Yet another sub selection question.

[NoMSG]

You guys are probably getting tired of my wishiwashiness. I thought I narrowed it down to the SVS PB10-ISD after comparing it to others in the same price range, but now...

After reading a few more threads, I kept coming across the Titanic MKIII 12" kit. Sounds like buidling it is a no-brainer for someone who can use tools. The price difference between these two is relatively minor, with $536 shipped for the Titanic and $480 shipped for the PB10. OK, now which one to get?

I'll be using the sub for mostly HT, paired with Energy C-8s up front, an Energy AC300 center, and Energy 2.2 rears. The room is medium/large with 8' ceiling.

Bottom line, it seems like the PB10 goes lower (to under 20 Hz), and probably flatter while doing it. The Titanic goes to about 25 Hz, but can go louder. The difference in size and appearance quality is not an issue for me. The lack of a crossover setting on the PB10 is not an issue.

I understand that the Titanic is a sealed unit, and that the SVS is not. But I'm not sure how this translates into real world performance between the two subs at issue.

A review I read measured the SPL of the PB10 at between 104 and 107 during some sections of bass-heavy movies in a mid-sized room. The Parts Express website listed in-room SPL of 110 dB for the Titanic (the environment was not specified) My first question is, what do these numbers mean in a real world envirnoment for my room for HT?

For my medium/large room, it seems like the PB10 would be more accurate and would go lower if I kept it at moderate levels. But if I listened at high volume levels, the Titanic would have the edge. I'm drawing this conclusion based only on the numbers.

Because of practical considerations, the sub is going to be placed directly behind the seating area, against one wall and 2 to 10 feet from the corner. With the sub so close to the listener (about 3 to 6 feet away from the ears), would I really benefit from the Titanic 12", even in a medium/large room, over the PB10?

Is there any other factor or issue I should consider?

Thanks for all your patience and all your prior responses. It seems like the more answers I get, the more questions I have. This is what happens when youhave more time than money.

[kexodusc]

You guys are probably getting tired of my wishiwashiness. I thought I narrowed it down to the SVS PB10-ISD after comparing it to others in the same price range, but now...

After reading a few more threads, I kept coming across the Titanic MKIII 12" kit. Sounds like buidling it is a no-brainer for someone who can use tools. The price difference between these two is relatively minor, with $536 shipped for the Titanic and $480 shipped for the PB10. OK, now which one to get?

I'll be using the sub for mostly HT, paired with Energy C-8s up front, an Energy AC300 center, and Energy 2.2 rears. The room is medium/large with 8' ceiling.

It's hard to make a recommendation without knowing your specific tastes, but you ask some good questions here, which might narrow it down for you


Bottom line, it seems like the PB10 goes lower (to under 20 Hz), and probably flatter while doing it. The Titanic goes to about 25 Hz, but can go louder. The difference in size and appearance quality is not an issue for me. The lack of a crossover setting on the PB10 is not an issue.
Errrr...not exactly there's still response from the Titanic kit below 25 Hz...down to 20 or so, the 25 Hz number you're reading reflects the SPL value that was given with it...the frequency response drops of gradually below that, but it's there.
More important is the way these subs will perform in your room. I wouldn't hold my breath that either actually get you down to 20 Hz at a great level, regardless of what the factory measurments say.



I understand that the Titanic is a sealed unit, and that the SVS is not. But I'm not sure how this translates into real world performance between the two subs at issue.
You feel much more impact from a sealed subwoofer design. More punch. Think of it like a bass drum kick generating the frequency versus blowing into an empty coke-bottle. The frequency might be the same, but the sounds are actually quite different.
Generally, to the most descriminating ears, it is accepted that sealed subs present a tighter, more defined, and accurate sound which makes them very well suited for music. Ported subs are blessed with higher output and lower response, but sacrifice the sound quality to produce this, all things equal. Because the higher output and lower extension is usually achieved at a cost lower than that of sealed sub with the same capabilities, they are often attractive options for home theater use.

This isn't to say that either design doesn't work well for use with both music and home theater, because they do. Just that there are respective strengths.



