Hello… I’ve been in the silent majority long enough. Over the course of several years now, you have helped me without ever knowing it. Today, I break my silence and join your group. I hope the water is warm. )
Recently, I was fortunate enough to acquire a pair of Aurasound 1808 18” sub drivers; one of which is slated to upgrade the family’s HT. I used Kristian Ougaard’s UniBox 3 to model a vented system at 100 W which I found a 340 L cabinet tuned to 20 Hz seemed to be reasonable. Although the driver is rated at 800 watts and will be driven by a 700 watt/8 ohm Carver amp, I chose 100 watt nominal power as a more pragmatic value – the SOF -- )
The problem is that the Aurasound’s response is only fairly ‘flat’ in the 20 to 40 Hz range, then it continues to slowly ramp up.
20 Hz – 108.6 dB
30 Hz – 109.5 dB
40 Hz – 110.2 dB
50 Hz – 111.1 dB
60 Hz – 112.0 dB
70 Hz – 112.8 dB
80 Hz – 113.5 dB
300 Hz – 117 dB
Now, for HT that’s not all that bad of a thing, right? But for the vast majority of us, we have a one-world HT/music system. And for music, flat is where it’s at – or at least for the most part.
Here is where the North Creek Leviathon question comes into play. The second driver is in possible need of a re-cone kit, which is available from the manufacturer for $150 or so. But, if you look at the specs for the Leviathon (customized 1808), it is clear that George has done his homework. The predicted response for a vented Leviathon for a 300 L cabinet tuned to 18 Hz is spot on -- smaller cabinet, lower tuning and response as flat as a torsion box. Even better would be 340 L at 17 Hz. I can send him my driver to have it reconditioned into Leviathon specification, but at the $400 asking price + S/H in both directions, I’m not quite ready to break out the VISA card just yet!
So, here are my considerations:
1). How important is maintaining a flat response when utilized in HT mode out to 80 Hz?
2). Am I better served by spending the difference -- $250+ -- between the two available kits on a Behringer DSP1124 to EQ the sub and listening room response as well? (as suggested at http://www.theaudioworx.com/ -- Electronic Room Treatment & Loudspeaker Correction). DSP1124 info found here:
http://www.behringer.com/02_products/prodindex.cfm?id=DSP1124P&lang=eng
3). Can I manipulate the parameters myself starting with a standard 1808 kit?
4). Should I simply continue with the good driver in hand going with the 340L/20Hz alignment as mentioned above?
And finally…
4). Is this ‘flat’ response thing just a pipe dream anyway considering room acoustics and such?
I started a MDF prototype just to get my feet wet, but before I begin to cut any hardwood stock for the final project, I’d like to wait and see what you guys have to say. For those of you playing along at home, here are the associated T/S particulars.
Thank you for your time and help. I appreciate it!
Aurasound 1808
Fs 24 Hz
Re 5.0 ohm
Qms 4.1
Qes 0.20
Vas 558 L
Xmax 18mm
Le 0.47 mH
Sd 1240 cm^2
800 W (100w)
Aurasound NRT-18 (upgraded 1808 cone kit)
Fs 25
Re 5.6 ohm
Qms 4.4
Qes 0.28
Vas 475 L
Same…
NCMS Leviathon
Fs 14 Hz
Re 5.0 ohm
Qms 11.3
Qes 0.337
Vas 579 L
Same…
Recently, I was fortunate enough to acquire a pair of Aurasound 1808 18” sub drivers; one of which is slated to upgrade the family’s HT. I used Kristian Ougaard’s UniBox 3 to model a vented system at 100 W which I found a 340 L cabinet tuned to 20 Hz seemed to be reasonable. Although the driver is rated at 800 watts and will be driven by a 700 watt/8 ohm Carver amp, I chose 100 watt nominal power as a more pragmatic value – the SOF -- )
The problem is that the Aurasound’s response is only fairly ‘flat’ in the 20 to 40 Hz range, then it continues to slowly ramp up.
20 Hz – 108.6 dB
30 Hz – 109.5 dB
40 Hz – 110.2 dB
50 Hz – 111.1 dB
60 Hz – 112.0 dB
70 Hz – 112.8 dB
80 Hz – 113.5 dB
300 Hz – 117 dB
Now, for HT that’s not all that bad of a thing, right? But for the vast majority of us, we have a one-world HT/music system. And for music, flat is where it’s at – or at least for the most part.
Here is where the North Creek Leviathon question comes into play. The second driver is in possible need of a re-cone kit, which is available from the manufacturer for $150 or so. But, if you look at the specs for the Leviathon (customized 1808), it is clear that George has done his homework. The predicted response for a vented Leviathon for a 300 L cabinet tuned to 18 Hz is spot on -- smaller cabinet, lower tuning and response as flat as a torsion box. Even better would be 340 L at 17 Hz. I can send him my driver to have it reconditioned into Leviathon specification, but at the $400 asking price + S/H in both directions, I’m not quite ready to break out the VISA card just yet!
So, here are my considerations:
1). How important is maintaining a flat response when utilized in HT mode out to 80 Hz?
2). Am I better served by spending the difference -- $250+ -- between the two available kits on a Behringer DSP1124 to EQ the sub and listening room response as well? (as suggested at http://www.theaudioworx.com/ -- Electronic Room Treatment & Loudspeaker Correction). DSP1124 info found here:
http://www.behringer.com/02_products/prodindex.cfm?id=DSP1124P&lang=eng
3). Can I manipulate the parameters myself starting with a standard 1808 kit?
4). Should I simply continue with the good driver in hand going with the 340L/20Hz alignment as mentioned above?
And finally…
4). Is this ‘flat’ response thing just a pipe dream anyway considering room acoustics and such?
I started a MDF prototype just to get my feet wet, but before I begin to cut any hardwood stock for the final project, I’d like to wait and see what you guys have to say. For those of you playing along at home, here are the associated T/S particulars.
Thank you for your time and help. I appreciate it!
Aurasound 1808
Fs 24 Hz
Re 5.0 ohm
Qms 4.1
Qes 0.20
Vas 558 L
Xmax 18mm
Le 0.47 mH
Sd 1240 cm^2
800 W (100w)
Aurasound NRT-18 (upgraded 1808 cone kit)
Fs 25
Re 5.6 ohm
Qms 4.4
Qes 0.28
Vas 475 L
Same…
NCMS Leviathon
Fs 14 Hz
Re 5.0 ohm
Qms 11.3
Qes 0.337
Vas 579 L
Same…
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