Hei Stig,
have you tried to place the baffle around bass drivers without actually touching them ? For LF a small gap won't matter much, especially if you use say sponge material used for sealing doors/windows. You still hang the driver by the chain/wire so there is no direct vibration transfer to the baffle, yet you gain low end by increasing D-eff (lowering F equal). Baffle can also be made as lightweight sandwich (pushing the resonances much higher from the driver operating range) as it doesn't have to be structural anymore. Just a thought ...
Bratislav
have you tried to place the baffle around bass drivers without actually touching them ? For LF a small gap won't matter much, especially if you use say sponge material used for sealing doors/windows. You still hang the driver by the chain/wire so there is no direct vibration transfer to the baffle, yet you gain low end by increasing D-eff (lowering F equal). Baffle can also be made as lightweight sandwich (pushing the resonances much higher from the driver operating range) as it doesn't have to be structural anymore. Just a thought ...
Bratislav
I have an other (expensive..) idea for the midbass. What about four 8" Seas Excel ? If I attach them to each other, where two drivers are facing backwards, there is room for them below the mid/tweeter cluster too. The dipole peak will come a lot higher than a 12", so I wouldnt expect it to go as low in the bass as two 12"
You might also try a soft, non-resonant material for a baffle and have it friction fit around the driver. For example, the foam-like material that is often used in packing small drivers, the kind where a cutout for the driver is bored into the material. I once used one that a tweeter was packed in for a small baffle and it worked very well just friction fit over the driver.
Seas Excel Vs 12' or 15' low mid
Hi Stig Erik,
I am currently experimenting with the 60Hz to 400Hz frequency band as well.
I have had great results with the Seas 8' in a VPL baffle, but after reading about your latest results it prompted me to try the 8' Seas in free air.
Unfortunately it dropped off the scale (not the bass cabinet!) i.e. it was about 20dB down in level compared to the Manger, previously it was within 1dB or 2dB of the Manger level.
I really don’t believe in heavy Eq’ ing, i.e. any more than 6dB or 7dB boost and I think it’s better to change the drivers / baffle rather than increase the EQ.
Also I believe that it’s very important never to allow ( or force) any driver to move more than about 50% of its X Max. This is especially important in the lower mids and bass. i.e. if a bass driver is pumping in and out 8mm or 9 mm and its X Max is 10mm, change the design and use two drivers ( or 4 if you are already using two) or increase the Sd by moving up a size, 12’ to 15’ or
15' to 18 etc.
This all brings in the balances and compromises of good ; point source ( one big driver) Vs bad ; comb filtering, driver tolerance / mismatch when using 2 or more drivers, and cost.
Also remembering voice coil to Sd ratio and Mms to Bl ratio.
One conclusion I am now sure of is that reducing beaming / broad of axis even response is important, but, absolutely not as important compared to minimising cone movement and minimising thermal compression.
These last two points are almost one and the same as the very best of the big pro drivers all have 4inch, 5 inch, or 6 inch (!) voice coils with very high BL, low Mms and therefore are very efficient ( relatively speaking i.e. 3% to 4% instead of 0.5% to 1% audiophile stuff) and never even approach their thermal compression limits in domestic use.
I will take some pics and post them tomorrow to show you the set up. The Mangers are in 25Kg solid wood horns, front loaded with no rear absorbers ( at the moment...) and I am up to 93dB / 94dB sensitivity.
The bass is handled by the superb Beyma SM115/K in a VPL baffle.
The next stage is to try a pair of really great Precision Devices 15 inch 158 which are even faster and lower thermal compression than the A. E. TD15M.
They might be able to handle no baffle, but I suspect a very slim baffle with shallow VPL wings will be the way to go.
Time will tell and I will keep you updated...!
Cheers
Derek.
Hi Stig Erik,
I am currently experimenting with the 60Hz to 400Hz frequency band as well.