A review I read measured the SPL of the PB10 at between 104 and 107 during some sections of bass-heavy movies in a mid-sized room. The Parts Express website listed in-room SPL of 110 dB for the Titanic (the environment was not specified) My first question is, what do these numbers mean in a real world envirnoment for my room for HT?
The Parts Express numbers are done in their anechoic room (which I understand isn't perfect), you can expect better results in an actual listening room, mid size, large or whatever.. All this means is that the 12" Titanic will produce the bass output of anywhere from 2 to 3 of the PB10 units. More power, more swept volume air. It's a stronger subwoofer.



For my medium/large room, it seems like the PB10 would be more accurate and would go lower if I kept it at moderate levels. But if I listened at high volume levels, the Titanic would have the edge. I'm drawing this conclusion based only on the numbers.
This is the problem with trying to buy speakers/subwoofers based on published specs alone...you have to actually listen. Unfortunately for you, the chances of this ever happening are slim to none since both aren't carried in local stores.
The Titanic will produce a more refined and accurate sound, of this I have little doubt. Sealed subwoofers of this quality would generally run you quite a bit more money if bought from a commercial source. Not to take anything away from the SVS, it too uses high quality components, especially the TC Sounds woofer, but that 12" Dayton woofer and 500 watt plate amp are a steal at this price. I built one for my folks last year and it sold me on Dayton's drivers. The 12" MKIII easily outperformed my Paradigm PW-2200, which is a better subwoofer than the PB10 (though probably not as good a value).

The Titanic will give you a very accurate, punchy, clean and defined sound, I would argue you'd be looking at $1000-$1500 subwoofers to match its performance (but it isn't terribly pretty to look at). The PB10 however <i>might</i> give you 1 or 2 Hz more bottom end extension. My old Wharfedales had a lower bass response than my Paradigm Studio 40's, but the 40's were a much nicer sounding speaker. Lesson: bass extension isn't everything, it goes back to what I said about trying to buy on specs alone.

Since you intend to use this for mostly home theater purposes, the PB10 might very well be a better value for you. It's pre-assembled, looks nice, and is quite an impressive unit for the money. If you're asking which subwoofer sounds better, I have to beieve the Titanic will. Whether it's worth the exra money for your applications is up to you to decide.



Because of practical considerations, the sub is going to be placed directly behind the seating area, against one wall and 2 to 10 feet from the corner. With the sub so close to the listener (about 3 to 6 feet away from the ears), would I really benefit from the Titanic 12", even in a medium/large room, over the PB10?

Is there any other factor or issue I should consider?

Actually the ported sub being close to the wall and corners will probably cause some added difficulties in achieving a flat in room response...I would think a sealed unit would be a bit better here, but depending how much flexibility you have in placing the unit out a few inches from the wall, it might not matter.



Thanks for all your patience and all your prior responses. It seems like the more answers I get, the more questions I have. This is what happens when youhave more time than money.

You've already learned a lesson many of us didn't until we'd already dumped hundreds or thousands into our systems...it pays to ask questions BEFORE buying!!!

Good luck, let us know what you decide.

[kexodusc]

I would just like to add that a quick alternative to the 12" Titanic MKIII that is cheaper and I believe still a superior unit to the SVS is the Adire Rava....I've not heard this unit personally, but on the surface it looks like an excellent subwoofer...I'm considering building a subwoofer based on the 15" version of its woofer. The Rava might be just what you're looking for at $399.

http://www.adireaudio.com/TextPages/RavaPageFrameText.htm

You might try flagging down Woochifer here, a forum regular who has more experience with this unit. He's thrilled with his and I'm sure he'd be happy to answer any questions.

[bargainseeker]

I'll just add one comment. You shouldn't judge the sound quality of the SVS PB10 based on the sound quality of other ported subwoofers you have heard. To my ears, the PB10 is the tightest sounding, most "musical" ported sub I have ever heard that is available at a reasonable cost. It beats many sealed subs that I have heard in this regard. One caveat - if the PB10 is placed in a smallish room, room gain can make the PB10 sound bloated due to overemphasis of the lowest bass frequencies. Just one reason I recommended that NoMSG get a BFD with his subwoofer purchase.

[kexodusc]

Bargainseeker is right about the BFD...I'd recommend one for any subwoofer. As bargainseeker mentioned, room gain will effect not just the SVS units, but any subwoofer to varying degrees.

