Coming soon, subjective SQ tests.

**Chrisbee** · **03-04-07, 05:09 PM**

Quote:

SteveCallas wrote:

Lol, same here. To get my flattest response, I need to close the doors to my bedroom, bathroom, and laundry area, but I have to open the door to my office room, which is an extra ~1276 cubic foot chunk of space. Oddly enough, the region that opening/shutting the doors to my office room affects is only the <20hz region.

Perhaps it is not a matter of volume but an increase in boundary spacing? Does anybody still subscribe to the idea that you need a half wavelength between boundaries to reach a clean (low distortion) low frequency?

By opening a door you extend the interboundary dimensions to better match the half wavelength of a particular frequency and perhaps benefit from an increase in room gain as a result.

The listening (or testing) position may be critical to any changes as a result of particular doors being open or closed. (Pressure nodes and antinodes may be moved bodily relative to the microphone position when doors are open or closed)

**Exocer** · **03-05-07, 10:11 PM**

Very good point Chris. My knowledge in that specific area is very limited and I would love to learn more about how the length of a room effects certain frequencies.

One thing I did forget to mention is have a 5x5x8' walk in closet with its door usually open. That, I am convinced, acts as a huge bass trap. None of the 4 subs i've had in this room exhibit any type of extremely peaky frequency response. I've run a few measurements with that walk-in closet closed and subjectively all of the subwoofers used in my room sounded better with that closet open.

P.s. - Mark, I've been a little busy lately with life matters but will certainly get around to doing the measurements.

**Exocer** · **03-06-07, 12:04 AM**

Not that this even matters but I realized today that I do indeed have a dedicated 125v, 20A outlet in my room. So, amps like the ep2500 (rated to put out over 2000watts) will not be limited by the 15a standard outlets if the upgrade does present itself down the road.

**Exocer** · **03-15-07, 10:51 PM**

Ok, well updating the graphs isn't possible. I either forgot where the measurement files are saved or never saved the actual measurement and just took a snap shot (which wouldn't suprise me).

This round-up will officially be between the Ava 15 and Tc-3000 now that my nephew found a way to sit "in" the Tumult and detach the dustcap from cone.(believe me, this infuriated me...) Probably will try and purchase paper gorilla glue to get it re-attached ASAP, (with this disadvantage i'd recommend taking the Tumult measurements as way less than gospel, apparently the driver is nowhere near new/working shape).

WillD asked me today if I'd remove all of the interior stuffing when using the TC-3000 to achieve an overall higher Q. I've given it some thought but feared possible resonances inside of the enclosure having a negative impact on sound quality without any form of interior damping. The current 1 1/2" egg-crate foam that lines the interior walls of the box at the moment will remain in the box. Unibox doesn't suggest a major impact on damping.

Anyhow, this will still remain an interesting comparo. We have two drivers with naturally low Qtc's in this alignment. One high Bl driver with low vas (Tc-3k). One "linear" designed driver with lower Bl, but what it lacks in Bl it re-gains in having a lower moving mass and a much softer suspension overall. This will still be an effective comparison between two completely different design choices that work in "smaller" boxes.

**Exocer** · **03-30-07, 04:25 PM**

Progress...

The TC-3k arrives!

Here's a picture of all three side by side. I'll let you guys decide if there are any SD differences...I definitely notice one.

Side shot of the Tummy and TC

The TC-3k is a taste of something different for me...my very first non-linear coil 15" driver.So naturally I did not know what to expect in terms of sound quality. Graphs suggest this:

While actual in-room response is in the graph below. Light green is the TC-3k, dark green the Ava 15.
No EQ.

Apparently the TC-3k isn't dropping off any sooner than the Avalanche 15 w/ 80hz crossover...Anything higher in the upper end just does not matter to me. (If anyone would like me to measure without the crossover in the loop let me know.) The two drivers measure similarly...but both measure extremely different than simulations.

I'll get into more detail as I spend more time with the driver. It still is not "broken-in" so to say.

WillD recommended I take a sweep up to 500hz. I'll do it once I get the cables to send a direct signal from my soundcard to the ep1500...Any questions?

**kramskoi** · **03-31-07, 02:43 AM**

Quote:

Exocer wrote:

Progress...

The TC-3k arrives!

Here's a picture of all three side by side. I'll let you guys decide if there are any SD differences...I definitely notice one.

Side shot of the Tummy and TC

The TC-3k is a taste of something different for me...my very first non-linear coil 15" driver.So naturally I did not know what to expect in terms of sound quality. Graphs suggest this:

While actual in-room response is in the graph below. Light green is the TC-3k, dark green the Ava 15.
No EQ.

Apparently the TC-3k isn't dropping off any sooner than the Avalanche 15 w/ 80hz crossover...Anything higher in the upper end just does not matter to me. (If anyone would like me to measure without the crossover in the loop let me know.) The two drivers measure similarly...but both measure extremely different than simulations.

I'll get into more detail as I spend more time with the driver. It still is not "broken-in" so to say.

WillD recommended I take a sweep up to 500hz. I'll do it once I get the cables to send a direct signal from my soundcard to the ep1500...Any questions?

that's why you "play the game"...the shorting ring must be helping up top...interesting observations Ex...from the standpoint of FR and THX crossover, inductance is'nt everything it seems...now flux distortion is another matter but as frequency falls, inductance rises...fact of the matter?...one must simply live with inductance issues with these high xmax, high weight (magnet) drivers...the old Tumult inductance graph is a good example of this...keep me posted on your tests Ex...good work...have fun with the new beast...martin

**WillyD** · **03-31-07, 03:49 AM**

I only wish I could be there to enjoy the new drive too!