I have had great results with the Seas 8' in a VPL baffle, but after reading about your latest results it prompted me to try the 8' Seas in free air.
Unfortunately it dropped off the scale (not the bass cabinet!) i.e. it was about 20dB down in level compared to the Manger, previously it was within 1dB or 2dB of the Manger level.
I really don’t believe in heavy Eq’ ing, i.e. any more than 6dB or 7dB boost and I think it’s better to change the drivers / baffle rather than increase the EQ.
Also I believe that it’s very important never to allow ( or force) any driver to move more than about 50% of its X Max. This is especially important in the lower mids and bass. i.e. if a bass driver is pumping in and out 8mm or 9 mm and its X Max is 10mm, change the design and use two drivers ( or 4 if you are already using two) or increase the Sd by moving up a size, 12’ to 15’ or
15' to 18 etc.
This all brings in the balances and compromises of good ; point source ( one big driver) Vs bad ; comb filtering, driver tolerance / mismatch when using 2 or more drivers, and cost.
Also remembering voice coil to Sd ratio and Mms to Bl ratio.
One conclusion I am now sure of is that reducing beaming / broad of axis even response is important, but, absolutely not as important compared to minimising cone movement and minimising thermal compression.
These last two points are almost one and the same as the very best of the big pro drivers all have 4inch, 5 inch, or 6 inch (!) voice coils with very high BL, low Mms and therefore are very efficient ( relatively speaking i.e. 3% to 4% instead of 0.5% to 1% audiophile stuff) and never even approach their thermal compression limits in domestic use.
I will take some pics and post them tomorrow to show you the set up. The Mangers are in 25Kg solid wood horns, front loaded with no rear absorbers ( at the moment...) and I am up to 93dB / 94dB sensitivity.
The bass is handled by the superb Beyma SM115/K in a VPL baffle.
The next stage is to try a pair of really great Precision Devices 15 inch 158 which are even faster and lower thermal compression than the A. E. TD15M.
They might be able to handle no baffle, but I suspect a very slim baffle with shallow VPL wings will be the way to go.
Time will tell and I will keep you updated...!
Cheers
Derek.
Updates again..
Think I'll keep the two 12" woofers, they sound great, and can be crossed over lower than than four 8". Currently, I cross over as low as 50 Hz. There is 14 dB EQ centered around 55 Hz. Even with that much EQ, I dont have any large cone excursions on the 12" woofers, and I like to boost the low end quite a lot in my target EQ curve as well.
And - I have 21" H-baffle subs! The bass quality from those is.... my goodness.... why on earth do we think boxed woofers can sound good?? Those H-baffles integrates very nice with my room, no need for room correction EQ at all. My old closed box subs required 10-15 dB EQ at several frequencies to measure anywhere close to flat, but they never sounded flat. The H-baffles do!
With a rather large amount (24 dB...) of EQ centered around 27 Hz, they measure flat in listening position down to 30 Hz, -10 @ 20 Hz, -6 @ 23 Hz. Not bad.
Think I'll keep the two 12" woofers, they sound great, and can be crossed over lower than than four 8". Currently, I cross over as low as 50 Hz. There is 14 dB EQ centered around 55 Hz. Even with that much EQ, I dont have any large cone excursions on the 12" woofers, and I like to boost the low end quite a lot in my target EQ curve as well.
And - I have 21" H-baffle subs! The bass quality from those is.... my goodness.... why on earth do we think boxed woofers can sound good?? Those H-baffles integrates very nice with my room, no need for room correction EQ at all. My old closed box subs required 10-15 dB EQ at several frequencies to measure anywhere close to flat, but they never sounded flat. The H-baffles do!
With a rather large amount (24 dB...) of EQ centered around 27 Hz, they measure flat in listening position down to 30 Hz, -10 @ 20 Hz, -6 @ 23 Hz. Not bad.
An externally hosted image should be here but it was not working when we last tested it.
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What is "Kraut-Rock"???
