Today's Deal of the Day at PE:
http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=295-085&dotd=122004
I know, I know, they are PA drivers, but they look like they would do at least a decent job as subs if one could live with with the big Vas.
Fs=25 Hz, Vas=16.12 ft3, Qts=0.34, Xmax=6mm, Le=2mH
Did I miss something to consider?
http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=295-085&dotd=122004
I know, I know, they are PA drivers, but they look like they would do at least a decent job as subs if one could live with with the big Vas.
Fs=25 Hz, Vas=16.12 ft3, Qts=0.34, Xmax=6mm, Le=2mH
Did I miss something to consider?
One of the dayton DVCs might have more VD. Id look into those, besides with a fs of 25, its going to be a bit difficult making it reach low enough for HT.
True, the DVC has more Sd for the same price, but with more than twice as much excursion to do the job, not good for distortion. And plenty of people are implementing subs with a higher Fs than 25 Hz, albeit using active EQ.
I was trying to do a involved simulation, something that looks hard at Le's effect on the response, 2 VC's in parallel etc, something I've never really done before. I just played with Winisd Pro enough to see that it doesn't use Le, at least I could not get it to change the response curve or box calc by just changing the value of Le. Any sim guru's reading this?
I was trying to do a involved simulation, something that looks hard at Le's effect on the response, 2 VC's in parallel etc, something I've never really done before. I just played with Winisd Pro enough to see that it doesn't use Le, at least I could not get it to change the response curve or box calc by just changing the value of Le. Any sim guru's reading this?
If you want to change the Le parameter in WinISD Pro, you need to change it, save the driver parameters, and load it in a new project.
That is not true, WinISD Pro uses Le.
If I change Le, the high frequency response of the driver changes dramatically.
You didn't follow my insctructions or you are not using the lastest version.
You must change Le, save parameters, open a new project, reload the driver and see the changes.
If I change Le, the high frequency response of the driver changes dramatically.
You didn't follow my insctructions or you are not using the lastest version.
You must change Le, save parameters, open a new project, reload the driver and see the changes.
That sub should have about the same VD as the Shiva. It actually looks like a good buy.
In a big box it gets a very similar response and max SPL to the Shiva with 350w, while the 18 needs only about 100w.
You can get an F3 of about 30 Hz quite easily and exceed THX requirements.
In a 250L box it can match the output of the Shiva above about 23 Hz when tuned to 25 Hz. 109 dB @ 25 Hz
If you don't mind big and ugly, then it's a bang for buck way to get low distortion, not only due to the low cost of the driver, but also low amplifier cost. Very easy to power.
From a performance and linearity point of view, it's probably a good idea to have a large SD and low xmax rather than a small SD and large xmax. It's also a good idea from a budget point of view. Trying to get low distortion with small subs is expensive!
20 Hz anechoic extension is not needed. Room gain can easily extend useable output, and many rooms don't handle 20 Hz that well anyway (rattles, etc). Also, most of the fun bass in movies is around the midbass anyway.
In a big box it gets a very similar response and max SPL to the Shiva with 350w, while the 18 needs only about 100w.
You can get an F3 of about 30 Hz quite easily and exceed THX requirements.
In a 250L box it can match the output of the Shiva above about 23 Hz when tuned to 25 Hz. 109 dB @ 25 Hz
If you don't mind big and ugly, then it's a bang for buck way to get low distortion, not only due to the low cost of the driver, but also low amplifier cost. Very easy to power.
From a performance and linearity point of view, it's probably a good idea to have a large SD and low xmax rather than a small SD and large xmax. It's also a good idea from a budget point of view. Trying to get low distortion with small subs is expensive!
20 Hz anechoic extension is not needed. Room gain can easily extend useable output, and many rooms don't handle 20 Hz that well anyway (rattles, etc). Also, most of the fun bass in movies is around the midbass anyway.
Most of the fun bass in movies is Infrasonic IMO😀. And making a room more rattle proof isnt hard, just buy loooottssss of felt stick ons(like to protect hardwood floors from furniture markings.
It can be a bit more involved than that!
I have two high excursion 12" subs and when they are idling at about 8mm excursion at 20 Hz, the whole room rattles - windows, pictures on the wall, the door, objects in the room. As it's not my room I have a real problem. I hate to think what it would sound like if I actually had the subs working hard! (ie used the remaining 38mm of excursion!)
Even down as low as 20 Hz, the bass needs to be louder than you think to make an impact. A lot of speakers even struggle to reach the level where 20 Hz is even just audible. Some such speakers are often but probably incorrectly called subwoofers!
In order to get bass below 20 Hz, you give up the midbass which has a lot more punch and impact. Not worth it IMO unless you have a big budget.
