Don't know which driver to choose

[ChrisJee]

Hi there!

I need help and advice (and maybe your opinion!) for the project I want to start and I think I'm at the right place! So here I go...

As I said in my intro, I plan to build two passive subs for my home theater system for filling the lack of bass from my main speakers (Altec Lansing Model 85). These subs will be driven by an external stereo power amp (an old LXI Series Model AM4222 - made by Sears in the 80's I think) which will be connected (with a Y-cable) to the mono low pass jack of my digital sound processor unit (an old but still working great Yamaha DSP-E1000).

For the two subs I want to build, I have an old pair of 3-ways vented speakers that I want to modify. All the drivers are defective and I have already removed them. I prefer sealed (by sealing well the actual port and the tweeter's and mid's holds) but if I can go ported by using or modifying the existent port, I'll go. The port is D=62mm(2,44") and L=76mm(3").

Each box is about 67 liters (2,37 ft^3) internal and after putting the numbers in a spread sheet (for sealed alignment with Qtot=0,707), I found that and I have the choice between three 12" drivers from a local dealer here in Quebec City (I thing they order from Q-components in Waterloo, Ontario - www.loudspeakers.ca):

- Philips AD12240W8 8ohms (Vb=2,24 ft^3 ; Fb=61,3)
- Pioneer A30FU20-52F 8ohms (Vb=2,43 ft^3 ; Fb=68,4)
- Pioneer A30FU20-53FQ 8ohms (Vb=2,24 ft^3 ; Fb=63,9)

Have you eared something about these drivers? Do you have something else to suggest me?

By my side, I had a look at Solen's website (I wrote them too) and they suggested me some drivers for a ported box alignment but the price is too high for my budget... I don't want to spend no more than 200$ CAD (~175$ US) for this project (including Xover parts) and of course, I must order from Canada because the last time I ordered from the USA, it cost me 50% the price of my purchase only in shipping and handling!

Waiting for some help/advice/opinion from you and thank you in advance for your reply!!!

[Lothar34]

I don't know anything about those drivers, but one thing I would suggest is just making an entirely new baffle instead of sealing up the holes in the current one.

The current one is probably particle board and probably 1/2" (or 3/4" if you're lucky). You should just make a new one from 3/4" MDF. Taking off the current baffle will make it easier to put some extra bracing in there too.

Doesn't Parts Express have reasonable shipping to Canada?


Also, if you're going to remove the baffle you can seal it off anywhere you want in there, so you can lower the volume of the enclosure by making a "false top".

[ChrisJee]

Thanks Lothar34 for your reply!

This is something I never think about ... removing the current baffle ... I'll try this and make a new one. But for now, I'm very busy at home (getting ready for fall and winter)... So it will take a moment to do the mods...

And yes, the baffle is particle board and I'm very lucky because it's 3/4"!!! But if I have to remove it, I'm not so locky at all!!!

I ordered only once from PE and it's this order that cost me 50% the total (50$) of my purchase for shipping (25$)... So, if I want to save some money, I think it's a good idea for me to order from Canada...

BTW, on Solen website, I had a look on their "Woofer Enclosure Suggestion" page and I found that I have the choice between some Peerless, Seas, Silverflute or Vifa woofers. Is there a brand better than an other?

[Lothar34]

Peerless makes very good subs. I would imagine that Seas and Vifa do too, and I don't know about Silver Flute. The only Silver Flutes I've seen were on Madisound's site and they only went up to 8".

[CarlosT]

Can you buy from Parts Express in Ohio? They're right "over the border"

[ChrisJee]

CarlosT:
I'm a little bit away from the border and more than 940 miles north-east from Dayton, Ohio! It will cost me a lot of gasoline to go buying there!

Lothar34:
I think the home is almost ready for wintertime and maybe I'll start cutting my old front baffle next week and bracing the boxes. I found that these 2 drivers will meet with my goals for my sealed boxes. The first one is from Solen (the T/S parameters are from their website too) and the other is from Q Components (I think my local dealer can order from them - the T/S parameters are from www.thielesmall.com and the Q Components's electronic catalog) :

