1 or 2 Titanic MKIII 15 kits or PC Ultra?

[BobbyT]

Sorry for all of the questions but when I buy my new speakers and sub it will be the last purchase for a long time.

OK my other post has given me something new to think about. With music the priority but movie performence also important. Would a pair of the 15" Titanic kits with polyfill stuffing deliver the performance I'm looking for or would I be better off with the 1 PC Ultra? Am I really going to be missing that much in movies opposed to what I get for music. This will be paired with 2 RF7s and a RC7.

I am already familiar with Dayton as I have a 12"DVC powered by a 250 parts express amp.

[michael hurd]

I have heard a pair of the CS-ultra's. Impressive, but I think that given the choice between a PC-ultra and a pair of the dayton 15" titanics, I would lean towards the titanics. Given that fact that the 2 15" cones have a lot more surface area, they will need less excursion to produce the same volume as one 12". You can also play with the eq on the parts express amps, to eq the bottom end.

Assuming you have the room, can stack and corner load them, I would say go for the Dayton's.

[Scp53]

I would also vote the titanics. with two(or one for that matter) you should get pretty decent depth for a sealed cab and tightness for music if placed right. I think that one 15" can displace about two 12 with same x max. Another option would be getting a pair of avalanche 15in drivers from ascendant audio and a 1000watt PE plate amp. Do you have the ability to do DIY? the two 15 would cost $300 each so thats $600. The amp will cost like $400 and a cab 50 with a nice finish. So thats will cost ya around $1100. each 15 would go in a 4cu ft box. just a thought. but other wise the titanics are the best option.

scp53

[DrWho]

If you go for the Titanic (especially 2), then I would highly recommend building your own enclosures. They provide the necesary details on the website:

15" Titanic MKIII vented subwoofer box design (40 kB PDF)

15" Titanic MKIII sealed subwoofer box design (36 kB PDF)

You'll notice that the sealed cabinet is -12dB at 20Hz, where the ported cabinet is -6dB at 20Hz.

Max SPL @ 20Hz:

-Sealed = 105dB (800 watts)

-Ported = 111dB (800 watts)

The ported cabinet would be a 2 x 2 x 2 ft box versus the 1.5 x 1.5 x 1.5 ft of the sealed cabinet. Not sure if that makes a big difference in your situation.

So two plate amps would be $600 and then two drivers would be $200 and then add on maybe another $200 to build and finish the cabinets (I was able to build my last subwoofer cabinet for free...just find someone who does construction for a living to save you some scrap wood). So that comes to $1000 versus the $1376, and you'll end up with a better performing speaker. A while ago I went to a local car audio installation place, and they offered to build me some slightly smaller cabinets for $100 each totally finished. So that might be an option to look into as well (especially if you're like me and have no woodworking skills).

Now all that said, the pc-ultra is going to cost you $1200 and is going to give you response down to 16Hz (quarter octave below the titanic). I'm not sure what the max SPLs will be, but I'm sure both will have no problems at normal listening levels. I think the Titanic will be more musical than the SVS, but I've never heard either so that's my uneducated opinion. I just notice a trend that front firing subs seem to have more punch (aka more musical) than the downfiring kind, where it's more about the rumbling (good for HT).

I personally would go for the Titanics because the dual sub approach gives you some placement options to battle the room's acoustics, and I like to build stuff. Because you'll be using two subs, you could probably tune the cabinets a little bit lower to get lower extension (at the price of SPL, but you'll already be pushing 115dB). If you're creative about it, you could build a cabinet where you adjust the tuning of the cabinet by plugging ports. Then you can switch back and forth between movie and music mode.

[dragonfyr]

Here's a radical idea, and one that I wish more readers would start demanding from the manufacturers!!!!

Now the 'wattage' of a speaker is very useful! I know it is for me, as it is very important for me to determine the heat load in a room. This aids in determining the amount that I can downsize my heating system and how much I have to beef up my air conditioning. That added to the other sources and sinks can provide a pretty accurate thermal portrait of the acoustical space, not to mention the heating effect that the addition of so many of the discussions that focus on this aspect contribute!

