Alpine Type R SWR1021 dual Subs

[VolvoHeretic]

Total Noob here, but I want to go for it….
Okay, Here is my build thread for two Alpine type R SWR 1020 Subs, but the only info I can find is for the 1021's, but so be it... I have found two net 1.5 cu. ft. boxes to use and come up with a Base Reflex port; 2"x10"x vent length of 53.5”. Is an abrupt folded vent bad? I have designed a 2” inside radius folded vent that I could easily build if it helps.
Pictures to come shortly….

Anyway, My friend came over to hear the Altec guitar 417-8hII/ 806/ B32 + Alpines in .75 cu. Ft. sealed boxes controlled with a mere graphic EQ boosting the lowest and cutting the higher frequencies.

After complaining for a wile, he admitted that the combo did sound great.


I said that I was going to buy a $100 electronic XO and he replied; “I am
an electrical engineer “GENIOUS”” and that he could build me a low pass filter. I hope that I am not waiting till Hell freezes over. LOL

Anyone have the world’s best circuit design for an 80Hz 24db low pas active filter, I have found a couple on line?


Off hand I can’t find the links I copied off of another computer, but it want’s to know the pre out and amp in impendence.
Thanks in advance for any help. And be gentile, I am willing to learn soldering, PCB printing and producing and think this will be fun.

 

[Inductor]

I presume it's for home use...

 

[Inductor]

Alpine SWR-10D2 10" Subwoofer (2Ω + 2Ω)
http://support.alpine-usa.com/products/documents/OM_SWR-10D2_4_12D2_4.pdf

I don't know but there's something fishy. 😱
How do you plan to make a vent 53.5”/1.35 meters long ?!

two net 1.5 cu. ft. boxes to use and come up with a Base Reflex port; 2"x10"x vent length of 53.5”

The box is also to big (but that's not the main problem). An aceptable enclosure size (each driver) as per spec.sheet is 1.3ft³ = 36L not 1.5ft³ = 42.5L. That's enough for 2 drivers almost...
What amp are you planning to use? This woofer requires many thousands W for max. excursion/output i.e. >1000W RMS. If it was for a car I would say drop it in sealed enclosure and you would need only 300/500W power (less LF extension in home, because of the car-gain). 😎

 

[VolvoHeretic]

This is for home use and they are 4+4 ohms @ 300 watts rms both coils driven. I am using a Crown DC300A rated at 150 watts rms at 8 ohms. I tried running them in .75 cu ft sealed boxes with one coil hooked up @ 4 ohms which would be 300 watts from amp into 150 watts max for the one coil at the speaker. I found out that I would have to change the data for WinISD to get decent results, but haven't figured out what to change yet.

I was going to create a folded vent out the back of the box and vent it out the bottom front. It seems to me that square corners must impede air flow so I was going to bend sheet metal around a curved form with 2" inside radiuses and line it with rubber conveyor belting. 🙂 I have an illustration that I can upload tonight.

 

[Inductor]

This is for home use and they are 4+4 ohms

You mean your sub is 4+4. Explain what (4) stands for, it's for coil or for driver.
There's another driver SWR-10D4, but I'm confused about the description and specs of your sub. If none of this drivers, can you publish them or post a link?!
Alpine SWR-10D4 10" Subwoofer (4Ω + 4Ω)

I don't know but there's something fishy. 😱
How do you plan to make a vent 53.5”/1.35 meters long ?!

Please note,
Refer to proportions and other design related with ports, here by another member (I know it's for a different driver/enclosure) because your dimensions for the port are not a standard procedure if you understand me. In such cases design can be achieved with 1 or 2 passive drivers.
http://www.diyaudio.com/forums/subw...vented-enclosures-18tbx100-3.html#post3566372

 

[VolvoHeretic]

Sorry, I ment SWR-1040D. It is 4ohm + 4ohm. Here is a link for the SWR-1041D data pdf:
http://vault.alpine-usa.com/products/documents/OM_SWR-1241D.PDF

If 1.5 cu ft is too big, I can incorperate .2 cu ft of the duct inside the box.

I am thinking that I would use 3/4" board to reinforce the straight sections and belting for the curved ones. I have also figured it with cut sections of 2" and 4" PVC pipe.

 

[j.michael droke]

Alpine SWR?