Model = Seas CA25RE408 (26cm=10")
VC dia = 39 mm (1.54")
Type = Paper Cone
SPL = 89 dB (2.8V)
Power = 80 W (RMS or Peak?)
Znom = 8 ohms
Re = 5.8 ohms
Le = 1.6 mH
Ce = 47 uF
Fs = 24 Hz
Vas = 189 liters (6.67 ft^3)
Qms = 3.8
Qes = .39
Qts = .35
Xmax = +/- 4.0 mm
Sd = ?
Mms = ?
******************************************
Model = Pioneer A30FU20-53F-Q (30.6cm=12")
VC dia = 38.1 mm (1.5")
Type = Poly Cone
SPL = 94 dB
Pmax = 60 W (90 W in the Q-Components's electronic catalog)
Znom = 8 ohms
Re = 5.6 ohms
Le = 0.001 (mH or H?)
Ce = ?
Fs = 28 Hz
Vas = 266.2 liters (9.4 ft^3)
Qms = 3.71
Qes = 0.34
Qts = 0.3115
Xmax = 2.4 mm
Sd = 0.0546 m^2
Mms = 50.66 (grams I think)

I put these numbers in an Excel spreadsheet (ported.xls from Brian Steele's website - www.diysubwoofers.org) and for my desired Vb of 67L (sealed box), it gave me these values:

For the Seas : Fb=46.9 Hz; F3=48.5 Hz; Q=0.68
For the Pioneer : Fb=62.4 Hz; F3=63.9 Hz; Q=0.69

In my opinion, I think the Seas is better (lower F3, same Q) byt should I have to consider other values (or modeling these drivers with WinISD or SubSim or another prog) before making a choice?

Thank you in advance for your help and advice!

[Lothar34]

Of those two, I'd go with the Seas.

Mostly because I like paper cones on my woofers though.

[ChrisJee]

Thanks for your advice but again ... a dilemma!

I found (on the Solen website again! ) that the Peerless S263SWR3908 can also do the job. For my 67L box, I have Fb=47 Hz, F3=45.8 Hz, Q=0.73 and for a maximally flat setting (Q=0.707), I have Vb=74.8L; Fb=F3=45.8 Hz. The price is lower than the Seas and the power is higher (220 watts instead of 80). In my opinion, I should go for the Peerless!

But, here is my question (there's always a question! ):

Knowing that my stereo power amp is 75 watts per channel, what drivers should I choose? Supposing that one day I want to crank my amp up , choosing the Seas (2*80W), is there a chance blowing them? In the other way, choosing the Peerless (2*220W), is there a chance blowing my amp?

I'm a little bit confuse... Is it better having drivers with power rating higher than the amp or having amp with power rating higher than the drivers?

Sorry if I'm boring you with such a question but I have so much to learn!

Thanks again for your answer!

[ChrisJee]

Hi Lothar34,

Finally, I ordered two Peerless SLS 10" (830668) from Solen and I received them last friday! I hooked them up to my power amp (setting the LFE-volume as low as possible on my DSP unit), put a CD-tone that I made (10-150hz) with a little software in my DVD player, hit the PLAY button and TA-DAAA! I heard all the tones! I'm now sure that they're not DOA!

But for now, I'm in a dilemma... I don't know what to do with my actual sealed box (67L)...

On the Tymphany website (http://www.tymphany.com/datasheet/appview.php?id=37), they suggest a 42L sealed box, Fill=65% and F3=52.7Hz.

On the Solen website (http://www.solen.ca/woofapp.htm), they suggest a 75L sealed box with F3=46Hz (filling is not specified).

But with UniBox in the Closed Box section, at the Damping/Leakage scrolling lists, I choose Walls covered/Minimal leaks and a Wanted Qtc=0.7095. I hit the Start button to optimise Vb for wanted Qtc and it gave me these values in the attach file below...

Is it true to say that if I add damping material to my box, the volume "seen" by the driver will be greater then the physical volume?

If yes, I think I'll go with the UniBox's numbers because they are very similar to those I want!

Is there anything else that I must take into consideration before modifying my box and putting all the stuff together?

Thank you in advance for your reply and/or your advice/opinion!

Note: If you try the numbers (from Tymphany) in UniBox, don't forget to enter values for the 100hz external passive crossover I want to build (Lco1=18mH, Rco1=0.24ohm, Cco1=141uF) and to check the corresponding box in the Drive Unit Configuration.

[looneybomber]

I am too late. I was going to tell you about www.mach5audio.com since they're based out of canada.

As for your box, you're usually safe with a 50% fill in most cases, but get advise from someone else on this. They will probably have an exact answer for you.