But wouldn't it be nice if you had he complete parameters of each speaker? The ETC curves, waterfall plots, the polar response, Nyquist/Heyser spirals, etc.

Funny, as most, if not all the major manufacturers have and employ a TEF, or at the very least, MLS measurement systems! I know! They now show up at the Loudspeaker Design Seminars! For instance, Klipsch has been there since at least 1990 in Atlanta! But have we ever seen any of the plots that they could easily provide? (and if they provide them, I apologize except to the extent that they are not included routinely with the product specs!) Instead we get a sensitivity rating,nominal impedance, wattage (how good a heater they are!), and a frequency response. Whoopee!

From the complete set of meaningful specs you could accurately compare two speakers. You could also make some preliminary determinations regarding their interaction with other speakers and with the room itself.

Now granted, it would eliminate, OK perhaps I am too optimistic!, or at least minimize (hey, a fellow can dream can't he!) the emotional speculation based upon cone diameter and all sorts of other minimally significant parameters and deal with some real and meaningful specs.

How about it? Rather then base the endless discussion of "which speaker is better" based too often on one speaker you have heard, and one you have pehaps seen a picture of, why don't we seek to obtain real measured parameters?

Then we can have an informed discussion!

If only cabinet dimensions and cone diameter and the rated amplifier power could tell the story!

So why not start calling the manufacturers and politely 'demand' the plots? They have them! Why don't they publish them!?

Or, if you are really adventureous, get a group together and arrange with a dealer to audition a group of speakers and bring in someone with a TEF and measure the different speakers. You will then have the REAL fingerprint of each speaker (and yes! You can easily get measurements of the speakers independent of their room interaction!). And yes, these do correlate to subjective listening, IF you know how to interpret them! Besides, if you like, you can also shoot the room and quantify the room interaction that effects listening in the form of polars and combfilters, and the result frequency at a particular listening position! With measurements of both the speakers themselves and those of their interaction in the room where you listened to them, correlations can easily be made!

Just a thought!

[dragonfyr]

"the dual sub approach gives you some placement options to battle the room's acoustics"

Not really, but you do create a situation requiring You to battle with the room that is at least partially avoided by using just one! One is preferable to many in the acoustics realm as You minimize the interaction of the various signals.Close packing reduces, but still results in modified polars (increased lobing with the nulls constituting 180 degree out of phase cancellation) and the concommittant frequency domain comb filtering, not to mention the interesting effects upon room modes, etc.

[michael hurd]

Dragonfyr: so what are your thoughts on the subject at hand, rather than going off on a tangent? I know that you are trying to promote or stimulate thought here, but this is related how?

Are you saying that we should pay more attention to the design of the tranducer, whether the motor is underhung or overhung, how linear the suspension is, etc? Well then, I'll take a 5.25" woofer, like what bose uses in their accoustimess bass module, with gargantuan stroke, maybe that'll keep up with dual 15"s?? Regardless, more cone area is better for a subwoofer, except when you are talking about horn loading.

[dragonfyr]

I am playing the devil's advocate...

And despite lots of information, I have yet to see a comparison of apples to apples here between the two units! But lots of emotional assumptions!

I too would LOVE to have an accurate comparison of these (as I have been curious about the Titanic for some time) and many other subs and speakers, but we have yet to come up with much that can serve as a fair basis of comparison! Cabinet dimensions, cone diameter and amplifier wattage do not a valid comparison make!

OK, you're free to resume the discussion!

[dragonfyr]

Short of the Velodyne HGS18 ir DD18, I prefer the SVS Ultra.

I have not encountered another commercial sub that exhibits the combination of low frequency extension, uniform response and substantial gain across the bandpass without going to the Velodyne servo units.

And if you are desiring additional gain you are substantially better off going with one high gain unit then two summed units, due to the substantial acoustical problems introduced at the low frequencies.

I don't have real specs for the Titanic. ... Just the assorting interesting pieces that don't tell me much about the actual performance. And as I have mentioned!, I would LOVE to know more about it as I have been intrigued by its potential!

Therefore I can't properly evaluate it, But two of them covering the same frequencies in order to increase gain in the bandpass will cause more problems then they will solve.