And I certainly wouldn't compare the PB10 to most $400 ported units, then again the Titanic MKIII is in a league of it's own compared to most sealed subs as well. Even the wold's finest ported subwoofers are subject to higher EBP, faster cutoff below resonance and compromised transient response around the port and cabinet tunings - something designers all knowingly accept to acheive the desired output and extension. I've only heard the PB-12 but it was obvious to me that this sub wasn't the final word in bass definition. I suspect these cabinets are tuned very precisely with the TC Sounds woofer to acheive the best transient response possible, though SVS themselves seem to agree that the PB-12 and PB-10 could be improved upon by reducing the extension...they have a few sub models that do just this and are recommended for music apps specifically.

Pick what's more important to you and be happy.

[bargainseeker]

I've only heard the PB-12 but it was obvious to me that this sub wasn't the final word in bass definition. I suspect these cabinets are tuned very precisely with the TC Sounds woofer to acheive the best transient response possible, though SVS themselves seem to agree that the PB-12 and PB-10 could be improved upon by reducing the extension...they have a few sub models that do just this and are recommended for music apps specifically.Since single driver box (PB) subwoofers based on the Plus and Ultra woofers are not yet available from SVS, I assume that by PB-12 you mean the PB12-ISD? If so, I would say that the sound of this subwoofer bears little resemblance to that of the PB10. The PB12-ISD uses a woofer that is not made by TC-Sounds and that does not feature the same technology as the woofer in the PB10.

[kexodusc]

I'm not oblivious to the fact that the PB-10 is probably the standard in the $400 subwoofer category. Nonetheless, SVS would have me believe the 12" is the better subwoofer...I just took a look on their web page...seems their's a have dozen or so PB-12's, I'm not sure which one I listened to but I find it hard to believe that SVS, a very reputable sub vendor, would charge people more for an inferior subwoofer. The cult like following they have would be enraged.
Maybe they do, either way what I've said above is still very much relevant and accurate.

It's hard to really compare a 12" sealed to a 10" ported though. The a 10" ported design is disadvantaged from the start. A 10" sealed unit would not be good for HT at all, and is often not bothered with, if comparing to a 10" sealed unit like the 10" Titanic MKIII, I'd go with the SVS no question..

I think, in a mid sized room, if it was me and I new music wasn't a priority, I'd save the $60 bucks or so and put that towards a BFD. If a good mix of music and HT was in the mix, alot of output was desired, or simply the best sounding unit, the Titanic would get my vote. Be careful though, you can extra $60 yourself into the poor house buying audio gear.

[Woochifer]

You're talking about two very different designs here. The SVS sub is ported and they likely balanced the port opening and the box volume for maximum bass extension (the HSU VTF-2 has a switchable amp that changes the EQ profile between maximum output versus maximum bass extension; all do is flip the switch and plug one of the ports for maximum extension). I would also suspect that they incorporated some kind of an EQ circuit to flatten out the frequency response deviations that occur when you extend the bass extension in a ported box.

Generally, ported subs are more efficient, and can play louder. They can also have a more steady frequency response down to the port frequency. But, ported subs are also trickier to design and build right, and their more sudden dropoff at the low end subjectively might not sound as "musical" as something that drops off more gradually. Also, if the ported sub does not have a rumble filter, then the driver can "unload" and move uncontrollably below the tuned port frequency because the port can no longer dampen the cone movement at that point.

The Titanic kit is a sealed design, which brings its own set of advantages and disadvantages. The main advantage of a sealed sub is that it generally has quicker transient response, and the more gradual rolloff at the low end might subjectively sound more "musical". The disadvantages of sealed subs are that they are less efficient, the rolloff at the low end begins sooner than with equivalent ported subs, and their distortion increases as the sound gets closer to the lower limit.

If you have a small to medium sized room, the room creates a cabin gain effect that boosts the lower frequencies. Given that that this room gain and the low end dropoff on a sealed sub occur at approximately the same rate, this makes sealed subs very well suited to smaller rooms.

If you consider the Titanic kit, then you should also look into the Adire Audio Rava and Acoustic Visions MRS-10 as well. The Rava sells for $400 and like the Titanic, it's a 12" sealed design built around a mid-Q alignment. Acoustic Visions' MRS-10 is a 10" sealed sub that its designers made specifically to take advantage of the cabin gain in smaller rooms.

If you do opt for the SVS and you have a smaller room, definitely grab a Behringer Feedback Destroyer to EQ your subwoofer. The EQ is one tool that you can use to minimize the detrimental effect of room modes. This effect occurs when the reflected low frequency waves interact with one another and create cancellations and peaks. This results in bass that can alternately sound horribly boomy or anemic.

