Sonotube questions

[Jodean]

After reading abot more over 2 weeks or so now i plan on going the sonotube route.

I just bought some 18" sonotube and have gathered some info from other builds it will be about 5' 3" tall and use some 15" driver.......most of the builds i looked at had outdated and discontinued drivers so thats also a question now as which driver to match this enclosure. Ill reference the build when i have time to search and find it, just some quick questions for now though.

I havent seen any specs on the sonotube portion of any writeup ive read.

I think this is more important than any other specs of the build and no one so far has given any...

So next questions are:

1) The sonotube i got was 17 3/4" inside diameter and 1/4" wall. Is this sufficient?

2) anyone know if all sonotube are equal in tensil strength or other brands and are they even as stong as a square box 3/4" particle enclosure. I assume you dont want any give to keep the accurate tones.

3) Most drivers are only rated to 20 hz. I assume the design of the enclosure gets you below this? Or is there something else that determines that?

4) I have 6" pvc pipe for the port and it is also 1/4" wall. Hows pvc for tensil strengh?

[BoomieMCT]

Jodean wrote:

1) The sonotube i got was 17 3/4" inside diameter and 1/4" wall. Is this sufficient?

Yes.

Jodean wrote:

2) anyone know if all sonotube are equal in tensil strength or other brands and are they even as stong as a square box 3/4" particle enclosure. I assume you dont want any give to keep the accurate tones.

Basically, yes. There is a "quiktube" brand sold at Lowes that is considerably thinner. I've not heard of anyone using it without doubling it up.

Jodean wrote:

3) Most drivers are only rated to 20 hz. I assume the design of the enclosure gets you below this? Or is there something else that determines that?

I'm not sure what you mean by "rated" but ports or passive radiators allow you to play below the Fs of a driver.

Jodean wrote:

4) I have 6" pvc pipe for the port and it is also 1/4" wall. Hows pvc for tensil strengh?

PVC has a tensile yield strength of about 6000psi. For ports stiffness is more important and 6" PVC is plenty stiff.

[Jodean]

Ok i found the inspiration for my build

http://dustin.bunnyhug.net/sonostart.php

1) So what tempest driver is he using and where do i find it?

Any other suggestions for drivers? Would like to stay in the 15" and in the $120 price range.

All i can find is Dayton subs at parts express.....

2) where are the others at?

3) If i get a dvc 8 ohm or 4 ohm......can i get by with 80w (8 ohm) per coil for now until i find an amp? I have an old sansui im currently using to power my sub.

Oh i think i get it now....it WAS the adire audio that is no longer? After more searching...apparntly there are ALOT of subs that are no longer.

[BoomieMCT]

Isn't the Dayton DVC the same thing as the old Adire Tempest? I could be wrong.

[Joe L.]

BoomieMCT wrote:

Isn't the Dayton DVC the same thing as the old Adire Tempest? I could be wrong.

Pretty sure your memory is correct. Their specs were very similar, and they were considered interchangeable in most designs.

I used a Tempest in a 260L 18" diameter Sonotube. Its wall thickness was as you described. Don't worry, if it can stand up to the pressure of a 12 foot column of cement, it can easily deal with a bit of low frequency sound.

Design: Ported, tuned to just under 17 Hz
Enclosure: 260L 18" diameter sonotube 66 3/4 tall, total height 77 1/4 inches with end-plates on both top and bottom.
Driver: 15" Adire Tempest, dual 8 ohm voicecoils, wired in parallel for a 4 ohm load to the amplifier. 2.5L displacement
Amp: 250 watt PartsExpress plate amp (no bass boost)
EQ: BFD Parametric Equalizer
Total Cost: + or - $350 (includes driver, amp,paint, MDF, sonotube, fabric. BFD added $100 more on top of that.)



Frequency response at my listening position, before I equalized the response with the BFD. Rx crossover was set to 80Hz, that is why top end drops off the way it does. I had disconnected my mains when I measured the response of the sub:


My Tempest based sonosub now sits unused at the rear of my theater... Every once in a while, my wife asks me what I'm going to do with it... It has been replaced with a pair or sealed 12.5 cubic foot subs, each with an 18" Ascendant Avalanche driver.

