Home Theater Subwoofer - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 30th October 2001, 07:44 AM   #1
Myren is offline Myren  United States
diyAudio Member
 
Join Date: Oct 2001
Location: Maryland
Send a message via ICQ to Myren Send a message via AIM to Myren
I used to have grand plans for a Adire Audio Shiva, but I'm starting to get the perception that it wasnt really intended for home theater. Although I do like the price tag.

Anyone able to recommend some top of the line woofers? Size is no object, really. Oddly enough, bigger is better to many extents. Needs to cover 20 hz decently, provide at least a minimum amount of kick. Something to that serves to the weaknesses of two 21W8555-01's 0.5 Q box.

Oh, and what are acoustic's golden ratios again (just need the #'s)? Applies for both sealed and ported?

Thanks
Myren
  Reply With Quote
Old 30th October 2001, 08:26 AM   #2
Myren is offline Myren  United States
diyAudio Member
 
Join Date: Oct 2001
Location: Maryland
Send a message via ICQ to Myren Send a message via AIM to Myren
I was doing some further research, and I discovered this: Adire Adui's new 18 inch subwoofer driver <a href="http://adireaudio.com/cd/maelstrom.htm">the Maelstrom</a>. Heavy duty.

Anyone with actual expertise care to make heads or tails of it? Looks like its geared towards more profesional solutions than the Shiva. Size optimizations, thankfully, went out the window. I'm starting to considering it a worthy investment, possibly the driver I'm looking for.

Any commentary? Competitors I should checkout?
  Reply With Quote
Old 31st October 2001, 04:36 AM   #3
Ignite is offline Ignite  Canada
diyAudio Member
 
Join Date: Jul 2001
Location: Toronto, Ontario, Canada
Send a message via ICQ to Ignite
A vented shiva is my HT sub. It is one of the deepest subs I've ever heard. High xmax lets you reproduce that LFE channel without as much bottoming-out as sometimes happens with other products. The ACI SV12, Dayton Titanic and NHT 1259 are other popular choices, but I've found they all sound great, so go for the one you prefer.

Be careful with the Maelstrom. Large subwoofertstend to produce more "loose" bass, and to get decent extension into 20-30Hz range you're going to need a huge enclosure. Typically you will have better results with multiple 12" drivers than a single larger driver.

I know some members here would never buy a foam surround loudspeaker, but I have had no problems with the Shiva. It is more cheaply constructed than others, so it might not last forever. But as you said, the price is right. As a student I don't have a lot of spare money, most of my income goes directly into tuition. So the shiva was a great choice.

If you're stuck on a sealed enclosure you might want to try one of the other drivers, they tend to have slightly deeper bass. The NHT 1259 and Dayton Titanic 1200 are optimized for sealed enclosures.

The SV12 is also a good choice. A very large vented enclosure with the SV12 (extended bass shelf) yields almost no dropoff until 25Hz, reaching F3 at 17.5Hz. However, it would have to be very large.

Shivas offer better response in smaller vented enclosures than the SV12. They also have also dual voice coils, which gives you some more options in amplification than other drivers.


Essentially it's up to you. Any of those in a properly designed and constructed enclosure would produce quite impressive sound for home theatre purposes.
  Reply With Quote
Old 31st October 2001, 05:10 AM   #4
diyAudio Member
 
Join Date: Feb 2001
Location: Columbia, SC
Ignite perhaps refers to me when he mentions folks having reservations about foam surrounds. In my experience the foam lasts at least 5 years at a minimum, averages about 10 years or so; I can't recall ever seeing a foam surround last more than about 12-15 years.
Most people don't look that far ahead, but I've found that I tend to keep things for a long time (I still have speakers I bought in the '70s, for instance--including some that have had to have woofers replaced due to...you guessed it...rotted foam surrounds). It's up to you.
He is also correct in listing other drivers in the same class, all of which will give similar performance. I'm sure you'll be happy, sound quality-wise, with any of them. I know Bryan is pretty smug about the sound of his new sub--which houses a Shiva. Note that I don't doubt the sound quality of a driver with a foam surround, only its long term reliability.
******
Another of my periodic philosophic ramblings...
Where, oh where did this silly notion ever get started that there is a division between home theater subs and subs intended for listening to music? I assume that some crafty marketing type realized that they could sell twice as many subs if they managed to convince people that they needed a separate one for each use. Unfortunately, once an idea like that becomes common, it's hard to eradicate it.
If you think about it, you'll see that the requirements are identical. High spl (assuming that the source material demands it). Accuracy. Flat response. Depth. And to a lesser extent, efficiency. Nowhere in that list is there a conflict between HT and music. A sub that does well in one category will do well in the other.
Design and build the best subwoofer that you can afford, then live with it happily for all uses.

Grey
  Reply With Quote
Old 31st October 2001, 09:17 AM   #5
Myren is offline Myren  United States
diyAudio Member
 
Join Date: Oct 2001
Location: Maryland
Send a message via ICQ to Myren Send a message via AIM to Myren
Foam surrounds: they may wear out, but you can always replace them. So far, I've replaced surrounds on three pairs of speakers. Something I dont mind doing every 10 years.

I agree with the oversize issue. I'm considering going for daul SV12's or dual Shiva's in a mechanically-parallel ported system, optimized for a nice sinfully low cutoff frequency, depending on how hard it is to implement dual drivers. Anyone know of good sites for information on dual drivers?

From the raw cuteness point, not really knowing what acoustically it does, I'm thinking of doing what <a href="http://www.libinst.com/LspCAD.htm">lspCAD</a> calls a Bandpass Box Type 4, with two subwoofers on independent side chambers firing into a center chamber, with all three chambers being ported.