[michael hurd]

I know that parts express has Dumax test reports on the DVC series 12" and 15" subwoofer drivers. Maybe they will be kind enough to generate and provide them for the Titanic subwoofer drivers.

I know you own an Svs Cs-ultra, how about you show us some info on the raw driver, maybe even generate some yourself.

[michael hurd]

We have covered comb filtering effects, at the relatively long wavelengths we are dealing with ( in the subwoofer realm ), comb filtering is not a problem, in MOST applications.

What other problems are you referring to?

[michael hurd]

I have e-mailed parts express with the request for a DUMAX test report on the Dayton Titanic 15" MKIII ( 295-420 ). Below is the copy I sent to them via their e-mail service.

"Hello, I was wondering if you have DUMAX test reports for the Titanic model 15" subwoofer driver, ( 295-420 ) and also if you could provide that data to me."

Vance Dickason had a hand in the design of the system ( cabinet and amp ), so I feel that there is a little more than an average dude slapping a woofer in a box and connecting it to an amplifier.

[DrWho]

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On 4/20/2005 3:44:12 PM dragonfyr wrote:

"the dual sub approach gives you some placement options to battle the room's acoustics"

Not really, but you do create a situation requiring You to battle with the room that is at least partially avoided by using just one! One is preferable to many in the acoustics realm as You minimize the interaction of the various signals.Close packing reduces, but still results in modified polars (increased lobing with the nulls constituting 180 degree out of phase cancellation) and the concommittant frequency domain comb filtering, not to mention the interesting effects upon room modes, etc.

----------------

http://www.harman.com/wp/index.jsp?articleId=1003

For the record, I've never heard of one single situation when one subwoofer was ever considered better than two (when all were of the same quality). If you can think of one, then I want to hear the difference for myself.

If having two subwoofers is a bad thing, then that implies that no speaker design should ever implement two woofers playing the same material...I guess that gets rid of the entire reference line, which I might add happens to sound very nice (they certainly aren't doing any fancy bessel arrays either). And then forget ever adding a subwoofer, because that too will introduce a new polar response as well as comb-filtering and new effects on the room modes.

Sidenote: when listening in stereo, comb filtering is one of the spatial tools our ears use for percieving a sounds location. In a room with perfect acoustics, it would be ideal to have just one monopole speaker on each side capable of 1-30,000 Hz. Of course that's not posssible so we end up building 2,3, and 4 way speakers. Adding a subwoofer to each side however just converts our mains into a 3,4, or 5 way design to give us the 20Hz-20kHz response. So in an ideal realistic world, having two subwoofers is actually better than one. Comb-filtering is also due to the physical location between two drivers playing the same material. As long as the two drivers are within 1/4 wavelength from each other, then you won't have any audible levels of comb-filtering.

The advantages of lower distortion, more SPL, or lower extension far outweigh the relatively minor effects of changing the polar response, or introducing comb filetering. If we can increase SPL and low end extension, while reducing distortion and not change the polar response (assuming the original polar response is what we want) and introducing harmful comb filering, then of course that is ideal, but it doesn't negate the first set of advantages.

For the situation at hand, I would put money down that two subwoofers (whether it be two titanics or two ultras), will sound better than the one. Yes, it takes a bit more work to dial in two subs, but it's worth the effort.

[BobbyT]

Thanks for all of the great responses. As usual a lot of good information. Looks like the Titanic is the crowd favorite so far. Which is what I'm leaning towords since I have good expeience with Dayton and none with SVS. Although SVS has a great reputation. Right now, aside from assembling a kit, diy is not an option.

[michael hurd]

Hello,

we do have this report available on our website but I have also included a copy for you as a PDF attachment. If you need anythign else please let me know.

-----Original message-----

From:

Date: Wed, 20 Apr 2005 17:22:29 -0400

To: tech@partsexpress.com

Subject: Technical Support

I thought that I would share this: I have received the Dumax report on the Titanic 15". I have e-mailed techsupport@svsubwoofers to get the Dumax report on the TV-12 driver that they use in the Cs-ultra.

295-420dumax.pdf

[michael hurd]

From : SVS - Tom V

Sent : April 21, 2005 3:54:59 PM

To :

CC :

Subject : RE: TV-12 subwoofer driver

/ / / Inbox

Hi Mike,

Im sorry but all of that information is proprietary. We do not sell any of our drivers for *DIY* applications.

