity - removing the room effects, low HD from 30 Hz right up, or the point source behavior of the synergy design, but these speakers are amazing.
If I listen to a recording made in a large space and close my eyes, I am there. The detail retrieval is amazing - I am comparing these things to the Volt VM752 domes and scanspeak 12MU mids directly...
I was only going to listen for 30 mins or so to get an idea of the sound, I am still here two hours later.
Seriously. I am blown away. I also am now seriously doubting the need for a sub cabinet. The bass is extraordinary.
OK I gotta get back to my albums. 😀
I have got some pretty good DIY speakers to compare these to. I have the high end sealed three ways I made - with SB tweeter/12MU scanspeak mids and scanspeak woofers complemented with multi subs, a few single driver speakers, the WA prestige you can see in the picture above with very high end drivers and have had numerous shop bought 'Hi-Fi' speakers and studio monitors such as the Focal CMS....that is where I am coming from...
I have experienced high fidelity, and many times experienced the 'they are here' phenomenon - i.e. the band is in the room etc.
I have never before experienced to such a degree the 'I am there' feeling.
If you have the space for these speakers - I admit these are not 'bookshelf' speakers! - these are really something quite special.
Every recording I listen to, I can hear the venue, the recording process etc. etc. greater than ever before.
I don't know if it is the excellent phase, step response, controlled directivity - removing the room effects, low HD from 30 Hz right up, or the point source behavior of the synergy design, but these speakers are amazing.
If I listen to a recording made in a large space and close my eyes, I am there. The detail retrieval is amazing - I am comparing these things to the Volt VM752 domes and scanspeak 12MU mids directly...
I was only going to listen for 30 mins or so to get an idea of the sound, I am still here two hours later.
Seriously. I am blown away. I also am now seriously doubting the need for a sub cabinet. The bass is extraordinary.
OK I gotta get back to my albums. 😀
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Drum roll.... The question is do they impress you more than the big Wilmslow Audio 3 ways they are using as stands?
Edit : we cross posted, never mind you answered above.
It's all of the above all together in one package. Still quite a compact package when compared to what you are contrasting them to.
Congratulations on an awesome build and in record time for a first-off prototype built from plans cobbled together in real-time. I thought they would sound good but that is so cool that you think they sound better than all your other speakers!
Well done man. 🙂
One more thought: I wonder how much of the "you are there" feeling is the flat phase and quasi transient perfect Harsch XO. If you were to switch to a traditional LR XO that you would have used otherwise, how much of the magic is lost (or still there)? Don't have to do it right away - enjoy your new creations for a while. You deserve it.
Happy listening.
Edit : we cross posted, never mind you answered above.
It's all of the above all together in one package. Still quite a compact package when compared to what you are contrasting them to.
Congratulations on an awesome build and in record time for a first-off prototype built from plans cobbled together in real-time. I thought they would sound good but that is so cool that you think they sound better than all your other speakers!
Well done man. 🙂
One more thought: I wonder how much of the "you are there" feeling is the flat phase and quasi transient perfect Harsch XO. If you were to switch to a traditional LR XO that you would have used otherwise, how much of the magic is lost (or still there)? Don't have to do it right away - enjoy your new creations for a while. You deserve it.
Happy listening.
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Horn.ell.a
Hello I am new of this forum, I would ask if anyone has tested Horn.ell.a software.
I would buy it to develop a special elliptic horn for hi-fi systems.
Hello I am new of this forum, I would ask if anyone has tested Horn.ell.a software.
I would buy it to develop a special elliptic horn for hi-fi systems.
I've been following this development with great interest. Is the build tested and described bushmeister above the final version ? Is this meant to be collaborative open source? Will the cad files for 3d printing the mid adapters and the crossover design, etc be available so others could build them?
Pardon the multiple questions. I'm excited!
Sent from my GT-I9505 using Tapatalk
Pardon the multiple questions. I'm excited!
Sent from my GT-I9505 using Tapatalk
Everything on this thread has been discussed and explained, but it's spread throughout the many pages. I think Bushmeister said he would summarize his design soon once he can pull himself away from listening to his new speakers.
The main points are:
- 18Sound XT1464 waveguide with qnty 2 bandpass holes of 60mm dia for ea woofer
- SB Acoustics SB65WBAC25-4 fullrange 2.5in driver for waveguide mid/tweet
- SB Acoustics SB23NRXS45-8 8in woofer driver for bass bandpass injection (qnty 2)
- Sealed enclosure of size specified above (I don't recall offhand) - with lots of bracing, felt damping, rockwool, and sorbothane vibration absorption pads
- miniDSP 2x10 to provide XO and EQ, set to Harsch XO at 500Hz, not sure what Bushmeister uses for amps.
For my build, I used different waveguide and woofers, but the SB65 is a critical part to obtain smooth operation over 500Hz to 20kHz:
- Faital Pro LTH142 waveguide with qnty 2 bandpass holes per woofer (with equivalent CSA of 29mm hole ea), and 1in thick throat adapter for SB65
- Dayton Audio RS180P-8 woofers (qnty 2)
- Sealed enclosure with about 31 liters volume (*but I suspect a larger one would make it sound better) with eggcrate sound absorbent foam on all internal walls and fiberglass stuffing.
- miniDSP 2x4 with 600Hz Harsch XO and all TPA3116D2 class D amps powered by 19v laptop bricks. You will need a calibrated mic (UMIK-1 is what I use) and you will need REW in order to dial in your EQ and XO accurately.
Regarding 3d printed parts - they are specific to the LTH142, which I am not sure if you are using. Sorry, but I can't provide the 3d stl files for the parts I used. I will gladly give you tips on how to model it in CAD though.
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