They can't play very loud below 35 Hz, no surprise really. Playing bass-heavy music very loud works well without stressing the driver, but if there's something serious happening below 30 Hz I run into problems.
The H-baffles outputs almost nothing but harmonic distortion and noise below 25 Hz. So - if I want response to 16 Hz or so, I will need closed box subs in addition. Listening tests will tell if I'm missing anything...
If I want to impress my guests with chest pounding bass, I'll will just switch to a pair of 2x15" bass reflex speakers!
They can't play very loud below 35 Hz, no surprise really. Playing bass-heavy music very loud works well without stressing the driver, but if there's something serious happening below 30 Hz I run into problems.
The H-baffles outputs almost nothing but harmonic distortion and noise below 25 Hz. So - if I want response to 16 Hz or so, I will need closed box subs in addition. Listening tests will tell if I'm missing anything...
If I want to impress my guests with chest pounding bass, I'll will just switch to a pair of 2x15" bass reflex speakers!
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I have PHL2460(spl:96dB) a cheaper version of PHL1120, I will be getting the HI-VI RT8II (spl: 96dB and selling at US$84). I think it will complement the PHL1120.
Anything that style form the Germans - "Kraftwerk" for example.
http://de.wikipedia.org/wiki/Krautrock
scroll down to "Bedeutende Vertreter"
English version
http://en.wikipedia.org/wiki/Krautrock
Michael
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Oh well, there was something that started to complain at insane SPL levels last night, but it wasn't the 21" H-baffles, but the twin 12" woofers. Ok, so I just moved the XO up to 70 Hz - problem solved!
I also moved the H-baffles somewhat towards the front wall. There was NO change in frequency response, would you belive that?! With box subs, we would have seen large changes. The only thing that happended was a little less level because of the greater listener to speaker distance.
Here's a new picture of the setup:
I also moved the H-baffles somewhat towards the front wall. There was NO change in frequency response, would you belive that?! With box subs, we would have seen large changes. The only thing that happended was a little less level because of the greater listener to speaker distance.
Here's a new picture of the setup:
An externally hosted image should be here but it was not working when we last tested it.
Thank you very much for this report, Erik. It is very enlightening.
I'm wondering (for my next project) whether to go with 2x 12" or 2x 10", not baffleless, but with little baffles. I think I have to run some simulations with the edge again.
Which is the high XO point for the 12"?
Cheers
OK, here's a list of whats playing now:
Drivers:
Beyma 21SW1600nd in H-baffle 25-70 Hz
2x Beyma 12P1000nd 70-350 Hz
2x Seas W15CH001 350-1700 Hz
Mundorf AMT 2340 without frontplate 1700 Hz ->
Woofer H-baffle is 60x60x60 cm
Amplifiers of my own production, based on Icepower standard modules:
Tweeter: 60W / 8 ohm
Midranges: 450W / 4 ohm
Woofers: 1200W / 4 ohm
Subwoofers: 1200W / 4 ohm
XO:
Computer software: Console, Waves LinEq, Waves Paragraphic
Computer audio interface: RME Fireface 800
DAC: Digital Audio Denmark AX24 (8-channels)
Source:
Squeezebox
Cables: yes
Drivers:
Beyma 21SW1600nd in H-baffle 25-70 Hz
2x Beyma 12P1000nd 70-350 Hz
2x Seas W15CH001 350-1700 Hz
Mundorf AMT 2340 without frontplate 1700 Hz ->
Woofer H-baffle is 60x60x60 cm
Amplifiers of my own production, based on Icepower standard modules:
Tweeter: 60W / 8 ohm
Midranges: 450W / 4 ohm
Woofers: 1200W / 4 ohm
Subwoofers: 1200W / 4 ohm
XO:
Computer software: Console, Waves LinEq, Waves Paragraphic
Computer audio interface: RME Fireface 800
DAC: Digital Audio Denmark AX24 (8-channels)
Source:
Squeezebox
Cables: yes
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