Sorry, I ment SWR-1040D. It is 4ohm + 4ohm. Here is a link for the SWR-1041D data pdf:


http://vault.alpine-usa.com/products/documents/OM_SWR-1241D.PDF

If 1.5 cu ft is too big, I can incorperate .2 cu ft of the duct inside the box.
I am thinking that I would use 3/4" board to reinforce the straight sections and belting for the curved ones. I have also figured it with cut sections of 2" and 4" PVC pipe.

Hi there VH: If your speaker (driver) is 10-inches, then do not use T/S parameters for Alpine SWR 1241D (your reference above)! 1241D is a 12-inch diameter driver.

The current Alpine designations were correctly referenced by "inductor" above 10D4, meaning 10=inch diameter, D dual voice coils and 4=ohm impedance for both coils (4x4). The T/S parameters for the previous Alpine's AWR 1041D are different from the current ones: (from Alpine web support)

10D4/ 1041D// 1041D(your driver?)
Re= 3.8/ 3.6 ohms each
Ind= 3.04/ 3.92 mh
Fs= 32/ 30 hz
Vas= 18 / 29L
Qms= 7.05/ 8.70
Qes= 0.59/ 0.43
Qts= 0.55/ 0.41
Sd= 333./ 320.47 cm^2
Xmax= 20./ 13.9mm

The upshot of this is your calculations may not be based on the proper T/S parameters. Your calculated port length of 53-inches may not give acceptable results. The best solution is to obtain the T/S by testing the driver with a woofer tester such as WT-3 from Parts Express. ...regards, Michael

 

[VolvoHeretic]

The Alpine PDF site includes all of the drivers including the 1041D. Yes I realize the T/S specs are probably different than the 1040D as is also the 1042D. I have been fooling around with WinISD, but I wouldn't trust anything it says (garbage in - garbage out). It did however say that the optimum box size was right around 1.3 cu ft with (2) 4" dia. port lengths of 59.5" each.

I have looked into passive radiators, but I didn't really want to spend more on them than I spent on the subs.

 

[Pallas]

Total Noob here, but I want to go for it….
Okay, Here is my build thread for two Alpine type R SWR 1020 Subs, but the only info I can find is for the 1021's, but so be it... I have found two net 1.5 cu. ft. boxes to use and come up with a Base Reflex port; 2"x10"x vent length of 53.5”. Is an abrupt folded vent bad?

Maybe, but the larger issue a vent that huge is going to have some nasty resonances.

Model it in Unibox or another program sophisticated enough to model port resonances as well. What you'll quickly learn is that the only good way to tune a small box low is to use a passive radiator.

 

[VolvoHeretic]

Thanks, Pallas for the insight. How about sizing a couple of 10" passives, one for each side, or one 12" for the back? The cheapest the better. Too bad the thread on DIY passive radiators ended without any being built and tested, I liked the one with an innertube for a surround.

I have been blessed with being turned onto Altec speakers since the '70's and now have two pairs, an EV Sentry IV II, and a PV T300 set of speakes, all of which need a little sub help. I would like to come up with a resonable cure-all for all of them.

 

[Pallas]

Thanks, Pallas for the insight. How about sizing a couple of 10" passives, one for each side, or one 12" for the back?

The only ones I've personally used are the Peerless XLS models, which are now more-or-less in production under the brand ScanSpeak Discovery. CSS has some too that look interesting, because one can alter their mass from the front.

Academically, one one each side is better, because then the movement of each cancels out, leaving the box more stable. But whether that matters in the real world is IMO an open question.

 

[OscarS]

what are you trying to tune these enclosures to?

 

[VolvoHeretic]

The vent length is calculated for 25hz for the 1.5 cu ft box. Ultimate is 1.3 cu ft at 28hz, I don't know what difference it makes. I would love for someone to calculate what I should build, I don't trust anything that WinISP comes up with...

 

[OscarS]

The problem is not really WinISD so long as you recognize it's abilities and inabilities, as it cannot account for everything. If you use a slot port inside the enclosure, where the port itself shares 3 of it's walls with the enclosure, for a given port area you can reduce the required port length to 60% of the calculated value and still achieve the target tuning. This is due to the extra end correction factor that WinISD cannot account for. I found this empirically in several enclosures I built.