Movies with a lot of bass tend to have a lot of energy around 40 - 60 Hz IMO. Even where there is a lot of bass down to 10 Hz, the main impact will come from the midbass. I heard recently a PA sub which goes down to 50 Hz. It was clearly lacking that sense of power that you get with strong outpu down to 40 Hz. However, below this point you start to get diminishing returns as you go deeper.
That said, it's quiet easy to get down to 20 hz with room gain. Below that you not only need 4x the displacement / octave, you also are working against the diminishing impact lower frequencies have as they are harder to perceive. A local speaker builder once told me about building massive subs for a wealthy guy who didn't know too much about audio - he wanted subsonic extension and he got it but didn't like it. The windows and everthing in the room was shaking like crazy and he said "where's the bass?" He ended up changing the subs - making them smaller and tuned higher to get more midbass, then he was happy.
I have two high excursion 12" subs and when they are idling at about 8mm excursion at 20 Hz, the whole room rattles - windows, pictures on the wall, the door, objects in the room. As it's not my room I have a real problem. I hate to think what it would sound like if I actually had the subs working hard! (ie used the remaining 38mm of excursion!)
Even down as low as 20 Hz, the bass needs to be louder than you think to make an impact. A lot of speakers even struggle to reach the level where 20 Hz is even just audible. Some such speakers are often but probably incorrectly called subwoofers!
In order to get bass below 20 Hz, you give up the midbass which has a lot more punch and impact. Not worth it IMO unless you have a big budget.
Movies with a lot of bass tend to have a lot of energy around 40 - 60 Hz IMO. Even where there is a lot of bass down to 10 Hz, the main impact will come from the midbass. I heard recently a PA sub which goes down to 50 Hz. It was clearly lacking that sense of power that you get with strong outpu down to 40 Hz. However, below this point you start to get diminishing returns as you go deeper.
That said, it's quiet easy to get down to 20 hz with room gain. Below that you not only need 4x the displacement / octave, you also are working against the diminishing impact lower frequencies have as they are harder to perceive. A local speaker builder once told me about building massive subs for a wealthy guy who didn't know too much about audio - he wanted subsonic extension and he got it but didn't like it. The windows and everthing in the room was shaking like crazy and he said "where's the bass?" He ended up changing the subs - making them smaller and tuned higher to get more midbass, then he was happy.
Tempest in a 250l enclosure tuend to 19hz should have strong output at 16 hz and still have up to 50 or 60 hz. I would cross my mains at 60ish anyway so this is not a problem. And just cause most movies have lots of midbass, that doesnt mean its more fun than some LOW LOW bass
Pictures rattling are EASILY fixed with electrical tape between the frame and glass, and felt stick ons between frame and wall. Weather stripping REALLY helps with doors.
Pictures rattling are EASILY fixed with electrical tape between the frame and glass, and felt stick ons between frame and wall. Weather stripping REALLY helps with doors.
Yes but how much output at 16 Hz?
I'll be lucky if I can get away with doing all I'd need to do to revmove all rattles in the room (and the adjacent rooms)
I'll be lucky if I can get away with doing all I'd need to do to revmove all rattles in the room (and the adjacent rooms)
in a 12x9 room with 240 watts on tap? im not exactly sure how much output, but DEFINATELY enough to feel it 😀. Ah well to each his own i guess. i watch mostly movies, and think that infrasonic output is important.
By the way, i wish i had your AV12s
By the way, i wish i had your AV12s
At 16 Hz, the output is around -8 dB from the 72 Hz reference where output is the highest anechoic.
A big box like that, I would tune it lower. The rolloff is constant to about 12 Hz tuning, under that you have a small peak at the tuning frequency. With a 12 Hz tuning, rolloff is constant up to 10 Hz before dropping sharply. Might match very well with the room gain so it could be flat down to that point.
A big box like that, I would tune it lower. The rolloff is constant to about 12 Hz tuning, under that you have a small peak at the tuning frequency. With a 12 Hz tuning, rolloff is constant up to 10 Hz before dropping sharply. Might match very well with the room gain so it could be flat down to that point.
Ahh... But in larger enclosures, you start to really get down into the freq zone... But there the danger lies...
A friend, who I set up with a 300+ litre sonotube, doesn't understand that he can't try to hit 120db with it...
And I'm looking at SIX of the PE Quatro 15" drivers right now...
I'm really glad I'm not my neighbors...
A friend, who I set up with a 300+ litre sonotube, doesn't understand that he can't try to hit 120db with it...
And I'm looking at SIX of the PE Quatro 15" drivers right now...
I'm really glad I'm not my neighbors...
If you want to hit 120 dB, it's easy, just get a driver with high efficiency, but you lose the low end. Also, who need 120 dB? That's another debate 😉
6 Quadro 15", interesting project!
6 Quadro 15", interesting project!
WHY SIX?! thats almost 10 litres of linear displacement. thats a bit much IMO. unless youre doing IB that would be amazing.
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