I am much interested on the "peerless - bass shy" thread below. Glad that the CSX 10" woofer gets attention.
I would like to try the CSX 10" in sealed enclosures in stereo bass modules to accompany my fulll range drivers with XO aro 140 Hz.
I have questions to the experts here - glad fore any replies. I am just a beginner myself but I got myself powerful software LspCAD which I now play around with.
(1)
Why is so many people looking for "flat responce down to 30-40Hz ??
In any given room this will always result in a boomy bass due to room gain wouldn't it?
When experimenting CSX 10" with LspCAD with room gain, I can get a fairly "flat" response to 30Hz in a SEALED cabinette. With BR I will on the other hand get "boom" aro 30-60Hz. The size of the boom depends on size of the room of course but for most room sizes the boom is there - in case BR.
(2)
In case of Sealed, there is quite big difference in the dB between 20-40 Hz depending on Cabinette volume:
Qtc = 0.5 good bass extension down to 30Hz
Qtc = 0.707 less good
I am writing this not from my home so I do not have LspCAD in front of me now. (Do not remember all numbers) but what I want to say is that without room gain there is very small differenses in frequency responce for different Box sealed volumes. However, once you consider room gain it makes huge differences especially in the range 20-40Hz.
My 2:nd question then are:
In the case sealed CSX 10" - the bigger volume always simulates better (best is infinite box volume). Are then no disadvantage of big box ?? How about transient response and so on? Shall I try keep Volume down for some reason ?
Peerless recommends 50L sealed box. Is it to limit cone excursion ?
LageB
I would like to try the CSX 10" in sealed enclosures in stereo bass modules to accompany my fulll range drivers with XO aro 140 Hz.
I have questions to the experts here - glad fore any replies. I am just a beginner myself but I got myself powerful software LspCAD which I now play around with.
(1)
Why is so many people looking for "flat responce down to 30-40Hz ??
In any given room this will always result in a boomy bass due to room gain wouldn't it?
When experimenting CSX 10" with LspCAD with room gain, I can get a fairly "flat" response to 30Hz in a SEALED cabinette. With BR I will on the other hand get "boom" aro 30-60Hz. The size of the boom depends on size of the room of course but for most room sizes the boom is there - in case BR.
(2)
In case of Sealed, there is quite big difference in the dB between 20-40 Hz depending on Cabinette volume:
Qtc = 0.5 good bass extension down to 30Hz
Qtc = 0.707 less good
I am writing this not from my home so I do not have LspCAD in front of me now. (Do not remember all numbers) but what I want to say is that without room gain there is very small differenses in frequency responce for different Box sealed volumes. However, once you consider room gain it makes huge differences especially in the range 20-40Hz.
My 2:nd question then are:
In the case sealed CSX 10" - the bigger volume always simulates better (best is infinite box volume). Are then no disadvantage of big box ?? How about transient response and so on? Shall I try keep Volume down for some reason ?
Peerless recommends 50L sealed box. Is it to limit cone excursion ?
LageB
Up until last nite I was running CSX10s for bass. I had them in sealed .7Q enclosures and they had good in-room output to 30Hz. A pretty good driver for the money, IMO.
I agree with you on the sealed enclosure/room gain comments. I wind up with ~flat in-room response with all the sealed enclosures I've tried. Why build vented and then have to EQ down to achieve a good response?
As for box size and tuning.....Too large an enclosure will have the driver rolling off too early and can be considered dry sounding. Too small an enclosure and you wind up with a hump in the FR before the FR starts to roll off. Transient response/Group delay also suffers.
In my room, a Qtc of ~.6 seems to blend well with my room gain and yields ~flat response/nice smooth rolloff.
Pete
I agree with you on the sealed enclosure/room gain comments. I wind up with ~flat in-room response with all the sealed enclosures I've tried. Why build vented and then have to EQ down to achieve a good response?
As for box size and tuning.....Too large an enclosure will have the driver rolling off too early and can be considered dry sounding. Too small an enclosure and you wind up with a hump in the FR before the FR starts to roll off. Transient response/Group delay also suffers.