I'm a little pissed that I'm going to end up with 8 ohms resistance. The <a href="http://apexjr.com/Apexsenior.htm">amp</a> I was planning on buying for it only runs 250 watts RMS at 8 ohms. Fooey. Would that make it worth abandoning the dual driver plan?

Oh, and does the shape of the port matter? I've seen a couple "mailbox" / "mailslot" designs cropping up utilizing a slot across the top of the box.

[Edited by Myren on 10-31-2001 at 05:24 AM]
  Reply With Quote
Old 31st October 2001, 05:52 PM   #6
diyAudio Member
 
Join Date: Oct 2001
Location: 5280'
Myren

The current best bang for the $$$ in high excursion drivers is the BP1503. This an extremely good driver and the price is right. It won't plumb the lowest depths like multiple Tempest's or PE DVC 15"s. But it will reproduce clean and astounding high output down to 18Hz when used in a proper box.

Next in line $$, is either the Tempest or PE DVC 15". Although not identical these have very similar performance characteristics.

Current foam surround technology has a life span of roughly 15 years according to the driver mfgrs, and it's more linear than rubber = less distortion.

All of the drivers listed above use a carbon fiber layer epoxied to a formed paper cone (=very stiff). As a result there are almost no issues with the cone becoming nonlinear/less pistonic when driven hard.

IMO bandpass designs don't provide flat response or good sound quality. Go with either a sealed or ported design

Regarding the large drivers = loose/ slow bass that's bunk. If the T/S parameters of a 12" and 15" driver are the same, the drivers are just as fast/tight. This is true for 18" units as well.

Round ports are much easier to tune/adjust and they can be used with flares. Flares drastically increase the air flow from ports = decrease potential of chuffing/port compression. As a result 3" flared port moves as much air as a 4" straight port. This situation is the same for larger flared port sizes to.

Finally a single 15" will displace almost as much volume as 2-12"s, and the cost is much less.

The old saying 'there's no replacement for displacement' still hold true.
  Reply With Quote
Old 31st October 2001, 07:56 PM   #7
Super is offline Super  United States
diyAudio Member
 
Join Date: May 2001
Location: Connecticut
Send a message via AIM to Super
Just thought I'd comment on the Shiva. I made a ported sonosub using a single driver, which is linear to below 20 hz, and is about 6db down at 16hz. I partnered it with the AVA-250 sub amp from Adire, and I've yet to surpass the half way mark for the output because the amount of bass can easily overpower all other channels without even being up 1/3 of the way. I also use it for music, where it integrates seamlessly with my mains. If you want abnormally high SPL's, then make sure the rest of your equipment, including (especially!) your listening room is up to the task.

Yes, the Shiva does have a foam surround, which will rot out eventually, but not for many years to come, and by then, I'm sure I'll just go ahead and build a new sub with a new driver, because odds are driver technology will have changed quite a bit within the next decade. So unless you want to build the last sub you're ever going to build, the Shiva is an excellent driver regardless of its foam surround. As for me, its safe to say there will be many more subs and loudspeakers to come, so I'm not too concerned as to whether or not my whopping $450 in parts will hold up for 10 years. It's as good as it gets for me right now, and was well worth the investment.

And I definitely agree with Grey. There shouldn't be anything that defines a sub as one for home theater or music. If its what it should be for music (well rounded), then it should perform equally as well for HT. If it doesn't, then it's not a good sub.
__________________
Bryan
  Reply With Quote
Old 2nd November 2001, 08:45 PM   #8
Ignite is offline Ignite  Canada
diyAudio Member
 
Join Date: Jul 2001
Location: Toronto, Ontario, Canada
Send a message via ICQ to Ignite
Perhaps size doesn't change the tightness of bass. But the Maelstrom does have quite different T/S parameters. It begins to drop off in response very quickly, and frankly needs a HUGE enclosure. I was playing around earlier with using an ACI SV10 for a small sub for a small system I have. Instead I've decided to use my current shiva for it and build a sealed 4.5cu ft Tempest. With a bit of equalization I can give it flat in-room response well below 20Hz. I was a little dissapointed with the "tightness" of the vented shiva. It had rather high group delay nearing 20Hz, so that's to be expected. I hope this sub will be really tight.
  Reply With Quote
Old 2nd November 2001, 09:48 PM   #9
Myren is offline Myren  United States
diyAudio Member
 
Join Date: Oct 2001
Location: Maryland
Send a message via ICQ to Myren Send a message via AIM to Myren
Given the massive enclosure, is the Maelstrom a worthwhile driver? Again, I'm actually almost hoping for a large subwoofer, something to match my computer's supercooler. Need to fill in that under the bed space (elevated bed).

Is there any simple day to do dual drivers? What do I need to adjust for the parameters for dual drivers? Any good websites with info on dual drivers?

Thanks
Matt
  Reply With Quote
Old 2nd November 2001, 09:54 PM   #10
Ignite is offline Ignite  Canada
diyAudio Member
 
Join Date: Jul 2001
Location: Toronto, Ontario, Canada
Send a message via ICQ to Ignite
Default Dual drivers

2 x cabinet volume
2 x port mach (if ported)
Common sense applies. Amplification:
2 in parallel: half impedance
2 in series: double impedance.

It's pretty simple.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Custom Home Theater Project in New Home, Opinions appreciated. thadman Multi-Way 5 20th November 2008 12:40 AM
Help me build a Home Theater subwoofer rocko1290 Subwoofers 3 1st September 2006 08:53 PM
Car amp in home theater? JWFokker Car Audio 4 29th April 2005 01:47 AM
Home Theater PC F/S vdi_nenna Swap Meet 0 23rd June 2003 01:07 PM
TL in home theater? hunter Multi-Way 4 8th July 2002 09:10 AM


New To Site? Need Help?

All times are GMT. The time now is 09:27 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2