The first step is to properly place the subwoofer in a location with the least pronounced acoustical problems. The second step is to measure your in-room response with a SPL meter and test tones to identify any problems at specific frequencies. Then you use corner bass traps and/or a parametric EQ to correct these problems. I have an Adire Rava and even in a 13x18 room, it sounded boomy and overly aggressive out of the box. Using a BFD, I corrected the three biggest problem areas, and it made a huge improvement in how the bass sounds overall.

[NoMSG]

Kexodusc, Bargainseeker, Woochifer, and everyone else, thank you for your time and your well thought out responses--both on this thread and the earlier ones I posted.

Although I'm comparing two very different designs, in the end what matters is how it sounds for the application I have. I seem to have all the information I need with respect to the question posted. The only "problem" now is that I'm looking into the Adire Rava as well.

I understand and do not dispute that a ported design would be more difficult to properly position in a smaller room or that it would have a sharper dropoff once the lower intended frequencies are reached. What did surprise me is your estimate, Kexodusc, that it would take 2 or 3 PB-10s to achieve the "bass output" of the Titanic 12". This may be an issue for me because my "moderate" listening levels is slightly lower than THX movie theater levels.

With respect to the price difference, it's not because I won't notice $60. It's just that I have found that it can be more expensive to settle, if I'm likely to upgrade later. It sounds like I may be satisfied with the PB-10, but it seems highly unlikely that I'll "need" anything beyond the Titanic 12".

Now I just need to get up to speed on how to put a veneer on that homely Titanic.

[kexodusc]

...that it would take 2 or 3 PB-10s to achieve the "bass output" of the Titanic 12". This may be an issue for me because my "moderate" listening levels is slightly lower than THX movie theater levels.

I may have missed it but I don't see your room dimensions posted here. That being said, unless your room is positively huge like mine (20 X 22 X 8) I don't think you're going to have a problem with any of these subs going loud. I might wonder about sound quality at these volumes though.
If the PB-10 indeed can reach peak outputs at 104dB to 107dB with room gain, this is pretty loud. I would question how flat is the response at these SPL's...the Titanic is reasonably flat to 25Hz at 110 dB. This is exceptionally loud. Headroom is always nice, but if you really don't need it, then you probably shouldn't pay for it. But, the bottom line is a high xmax 12" woofer mated to a 500 watt amp is going to push more cubic inches or litres of air than a 10" ported sub with 300 watts. It might be nice to know that your woofer won't bottom out or your amp clip at high levels.



With respect to the price difference, it's not because I won't notice $60. It's just that I have found that it can be more expensive to settle, if I'm likely to upgrade later. It sounds like I may be satisfied with the PB-10, but it seems highly unlikely that I'll "need" anything beyond the Titanic 12".

Now I just need to get up to speed on how to put a veneer on that homely Titanic.
There in lies the beaty of the Rava. I believe you get your choice of oak or black veneered finish. Pretty nice deal. The cabinets look like Woodstyle MDF cabinets...very solid construction.
If you decide on a Titanic, veneering a cubic inclose is actually very, very easy, and not that expensive if so desired.
It's the staining and especially the varnishing that requires a bit of effort. The only trick will be the woofer cutout hole. You'll need a router and trim bit. Or you can do it by hand with a very sharp utility knife and a lot of patience and care. Or, leave the front black with the grill on and nobody will ever know. If you're somewhat new to this I'd recommend iron on veneer...it's easy to remove if you don't like a piece and since the cabinet is cubic, you won't have any problems wrapping or splitting, I don't think. Also, practice on a fair size piece of scrap veneer to get the colour and gloss that you want.
My first attempt at a dark rosenut/cherry color ended up looking a we bit too orange at first, and I had to reveneer a speaker...learned that lesson the hard way.

It's not so much that the cabinet is ugly...it's just a bit bland.

[NoMSG]

unless your room is positively huge like mine (20 X 22 X 8) I don't think you're going to have a problem with any of these subs going loud. I might wonder about sound quality at these volumes though.
If the PB-10 indeed can reach peak outputs at 104dB to 107dB with room gain, this is pretty loud. I would question how flat is the response at these SPL's...the Titanic is reasonably flat to 25Hz at 110 dB. This is exceptionally loud.