In my room, a Qtc of ~.6 seems to blend well with my room gain and yields ~flat response/nice smooth rolloff.
Pete
I have just finished building a sealed Sub using the Peerless CSX 10" (850146 I think) in a 46l box.
Before I built it I played around with various software and looked at lots of graphs, which mostly meant nothing to me... ;-)
Anyway - I heard someone who did a similar thing with the peerless 8" and thought, enough messing around, I'll just do it.
And the important thing - it sounds great.
With a 100W amp it is way more powerful than I need for the room it is in. Nice and controlled with stereo music, and possibly over the top with DVD movies (still got some tuning to do).
Not quite the small box I thought I could hide behind the sofa though - at 20kg and the size of a small coffe table. Oh well.
James
Before I built it I played around with various software and looked at lots of graphs, which mostly meant nothing to me... ;-)
Anyway - I heard someone who did a similar thing with the peerless 8" and thought, enough messing around, I'll just do it.
And the important thing - it sounds great.
With a 100W amp it is way more powerful than I need for the room it is in. Nice and controlled with stereo music, and possibly over the top with DVD movies (still got some tuning to do).
Not quite the small box I thought I could hide behind the sofa though - at 20kg and the size of a small coffe table. Oh well.
James
Seems I can not go wrong wíth CSX 10" in sealed boxes...
Big size of box is not a problem in my case. If I choose 50L I know I will be safe, because many people seems adopt that size and it is also what peerless is recommending.
Question ??
------------
But what happen if I build a very big Box - say 100L ??
What are the drawbacks ?
If I select a box of 100L I get much improved LF extension in my room simulations. The issue that the driver would be rolling off too early is not a problem because it is really very minor deviations - compared to room gain.
LageB
Big size of box is not a problem in my case. If I choose 50L I know I will be safe, because many people seems adopt that size and it is also what peerless is recommending.
Question ??
------------
But what happen if I build a very big Box - say 100L ??
What are the drawbacks ?
If I select a box of 100L I get much improved LF extension in my room simulations. The issue that the driver would be rolling off too early is not a problem because it is really very minor deviations - compared to room gain.
LageB
Mos,
I made sim as follows, as example:
(1)
QB3/SQB3 Alignment, 80L Box, Port length 56cm
(2)
Without room gain I have (as reference 96dB flat with -3dB at 30Hz
(3)
With room gain 3.5x5meter room
100Hz 96dB
90Hz 97dB
80Hz 98dB
70Hz 98dB
60Hz 101dB
50Hz 105dB
40Hz 108Hz
30Hz 109Hz
20Hz 104Hz
LageB
I made sim as follows, as example:
(1)
QB3/SQB3 Alignment, 80L Box, Port length 56cm
(2)
Without room gain I have (as reference 96dB flat with -3dB at 30Hz
(3)
With room gain 3.5x5meter room
100Hz 96dB
90Hz 97dB
80Hz 98dB
70Hz 98dB
60Hz 101dB
50Hz 105dB
40Hz 108Hz
30Hz 109Hz
20Hz 104Hz
LageB
Hi
I've been re-reading this thread and I've got some additional thoughts on the whole sealed box + room gain = flat versus ported box + room gain = bass hump thing.
Take a typical case where you have a good 10" like the Peerless 850146 down near the floor.
Now, due to baffle step loss (which would be most pronounced at these lower freqs), if you add in say 3-6db of room gain, effectively you're just restoring the driver to it's nominal sensitivity. True?
Therefore, surely whichever way you go, sealed or ported the baffle step/room gain factors simply cancel each other out.
Any thoughts?
Mos
I've been re-reading this thread and I've got some additional thoughts on the whole sealed box + room gain = flat versus ported box + room gain = bass hump thing.
Take a typical case where you have a good 10" like the Peerless 850146 down near the floor.
Now, due to baffle step loss (which would be most pronounced at these lower freqs), if you add in say 3-6db of room gain, effectively you're just restoring the driver to it's nominal sensitivity. True?