FYI: That same site (http://dustin.bunnyhug.net/sonostart.php) was the inspiration for my project...

Joe L.

[thomas2717]

2) where are the others at?

Adire is now defunct ~ Tempest may not be available per se. But some of the folks from adire, have resurrected the Tempest & Shiva drivers and are available via Acoustic-Visions.com (Kyle Richardson) or DiyCable.com.

Also, Mach5 Audio has had great reviews for Quality SQ subs!

Have not used these subs - but just wanted to pass on the info.

[thomas2717]

PS: I own a Dayton Titanic in a sealed box - I am definitely not using it to the max potential. I am hoping to go the Sonotube route myself in the near future..

[thomas2717]

Nice lookin sub - Joe!

[Joe L.]

Jodean wrote:

3) If i get a dvc 8 ohm or 4 ohm......can i get by with 80w (8 ohm) per coil for now until i find an amp? I have an old sansui im currently using to power my sub.

Yes... it would work until you upgrade.
You would need to put two sets of binding posts on the sub enclosure, one for each voicecoil, as I'm certain the Sansui amplifier would not allow you to bridge the outputs.

That's not really a show-stopper... Just something to remember as you start your parts orders.

Dual 8 ohm voicecoils are probably your best bet. That way you could feed each with a channel of your amplifier. If your amplifier can handle 4 ohm loads, then dual 4 ohm voice-coils might work for you too. They just make it a lot harder if you upgrade the amplifier to a single channel plate amplifier.

Two 4 ohm coils in series would be equal to 8 ohms... a good load for a lot of plate-amplifiers, but an amplifier like mine, rated at 250 watts into 4 ohms only outputs about 150 or so into 8 ohms. The odds are you will not get the full output you might expect. (possibly not much better than your existing Sansui amp)

Two 4 ohm voicecoils in parallel would be a 2 ohm load, far too low for most plate amplifiers.

So, dual 4 ohm voicecoils are OK, but not a good match to a single channel plate amplifier. They would work ok with a "Pro" amplifier that can handle bridging, or 2 ohm loads.

On the other hand, two 8 ohm voicecoils in parallel are equal to a 4 ohm load. Perfect for most plate-amplifiers as a 4 ohm load and (wired separately as two 8 ohm loads) usable with your current amplifier. Just something else to think about as you shop for materials.

Joe L.

[Jodean]

Wow.... the Tempest X has 27mm of xmax?? The dayton has 15.1mm

Is there that much difference and worth the extra $60?

Thats almost double the movement......

[BoomieMCT]

Jodean wrote:

Wow.... the Tempest X has 27mm of xmax?? The dayton has 15.1mm

Is there that much difference and worth the extra $60?

Thats almost double the movement......

More is better BUT xmax isn't everything. Other parameters like Fs and efficiency can be just as important. Ported subs often are not as dependant on xmax as sealed ones. Also, twice the xmax sounds like a lot (and it is) but remember that excursion has to quadruple for each additional octave down you go. All that being said, more xmax is always nice to have.

As to whether the Tempest-X (with it's superior xmax) is worth $60 more to you is a question only you can answer. I'd suggest modelling both in WinISD or Unibox, checking cone excursion and output and seeing if you need the extra capability for what you are trying to do.

[Joe L.]

BoomieMCT wrote:

As to whether the Tempest-X (with it's superior xmax) is worth $60 more to you is a question only you can answer. I'd suggest modelling both in WinISD or Unibox, checking cone excursion and output and seeing if you need the extra capability for what you are trying to do.

If the difference is only $60, to me it is a no-brainer... especially where is another huge difference not yet mentioned, that is the XBL-2 design of the Tempest-X. It results in a far lower distortion sub than the Dayton DVC at larger excursions.

As already said, to reproduce low frequency sounds you need to be able to move a lot of air. Every octave lower you go, you need 4 times the displacement to get the same sound pressure level. (Yes, you are pressurizing the air in the room)

There is no replacement for displacement. One of the reasons my Sonosub is now sitting in the rear of my theater is that it could not keep up with the more dramatic low frequency effects on some of the movies out these days. "War-Of-The-Worlds" bottomed out the Tempest based sonosub if I turned the volume up much.