My room is 13 x 20 feet. However along one of the 20-foot walls is a 6-foot wide archway that connects it to the adjacent room (which is about the same size, as well).

The independent review of the PB-10 reads:


In order to determine the quasi-anechoic frequency response, the PB10-ISD was tested outdoors, away from any reflective structures, and measured using ground plane techniques. Measurements were conducted with the microphone facing the woofer and vent, at 2 meters from the depth centerline of the subwoofer enclosure, and the phase control set to 0 degrees.

....

The PB10-ISD frequency response measured an almost unbelievable ± 1 dB from 19 Hz - 150 Hz. The sharp roll-off below 19 Hz indicates the presence of a steep infrasonic high-pass filter to protect the woofer from over-excursion below the tuning point. With respect to dynamic compression, the curve stayed linear up to 104 dB across the entire operating bandwidth, at which point about 1 dB of compression was noted at around 20 Hz.
....
Ground Plane Total Harmonic Distortion (THD) Measurements
Harmonic distortion occurs when harmonics (multiples) of the fundamental signal are produced due to non-linear behavior of the electrical, magnetic, or mechanical aspects of the driver. A subwoofer with low THD will sound clean and distinct, especially at the deepest frequencies where distortion harmonics are easiest to detect.

Measurements were conducted at 2 meters from the centerline of the subwoofer enclosure. To calculate the 1 meter test values, add 6 dB to the 2 meter reading. THD was limited to 10% unless otherwise noted. With the exception of 22 Hz, test frequency spacing was at 1/3 octave intervals.

Audio reviewer Tom Nousaine calculates bandwidth linearity by dividing the average SPL by the maximum SPL and expressing the results as a percentage. A score of 100% means the subwoofer exhibits perfect output linearity across the given bandwidth.

SVS PB10-ISD 10% THD Values (Ground Plane 2 Meters):

20 Hz: 93.9 dB (8.0 % - amplifier limited)
22 Hz: 96.9 dB (2.7 % - amplifier limited)
25 Hz: 102.2 dB
32 Hz: 104.1 dB
40 Hz: 105.8 dB
50 Hz: 106.7 dB
63 Hz: 105.7 dB
80 Hz: 104.0 dB

20-80 Hz: Average 102.4 dB; Bandwidth Linearity 96%
22-80 Hz: Average 103.6 dB; Bandwidth Linearity 97%
25-80 Hz: Average 104.8 dB; Bandwidth Linearity 98%

These distortion and bandwidth linearity values are simply outstanding. Note the amplifier limited the output at 20 Hz - 22 Hz, and the distortion at 22 Hz was only 2.7%!



If I am reading the numbers right, it seems like the PB-10 can go loud, low, and flat. But then again, the numbers may not tell the complete story. What do you think? Does it sound like the PB-10 might well be enough?

[kexodusc]

In a 13 X 20 room I would think the PB-10 would be loud enough. These numbers are very good for a commercial 10 inch subwoofer at this price point. I can see by the figures that the system is tuned somewhere around 50 Hz. What I'd expect from a 10" subwoofer.
But numbers do NOT tell the whole story. +/- linear response is nice to have, but it does not begin to describe the transient responses or the tightness, impact and other traits of a subwoofer.
Paradigm has the Titans, about $270, that measure +/- 2 dB from 60Hz - 20kHz, they also have the Studio 40's which measure about the same...on and off axis...yet there's a reason the Studio 40's cost 4 times as much...they're just a far superior speaker.
This goes back to what I said about the problems judging speakers on specs alone...I see alot of internet companies have started up in recent years and boast fantastic numbers. My Axiom M3Ti's got more praise than any other speaker I know, and my VTF-2 was highly praised, and while I feel both are good, they aren't much, if at all better than many brick and mortar store offerings of similar price...Best Buy speakers not included.
You wouldn't go watch a movie because the poster says it's the most thrilling sci-fi thriller of our time, take everything with a grain of salt. Even what I say.

Subwoofers have come further in performance improvements, and affordability over the last few years than any other part of the audio chain, IMO. I have little doubt the PB-10 is a great subwoofer at this price, and does a good job, I just don't see anything here that leads me to believe it comes close to the 12" Titanic or Rava subs.