Therefore, surely whichever way you go, sealed or ported the baffle step/room gain factors simply cancel each other out.
Any thoughts?
Mos
Transmission Line. You are looking for a clean, "boxless" sound that I think the transmission line can supply for you. The distinction is that there are some transmission lines that can waffle the legs on your pants from the listening position. Perhaps you could do something similar with these woofers?
http://www.t-linespeakers.org/projects/nick/aqa.html
Make a couple of these AQA lines downfiring. Or, if you want a single box that can do the stereo bass, check into the Fried "coffin" subwoofer. http://www.t-linespeakers.org/classics/coffin/index.html
This is, of course, only if the woofers have a Qts between 0.3 and 0.5. Now you have bass power, and you can EQ suitably for the room transfer function. Then your woofers aren't as excursion limited at the lower frequencies (this is, at least, my understanding). The only limitation is size.
http://www.t-linespeakers.org/projects/nick/aqa.html
Make a couple of these AQA lines downfiring. Or, if you want a single box that can do the stereo bass, check into the Fried "coffin" subwoofer. http://www.t-linespeakers.org/classics/coffin/index.html
This is, of course, only if the woofers have a Qts between 0.3 and 0.5. Now you have bass power, and you can EQ suitably for the room transfer function. Then your woofers aren't as excursion limited at the lower frequencies (this is, at least, my understanding). The only limitation is size.
>Why build vented and then have to EQ down to achieve a good response?
====
If you measure your room and find the right driver/alignment to mirror it, then the only reason would be to gain system efficiency/lower distortion, which is enough for me to justify doing it, but I've measured very few rooms that had enough gain to flatten a sealed system unless Fb was quite low, especially with a low Qtc alignment.
WRT HT apps, DD (and I assume DTS) reference specs a flat amplitude response, so you want a rising LF response with decreasing frequency. For sure, a small room or an apt/condo dweller is better off with sealed if it can get down to ~40Hz.
====
>But what happen if I build a very big Box - say 100L ??
What are the drawbacks ?
====
Lower power handling, so the room has to make up the difference, and if overdamped (Qtc <0.5), then a sense of 'speed' at the expense of good tonal balance/transient response.
You don't say what gain value you used, but if you used the 6dB default, then for it to be ~accurate means your room is extremely well built and very 'live' (reflective). 3-4dB is more realistic unless it's a (mostly) underground basement.
====
>Take a typical case where you have a good 10" like the Peerless 850146 down near the floor.
>Now, due to baffle step loss (which would be most pronounced at these lower freqs), if you add in say 3-6db of room gain, effectively you're just restoring the driver to it's nominal sensitivity. True?
====
If it's close enough to the floor to mirror image, IOW create a virtual second driver, there's no baffle step loss, so any room gain is just that.
GM
====
If you measure your room and find the right driver/alignment to mirror it, then the only reason would be to gain system efficiency/lower distortion, which is enough for me to justify doing it, but I've measured very few rooms that had enough gain to flatten a sealed system unless Fb was quite low, especially with a low Qtc alignment.
WRT HT apps, DD (and I assume DTS) reference specs a flat amplitude response, so you want a rising LF response with decreasing frequency. For sure, a small room or an apt/condo dweller is better off with sealed if it can get down to ~40Hz.
====
>But what happen if I build a very big Box - say 100L ??
What are the drawbacks ?
====
Lower power handling, so the room has to make up the difference, and if overdamped (Qtc <0.5), then a sense of 'speed' at the expense of good tonal balance/transient response.
You don't say what gain value you used, but if you used the 6dB default, then for it to be ~accurate means your room is extremely well built and very 'live' (reflective). 3-4dB is more realistic unless it's a (mostly) underground basement.
====
>Take a typical case where you have a good 10" like the Peerless 850146 down near the floor.
>Now, due to baffle step loss (which would be most pronounced at these lower freqs), if you add in say 3-6db of room gain, effectively you're just restoring the driver to it's nominal sensitivity. True?
====
If it's close enough to the floor to mirror image, IOW create a virtual second driver, there's no baffle step loss, so any room gain is just that.
GM
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