I had a choice, either add a high-pass filter to cut everything below my 17Hz tuning frequency out, or to build a new sub that could handle everything. I elected to build new. I went from the 2.5 Liter displacement of the single 15" Tempest to a pair of 18" drivers, each with 6.5 Liters displacement, in sealed enclosures...(high excursion below port tuning is not an issue in a sealed enclosure)

Now, don't get me wrong... My Tempest based sonosub is not a slouch. It easily will outdo anything I've ever seen in any store. You could build your sub using a Dayton DVC, and be very very happy. You may not even have any issue until you replace your Sansui amplifier with one that has a frequency response that gets down into the teens. The Sansui may have a natural "high pass filter" Its frequency response probably only goes down to 20 Hz or so and falls off below that.

As I said, if the difference is only $60, to me it is a no-brainer... compared to the rest of the effort and costs involved in building the sub, I think it is very much worth the $60 to use the driver with the more advanced design, lower distortion, and higher x-max. When I built my Tempest based sonosub, in 2003, the high-excursion XBL-2 alternative did not exist... if it did, I probably would not have had the need to upgrade.

Joe L.

[BoomieMCT]

Joe L. wrote:

Now, don't get me wrong... My Tempest based sonosub is not a slouch. It easily will outdo anything I've ever seen in any store.

You should simplify the issue and just sell Jodean your unused Tempest sub! Win-Win!

In all seriousness, I mostly agree with Joe L. and if I were making a sub I'd probably use the Tempest-X over the DVC. There are some considerations where that statement isn't true however. One is if cost is very tight. I've made $150 sonosubs and in cases like that $60 represents a large part of the total budget. Another would be if the DVC happened to model better in a particular configuration (haven't modeled both so this is a "what if"). I've heard the Dayton DVC work very well in TL enclosures - no idea about the Tempest-X. The third is if there was some sale that dropped the price of one way below the other (see reason #1).

[Jodean]

BoomieMCT wrote:

You should simplify the issue and just sell Jodean your unused Tempest sub! Win-Win!

).

I actually saw that when he first posted but then saw that he was in NC.....a little more than a drive!!

I think its a no brainer either, so for the $60 ill probrably get the tempest. Right now i cant afford either one but theres always credit cards....hopefully we get that tax rebate.....$1200 should buy some nice stuff!!

[Joe L.]

BoomieMCT wrote:

You should simplify the issue and just sell Jodean your unused Tempest sub! Win-Win!

If he was local, it would be a possibility. Unfortunately, I think he in in South Dakota, and I am in North Carolina. Shipping would be very expensive as I'm guessing it is "oversize" for UPS, Fed-Ex...

In all seriousness, I mostly agree with Joe L. and if I were making a sub I'd probably use the Tempest-X over the DVC. There are some considerations where that statement isn't true however. One is if cost is very tight. I've made $150 sonosubs and in cases like that $60 represents a large part of the total budget. Another would be if the DVC happened to model better in a particular configuration (haven't modeled both so this is a "what if"). I've heard the Dayton DVC work very well in TL enclosures - no idea about the Tempest-X. The third is if there was some sale that dropped the price of one way below the other (see reason #1).

No argument about some considerations. If he is trying to save money, and build on a very tight budget, then $60 more might be a lot to ask. One clue might be his desire to use his existing amplifier in the short term. Money might be an issue. On the other hand, it might eliminate a need to upgrade later, only he can tell. We do not know the size of the room, or the SPL needed, or even if it is for Movies, where high SPL LFE events occur, or Music, where they do not.

Either way, with the Tempest-X, or the Dayton DVC, the result will be far better than anything you see at Circuit-City or Best-Buy and probably better than most you will see at a mid-level Hi-Fi specialty store. (High-end store might carry a high-end sub, but that will be way more than the $60. difference in cost and may just be a trade-off in size, efficiency, and SPL at that. Smaller box, higher power amp to compensate... Hoffmann's Iron Law at work.)

I can tell you one thing, once you get used to decent bass it is impossible to walk through Circuit-City or Best-Buy and not notice how bad most of their displays sound. Granted, they are trying to pressurize a much larger room, but even near-field, their offerings sound anemic. It is as if I am watching a completely different movie when at home. The low bass makes that huge a difference. Yes, I'm spoiled... but that is OK...