There is a fundamental sound characteristic below the tuning point that is just different between sealed and ported subs, and an overall tightness added by the lower compliance. I am very sure your dollars would go further with one of the other kits, but, it's your money. You'll have to decide if you want that extra Hz or two, or the extra output and sound quality...there isn't a right or wrong answer, just what you think is better.

[Tom V.]

Hi all,

>>>In a 13 X 20 room I would think the PB-10 would be loud enough. These numbers are very good for a commercial 10 inch subwoofer at this price point. I can see by the figures that the system is tuned somewhere around 50 Hz. What I'd expect from a 10" subwoofer.<<<


If you are refering to the resonant frequency of the enclosure(the *tuning* point so to speak), the PB10 is actually <20hz. That, along with a 300w FTC certified amp platform AND a driver with 2-3x the clean stroke of like priced competition is what allow the SVS PB10 to perform so well. We aren't trying to sell you magic fairy dust...just real watts, a well designed enclosure, and a lot of stroke on the driver..:)

Tom V.
SVS

[kexodusc]

Tom V, are you saying the Fb of the PB-10 is below 20 Hz?
Can you provide any T/S parameters?

[This Guy]

Yea I was actually very interested in what the T/S parameters of this driver is, just for comparing reasons.

[Woochifer]

There in lies the beaty of the Rava. I believe you get your choice of oak or black veneered finish. Pretty nice deal. The cabinets look like Woodstyle MDF cabinets...very solid construction.
If you decide on a Titanic, veneering a cubic inclose is actually very, very easy, and not that expensive if so desired.

You're right about the cabinet on the Rava. Surprisingly decent quality at its price point, especially considering that the cost for the amp and driver alone will set you back $305. Basically, you're paying $95 for a prefinished cabinet and assembly, and I've seen vendors charge more than that just for a preassembled cabinet with no finish. If you're planning a DIY project around the Shiva driver with a comparable 250 watt amp, then the only reasons I see to go build it yourself would be if you have a specific type of performance that you're aiming for, or just prefer the challenge of building it yourself.

The cabinet itself is made out of HDF with no internal bracing. The veneer is a well done oak finish, and they use what looks like hand brush-applied gloss back paint on the front and back of the unit. That type of oak look in general seems like a relic out of the 80s, especially compared to some of the slicker looking piano black and gloss cherry and rosewood finishes that other manufacturers like Rocket. But, for $400 that's really getting nitpicky. I have not seen the black finish, but if the black paint that they apply to the front and back of the unit is any indication (both sides are out of view because the front is covered by a grille), I would opt for the oak finish. Compared to other subs, the Rava looks more like a glorified DIY project, but then again, that's pretty much what it is since Adire does not mass produce them.

[Peter Marcks]

Dear NoMSG,

I suggest purchasing both products and comparing them in your own home. Shipping is free on the Titanic MKIII kit, so the potential costs are small anyway.

Best of luck to you

Sincerely,

Peter Marcks
Hsu Research

[kexodusc]

Good lord, we've got SVS and Hsu reps visiting the forums...whose next? Dr. Amar Bose?

I must say, it is refreshing to see a company rep offer advice WITHOUT shilling his own wares or handing out brochures....

I like the idea of purchasing both though...PE has a 45 day money-back guarantee on their sub kits.

Mr. Marcks...what's new on the horizon from Hsu Research?

[Tom V.]

>>>Tom V, are you saying the Fb of the PB-10 is below 20 Hz?<<<

Yes, the resonant frequency(tuning point) of the enclosure is under 20hz. That is part of the reason why the PB10 will provide strong bass down to the 16-18hz range in almost all listening environments.

>>>Can you provide any T/S parameters?<<<

I'm sorry but we don't disclose any info like that on our drivers. I will say it has almost 2"(peak to peak) of clean excursion. You can get away with *modest* excursion drivers and still do fine from say 30-35hz and up. But REAL bass...bass in the first octave(16-32hz) takes a lot of excursion..:)

Tom V.
SVS

[kexodusc]

The cabinet itself is made out of HDF with no internal bracing.

