Hi everyone,
Great forum massive amount of info!
Ok, what frequency are you guys tuning ported enclosures around for best SQ?
Or better still your opinion on tuning frequency for the following:
I have a DD9112 sitting on my shelf beckoning the HT room. It's music handling is 1600wrms(underrated) and I will be feeding it 2000wrms.
It will be running along side Aaron SW-240 (dual 10's) & Aaron ATS-5's (dual 8" towers).
An EQ for proper component matching is coming later.
thanks in advance for your help
Great forum massive amount of info!
Ok, what frequency are you guys tuning ported enclosures around for best SQ?
Or better still your opinion on tuning frequency for the following:
I have a DD9112 sitting on my shelf beckoning the HT room. It's music handling is 1600wrms(underrated) and I will be feeding it 2000wrms.
It will be running along side Aaron SW-240 (dual 10's) & Aaron ATS-5's (dual 8" towers).
An EQ for proper component matching is coming later.
thanks in advance for your help
I think you have the first and second ones the wrong way round. The point of burp testing is that it gets you the max you can out of the system, and this is not sustainable.
Anyway, a quick check indicates that because Vas is low you will struggle to accomodate the vent in the box due to it requiring large diameter and long length. Qts is a little on the high side for a vented box as well.
Is there a particular reason you want vented? Have you modelled a sealed box to see if it can give you the SPL you want?
Anyway, a quick check indicates that because Vas is low you will struggle to accomodate the vent in the box due to it requiring large diameter and long length. Qts is a little on the high side for a vented box as well.
Is there a particular reason you want vented? Have you modelled a sealed box to see if it can give you the SPL you want?
Greets!
Ideally you want the tuning to be well down into the room's pressure mode BW, so if you have a large and/or leaky room you need to go with a ~critically damped IB alignment (0.5 Qtc) IMO.
That said, my room doesn't measure any real gain and calcs not starting until somewhere around 6 Hz, but a 'stereo' corner loaded 16 Hz EBS alignment works well to get good SQ with a bit more gain in the audible BW. Note that an EBS tuned below ~(0.707*Fs) isn't a good plan IMO so I recommend a very low Fs driver and use as many as required to get the desired mechanical power handling, so unless your HT room is closet sized, probably best to stick it in an IB and use digital EQ to shape its in-room response.
FWIW, four 20.0Hz Fs HE 15" work well enough for me. When I escalated up to dual corner loased Servo-Drive Contrabasses to get a flatter in-room response to a lower cut-off, they shook my stick built/floating floor house to pieces pounding out special effects and low organ notes up to ~live levels in some cases, destroying most of the drywall joints in every room and cracking one of the foundation pillars under the listening room and still dealing with the consequences years later, so something to consider when determining a peak SPL/BW.
GM
Ideally you want the tuning to be well down into the room's pressure mode BW, so if you have a large and/or leaky room you need to go with a ~critically damped IB alignment (0.5 Qtc) IMO.
That said, my room doesn't measure any real gain and calcs not starting until somewhere around 6 Hz, but a 'stereo' corner loaded 16 Hz EBS alignment works well to get good SQ with a bit more gain in the audible BW. Note that an EBS tuned below ~(0.707*Fs) isn't a good plan IMO so I recommend a very low Fs driver and use as many as required to get the desired mechanical power handling, so unless your HT room is closet sized, probably best to stick it in an IB and use digital EQ to shape its in-room response.
FWIW, four 20.0Hz Fs HE 15" work well enough for me. When I escalated up to dual corner loased Servo-Drive Contrabasses to get a flatter in-room response to a lower cut-off, they shook my stick built/floating floor house to pieces pounding out special effects and low organ notes up to ~live levels in some cases, destroying most of the drywall joints in every room and cracking one of the foundation pillars under the listening room and still dealing with the consequences years later, so something to consider when determining a peak SPL/BW.
GM
Breaking your house with HT 
Classic, I love it!!
My room is 4x3m(13'x10') and enclosed, dedicated HT room.
The encl. does not have to be ported if you believe sealed will yeild better results.
The port does not have to be internal. I would make a feature out of it externally.
Also this sub is all I have available to me for a while. If I spend any more on the HT the missus will shoot me.
100L @ 18hz so far, anyone want to second that or beg to differ?
Classic, I love it!!My room is 4x3m(13'x10') and enclosed, dedicated HT room.
The encl. does not have to be ported if you believe sealed will yeild better results.
The port does not have to be internal. I would make a feature out of it externally.
Also this sub is all I have available to me for a while. If I spend any more on the HT the missus will shoot me.
100L @ 18hz so far, anyone want to second that or beg to differ?
Making the Box a bit larger would allow a shorter vent for the same tuning frequency....
My suggestion:
Build a few ports into or out of the box with panels(if they're slot type ports) or plugs(for round ports) to close them off. You could try tunings at 18 24 and 30hz and also have a plug/panel to close off all the ports for sealed box operation. One box that can be 4 different enclosures sure beats building 4 different enclosures
My suggestion:
Build a few ports into or out of the box with panels(if they're slot type ports) or plugs(for round ports) to close them off. You could try tunings at 18 24 and 30hz and also have a plug/panel to close off all the ports for sealed box operation. One box that can be 4 different enclosures sure beats building 4 different enclosures
Greets!
OK, so in theory room gain begins at ~565/13 = ~43.46 Hz, so between this and my experience, a vented 18 Hz Fb is ill advised. Apparently you want a low tuned vented sub no matter what, so if you build a typical cube or rectangular cab, then based on published specs and ~3.83 ft^3 it will need a minimum 46"^2 vent area 65" long to ensure a low vent mach/2 kW and will have to be stuffed to a fare-thee-well since it's so underdamped.