Joe L.

I currently have two 18" Ascendant Audio drivers, each in their own sealed 12.5 cubic foot enclosure, each fed by one channel of an EP-2500 pro-amplifier, for roughly 700 watts per driver. Total displacement is 13L.

[BoomieMCT]

Joe L. wrote:

Either way, with the Tempest-X, or the Dayton DVC, the result will be far better than anything you see at Circuit-City or Best-Buy and probably better than most you will see at a mid-level Hi-Fi specialty store.

I can tell you one thing, once you get used to decent bass it is impossible to walk through Circuit-City or Best-Buy and not notice how bad most of their displays sound.

Big 'ol +1 on this. I made a cheap ($150) sonosub for my brother. It had a large (by commercial standards) enclosure but a cheap $35 Dayton driver and a 70 watt amp. It wasn't super loud but could hang with most comparable commercial subs and easily fills my bro's living room. The sound quality was way beyond what you could get for $150 at a store.

Many people bring their subs to me when they break so I've had the opportunity to analyze many brands builds. In general I'm dismayed by the quality of the drivers (considering the price) and the quality of the enclosure material / construction. In most cases when an amp isn't salvagable I don't even want to use the leftover parts for a DIY build. Many of the drivers end up as refrigerator magnets (much to my wife's dismay).

[Joe L.]

BoomieMCT wrote:

Big 'ol +1 on this. I made a cheap ($150) sonosub for my brother. It had a large (by commercial standards) enclosure but a cheap $35 Dayton driver and a 70 watt amp. It wasn't super loud but could hang with most comparable commercial subs and easily fills my bro's living room. The sound quality was way beyond what you could get for $150 at a store.

Nice job. Looks like the little brother of mine. I like how it hides behind the TV.

Many people bring their subs to me when they break
<snip>
Many of the drivers end up as refrigerator magnets (much to my wife's dismay).

You have a very understanding wife... much more understanding than mine. I got tired of the tiny refrigerator magnets she collected and purchased a dozen of 3/8 inch diameter neodymium magnets for use on the fridge. They easily hold anything I put under them. On the other hand, I guess your subwoofer salvaged magnets can hold a few sheets of paper too.

Joe L.

[BoomieMCT]

Joe L. wrote:

Nice job. Looks like the little brother of mine. I like how it hides behind the TV.

You have a very understanding wife... much more understanding than mine. I got tired of the tiny refrigerator magnets she collected and purchased a dozen of 3/8 inch diameter neodymium magnets for use on the fridge. They easily hold anything I put under them. On the other hand, I guess your subwoofer salvaged magnets can hold a few sheets of paper too.

Joe L.

Yeah, my wife had decorative magnets that could barely hold 1 piece of paper. The tweeter and small driver magnets easily hold pieces of paper, cupons, advertisements, etc. The sub magnets hold whole pads of paper (for grocery lists and such). They are great! Nowadays she makes me remove the magnets on the big ones instead of sticking the whole motor assembly.

[BoomieMCT]

Just to add pictures to what we were saying here are FR and excursion plots for the Tempest-X and the 15" Dayton DVC. I kept enclosure size the same (250L) and amp power the same (500 watts). Tuning was different. As you can see the DVC will hit overexcursion and the Tempest-X really doesn't. So even without the XBL^2 the Tempest would have a distortion advantage. The DVC does have one advantage that at a comparable power level it is almost 3dB more efficient.

[Jodean]

Ahhh...didnt know i forgot to tell room dimesions and use. Must have been another thread i had started.

anyway the room is 18x22x7'-10" concrete floor with carpet and pad and the use is for HT.

dang i see they are cheaper if you buy two of them.....i already have 10' of sonotube which i couldnt afford now either but seeing how normally id have to buy the whole 12' and i happened to be there to buy a damaged one i had to get it.

I didnt plan on being broke but most people get a second mortgage to finish their basement i tried to do it out of pocket and it worked pretty good till the carpet and window treatments went in.....then i had nothing left. By summer ill be back in the buying mode.