Actually, according to Adire, the cabinets are HDPB, which is just about equal to MDF, though it tends to absorb a wee bit more energy. Still more than adequate for sub that size...some would argue HDPB adds certain springiness to the sound that is desired. Most literature I've read recommends avoiding HDF for speaker cabinets as it tends to overdampen the cabinet, killing transient response.. Maybe HDF could be used for subwoofers though, not sure. Some studies have been done comparing 3/4" MDF to 1" MDF, with the results in favor of the thinner board for speakers but the thicker board for subwoofers (David Weems, Vance Dickason, etc). I've also read that plywoods (especially Birch) tend to add a bit of this springy flavor to the sound too. Some call it coloration, some call it a natural decay... Peter Qvortrup of Audio Note certainly echoes the benefits of Birch ply (don't tell RGA I said this). I think there's some merit to it, but it's usually more expensive and hard to shape vs. MDF.

I've only worked with HDF once...hard as hell on router bits and extremely heavy.

[Peter Marcks]

Dear kexodusc,

Thank you for the kind words!

We are working on some brand new technology right now, to be featured on new VTF HO subs. If you go to our website and search for VTF-3HO, you can find some good info coming from the 2005 CES. One of the things that we are excited about is the advancement in variable tuning technology. With a turbocharger accessory, one will be able to lower the tune without compromising port flow area, all without actually adding to the box length! This fits in well with Dr. Hsu's goal of constantly trying to provide more bass per floorspace occupied. We hope to have more details available in the next few months. All I can say is that only a true audio genius such as Dr. Hsu could have even dreamed of such a design. We hope consumers will be very happy with the look and feel of the new designs.

Sincerely,

Peter Marcks
Hsu Research

[RGA]

Actually, according to Adire, the cabinets are HDPB, which is just about equal to MDF, though it tends to absorb a wee bit more energy. Still more than adequate for sub that size...some would argue HDPB adds certain springiness to the sound that is desired. Most literature I've read recommends avoiding HDF for speaker cabinets as it tends to overdampen the cabinet, killing transient response.. Maybe HDF could be used for subwoofers though, not sure. Some studies have been done comparing 3/4" MDF to 1" MDF, with the results in favor of the thinner board for speakers but the thicker board for subwoofers (David Weems, Vance Dickason, etc). I've also read that plywoods (especially Birch) tend to add a bit of this springy flavor to the sound too. Some call it coloration, some call it a natural decay... Peter Qvortrup of Audio Note certainly echoes the benefits of Birch ply (don't tell RGA I said this). I think there's some merit to it, but it's usually more expensive and hard to shape vs. MDF.

I've only worked with HDF once...hard as hell on router bits and extremely heavy.

Sorry I actually was bored and decided to read a sub thread :D Peter has spent 4 years working on a sub but until it is matched as closely as their drivers are now --- no audible seamlessness is tolerated and neither is trying to fix it with an EQ - the bass cannot exhibit the typical one note bass I've heard from most subs --- I believe he has been talking to dedicated sub makers on a co-production --- probably REL since they're close by -- they are also cosnidering starting a recording studio --- I know Peter is good freinds with a fellow at Chesky --- there was a show in NY a while ago where they pitted some big expensive systems Audio Note in one room Wilson in others etc.

The Sub he's working on is a tube powered sub based off the 845 tube - but he's anal and won't bring it out unless it matches. Since he said it is soley designed for the E it will no doubt muster under 10hz at level.

Birch is clearly better than chipboard MDF combos --- listen to the Chipboard E and the Birch E--- Peter harps on it all the time and told B&W how to make their speakers better -- but like you note -- it costs more money and time.

[kexodusc]

Birch is clearly better than chipboard MDF combos --- listen to the Chipboard E and the Birch E--- Peter harps on it all the time and told B&W how to make their speakers better -- but like you note -- it costs more money and time.

I knew you'd find this :D

I've never heard of a chipboard/MDF combo...one or the other usually.
Actually, I think the choice of material is specific to the designer's goals and takes into consideration the other components/aspects of the system. Some drivers require so much dampening that birch wouldn't be appropriate, and some vice-versa. Personally, I'm no pro or anything, but I use a handfull or two of very loose polyfill in all the speakers I've made except for 1 design which necessarily required a good fill of acousta-stuff to achieve the desired bass extension (though I suspect one could have simply increased the cabinet's volume). No foam, insulation, excessive fill needed usually.
I don't have any theory to support this, but my ears tell me dampening cabinets too much seems to cut down on some resonance, standing waves, colourations, etc, but to me it also seems to choke out some pleasant aspects...attack, decay, release of energy...hard to describe...and I'm way off topic now...