Tom V.

SVS

[michael hurd]

Well looks like unless someone here wants to rip out their Ultra driver, and send it somewhere where it can be Dumax'ed, we still can't compare it to anything.

Dragonfyr: are you interested? We are all here to learn, so I would like to ask you if you would be willing to do this, in the interest of everyone here.

[Frzninvt]

Gotta say something about Mike he sure responds with the facts and data! No BSing. Hell of job Mike!

[michael hurd]

Maybe we can all chip in a couple of bucks, Dumax testing is available at DLC design, in Wixom, Michigan. Testing of a drive unit will cost $ 100, and will generate a plot of the motor strength and suspension characteristics.

http://www.dlcdesignaudio.com/

[dragonfyr]

1) I am not quite sure what this testing would afford one, as it primarily determines the maximum excursion, which, along with the Thiele/Small parameters simply aids in determining which order alignment would be optimal for enclosure design....

As we are dealing with a 'finished' design, I think this information would be moot.

What would be useful is the total system response measured in more complete and useful terms other then the max spl and wattage listed on the parts express site. SVS does provide a reasonable (but still incomplete) spl vs. frequency response curve for 2 tunings on their website.

2) Additionally, combining subwoofers is not as simple as some here suggest. Simply placing them next to each other does not necessarily result in some magic coupling without aberrations.

Additionally, attempting to array down firing boxes presents another interesting issue with arraying (as that is what combining multiple boxes to reproduce the same spectrum is), and that is to avoid narrowing of the horizontal field, they must be stacked vertically, with driver spacing minimized. With a down-firing woofer this additionally has the effect of truncating the plane onto which they fire rather like taking a speaker from a corner placement to the center of the room, and thus effectively increasing the sphere radians/volume and most likely decreasing efficiency, but I have not personally tried this with a down firing sub so.... But I guess you could simply turn them on their side and make them direct radiating, thus allowing for them to be more tightly packed. I am sure this is stated awkwardly...

I am attaching an application note addressing the arraying of LF units. I realize that a few may jump up and down regarding this, but unfortunately this area is pretty well understood, even if it is seldom practiced well! We have addressed this in large acoustic spaces rather extensively despite some rather abysmally applied examples in large scale sound reinforcement.

I will let the attachment speak for itself, but the application suggestions imply much more then they explicitly state!

One of the most difficult assumptions to overcome has been the idea that if someone wants the same response with additional gain, all they have to do is add an additional identical unit. Nothing could be further from the truth!

3) Oh, and one note that I simply can't allow to stand.

"when listening in stereo, comb filtering is one of the spatial tools our ears use for perceiving a sounds location."

Comb filtering is the result of two or more apparent non-minimum phase sources that are superimposed! The net displacement of the medium at any point in space or time, is simply the sum of the individual wave displacements. In its most extreme form it is effectively active noise cancellation (to misuse the term), whereby the 180degree out of phase signals completely cancel, and in more common complex forms, this includes a mixture of phase and amplitude that sum, resulting in a modification of the individual component waveforms into a resultant waveform ...superposition. And what we commonly refer to as comb filtering are the nulls resulting from signals that are 180 degrees out of phase.

Localization involves the processing of both the propagation delay and differences in the amplitude spectrum between the left and right ear of the direct (and near field reflected signals off outer ear, shoulders, etc.) signal within the limits of resolution imposed by the Haas effect. The existence of comb filtering in an acoustical environment does not add to the ability to localize points of origin!

And if only stereo were a truly ideal modeling environment! Heck, of only 1^99999999.1 were an ideal modeling environment!!!!!

4) And here are two of quite a few good modeling sites for playing with superposition. Have fun!

http://www.phy.ntnu.edu.tw/java/waveSuperposition/waveSuperposition.html

http://www.kettering.edu/~drussell/Demos/superposition/superposition.html

But in any regards, I hope you enjoy whichever unit you choose!

I don't think that you can go to far 'wrong' with either unit!

Enjoy!

LowFreqDirectivity.pdf