To increase damping/reduce vent length a bit, a ML-TL is much preferred IMO, though more effort to make, so I recommend a ~84.15" pathlength/~78.645"^2 cross sectional area (CSA) folded pipe terminating into a 46"^2 vent 55" long with the driver down ~26.55" from the closed end. Loosely stuff the pipe as required. FWIW, 0.2 lbs/ft^3 sims fine when an 80 Hz XO is factored in.
GM
OK, so in theory room gain begins at ~565/13 = ~43.46 Hz, so between this and my experience, a vented 18 Hz Fb is ill advised. Apparently you want a low tuned vented sub no matter what, so if you build a typical cube or rectangular cab, then based on published specs and ~3.83 ft^3 it will need a minimum 46"^2 vent area 65" long to ensure a low vent mach/2 kW and will have to be stuffed to a fare-thee-well since it's so underdamped.
To increase damping/reduce vent length a bit, a ML-TL is much preferred IMO, though more effort to make, so I recommend a ~84.15" pathlength/~78.645"^2 cross sectional area (CSA) folded pipe terminating into a 46"^2 vent 55" long with the driver down ~26.55" from the closed end. Loosely stuff the pipe as required. FWIW, 0.2 lbs/ft^3 sims fine when an 80 Hz XO is factored in.
GM
GM said:
GM this is not so
I did state in an earlier post that I would go sealed if you believe it will yeild better results.Obviously you are quite knowledgeable and I respect your knowledge.
What I'm saying here is; I want more bottom end bass as the dual 10's don't go low & loud.
The only amp I have is the Gem Sound PA-5505 and the only subs I have areDD9112 & DD9512f
I cannot buy anything else at all, she will shoot me....repeatedly.
So I have to work with these components. If it is going to sound like crap please tell me so but if there is an enclosure I can build that will sound good please let me know.
I am capable of building complex enclosures. I have a workshop and the tools *no CNC router though*
So please fire away with any enclosure type you believe will produce good results, if it is possible with these subs.
Greets!
OK, I was in a hurry this morning and didn't 'see' that the 100L/18 Hz design listed in your post was actually Simon's suggestion. My bad. Still, I thought I made it plain that IMO tuning this far below Fs isn't a good plan and that sealed best suited your stated performance requirements.
Unless you have a very 'leaky' room for whatever reason, I still think a digitally EQ'd low Q sealed cab is the way to go, but the well damped ML-TL I suggested looks good in a sim too and if you take a pic of its folded, stepped labyrinth construction, will make for an audio conversation piece. If it has too much gain and/or not enough SQ in-room, then you can either digitally EQ it down or 'stick a sock in it' so to speak to further damp/attenuate it, or just block the vent for a ~IB response.
For sure I do not recommend a typical sub box design though as you will be hard pressed to stuff it enough to damp it down for good SQ due to it being tuned so far below Fs in such an acoustically large Vb (for the driver's compliance).
Trust me, in-room even the sealed alignment will drown out the 10's down low and the ML-TL sims ~87 dB/16 Hz half space sensitive, so with 2 kW on tap your wife may have even better reasons for using you for target practice.
All this assumes of course that the published specs are reasonably accurate and I'm not familiar with this brand, so as always YMMV.
GM
OK, I was in a hurry this morning and didn't 'see' that the 100L/18 Hz design listed in your post was actually Simon's suggestion. My bad. Still, I thought I made it plain that IMO tuning this far below Fs isn't a good plan and that sealed best suited your stated performance requirements.
Unless you have a very 'leaky' room for whatever reason, I still think a digitally EQ'd low Q sealed cab is the way to go, but the well damped ML-TL I suggested looks good in a sim too and if you take a pic of its folded, stepped labyrinth construction, will make for an audio conversation piece. If it has too much gain and/or not enough SQ in-room, then you can either digitally EQ it down or 'stick a sock in it' so to speak to further damp/attenuate it, or just block the vent for a ~IB response.
For sure I do not recommend a typical sub box design though as you will be hard pressed to stuff it enough to damp it down for good SQ due to it being tuned so far below Fs in such an acoustically large Vb (for the driver's compliance).
Trust me, in-room even the sealed alignment will drown out the 10's down low and the ML-TL sims ~87 dB/16 Hz half space sensitive, so with 2 kW on tap your wife may have even better reasons for using you for target practice.
All this assumes of course that the published specs are reasonably accurate and I'm not familiar with this brand, so as always YMMV.
GM
Don't write off the vented box yet. Whilst it's generally true that tuning or even driving a drive unit below Fs is not a good thing due to moving into the suspension compliance region, with todays high quality drivers with linear suspensions this is not so much of a problem. Indeed, if somebody will recommend EQ below Fs to get low down output, then by the same token you can also vent below Fs.
kyaloz said:Breaking your house with HT
My room is 4x3m(13'x10') and enclosed, dedicated HT room.
The encl. does not have to be ported if you believe sealed will yeild better results.
The port does not have to be internal. I would make a feature out of it externally.
Also this sub is all I have available to me for a while. If I spend any more on the HT the missus will shoot me.
100L @ 18hz so far, anyone want to second that or beg to differ?
Its small room for deep bass.
For BR I calculate 46 L and Fb=29 Hz. Port diametar 85 mm, 360 mm long. You can go with closed box of 30-31 L (full dampened Fc is around 43 Hz).
Anyway, its best to go with active. You dont have to think about efficient to match with the rest, and you can try different cut off frequncies.
Do not try to built something you dont understand.
Dont let us to persuade you for any design. Make closed box.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.