From what I hear, it is quite the performer.

And Martin, I agree that the inductance issue isn't quite as black and white as some were making it out to be. Rob's measurements certainly don't indicate an early roll off, and he told me that it blends in well with his Natalie P's. It makes me wonder....

**SteveCallas** · **03-31-07, 11:58 AM**

I don't quite get the life and death obsession others seem to have with Le either. These are subwoofers we are talking about, meant to be crossed at 80hz, meant to handle the LOW end. I haven't seen anything from this new crop of TC drivers to come close to looking like an issue.

Exocer, touching on your Sd comment, are all 3 drivers' diameters the same? If they are, and the cone on the TC3k just looks bigger, I'm wondering if the thin surround on it doesn't negate the difference, as you include 1/3 of the surround as part of the moving surface.

**Exocer** · **03-31-07, 12:40 PM**

Quote:

SteveCallas wrote:

Exocer, touching on your Sd comment, are all 3 drivers' diameters the same? If they are, and the cone on the TC3k just looks bigger, I'm wondering if the thin surround on it doesn't negate the difference, as you include 1/3 of the surround as part of the moving surface.

Very good point.

In person, the TC-3k just appears to be the larger driver from a pure displacement standpoint. Including the 1/3rd of the Tumult's surround makes the two a bit closer, but the TC-3k would still appear to be the larger driver.

Is it a significant size difference? Absolutely not.
Do the pictures convey the size differences well? Absolutely not

I wish you guys were able to press a button and transport over just to see for yourself to draw your own conclusions.

**Exocer** · **03-31-07, 01:15 PM**

I've had some more time to spend with the TC-3k and an SPL meter in hand.

Measurements taken at my computer chair ~11ft away from the sub. (Sub only, doors open)

Flight of the Phoenix plain crash scene (swithey's DTS disc 6) yields a max spl of 114db.

WOTW lightning Scene : 114db max
Tripod stomp :111db max (caused clip light to flicker a few times)
Tom running from Tripod (heat ray): 115db! max(Caused a little bit more clip light activity this time)

Will be back later with more updates. So far this sub greatly exceeds my expectations...and also shows me a new side of the Ep1500. More on this later.

Edit: Re-measured Tipod stomp out of curiosity since it is the lowest of all three measurements. It is actually around 113db, again with some clipping.

**Ilkka** · **03-31-07, 05:14 PM**

Quote:

kramskoi wrote:

one must simply live with inductance issues with these high xmax, high weight (magnet) drivers...the old Tumult inductance graph is a good example of this...keep me posted on your tests Ex...good work...have fun with the new beast...martin

Actually that's the new Tumult inductance graph.

**bossobass** · **03-31-07, 06:09 PM**

Inductance does indeed matter. I gained approximately 7dB at 100Hz using the Tumult MKII vs the original. Since I use 100Hz as a crossover point for some source material, that translates to a much better time in smoothing out the 100-200Hz band.

The standard LP in bass management is 4th order. That would mean that the sub is attenuated 6dB at 100Hz (using a 100Hz X-over, of course), and if you're already down 7dB at 100Hz, before the LP, it makes for an impossible crossover region vs a driver that's flat to 200Hz and higher.

TCSounds has done a great job with the latest generation of subs, IMO.

Exo...I certainly wouldn't mind seeing a no LP graph, done nearfield, on-axis, if you get the time.

Great thread, much appreciated!

Steve...loved the comment about designing a ported sub with 3Hz tune

Bosso

**Exocer** · **03-31-07, 06:24 PM**

Bosso, I am curious as well. Unfortunately I'll need a longer mini-rca cable or a replacement extension before this happens.

**kramskoi** · **03-31-07, 09:14 PM**

Quote:

Exocer wrote:

Very good point.

In person, the TC-3k just appears to be the larger driver from a pure displacement standpoint. Including the 1/3rd of the Tumult's surround makes the two a bit closer, but the TC-3k would still appear to be the larger driver.

Is it a significant size difference? Absolutely not.
Do the pictures convey the size differences well? Absolutely not

I wish you guys were able to press a button and transport over just to see for yourself to draw your own conclusions.

hello Rob, i'm not sure why this is even an issue anymore

...having both seen these drivers up close, the veracity of the Sd observations are quite real...there is a noticeable difference in cone area...the TC3000 simply moves more air...

...love the side-by-side against the Tumult, not to say the tc3k is better, but it definitely overshadows the Tumult in stature...

**Mark Seaton** · **03-31-07, 10:40 PM**

Quote:

Exocer wrote:

Very good point.

In person, the TC-3k just appears to be the larger driver from a pure displacement standpoint. Including the 1/3rd of the Tumult's surround makes the two a bit closer, but the TC-3k would still appear to be the larger driver.

Is it a significant size difference? Absolutely not.
Do the pictures convey the size differences well? Absolutely not

I wish you guys were able to press a button and transport over just to see for yourself to draw your own conclusions.

Just caught the latest additions here. Nice stuff. One thing to note, I've measured the Avalanche 15, it's got a LOT of Le at low frequencies. When I adjusted to fit measured data, the numbers were not far from the TC-3k in the shorted inductance at lower frequencies. IOW, your comparative measurements don't surprise me. Seeing the response and distortion measurements outdoors is where the *possible* implications come into play. The 3 component Le model generated by LEAP is very useful, but not directly comparable to more common measurements at 1kHz. The ramification isn't always so much the drop of the top end, but peaks in the upper range of the response and sometimes overall loss in expected sensitivity at other frequencies.

So far as the Sd question, surround width most certainly affects the Sd (effective radiating area). As I'm continually reminded of with various vendors, don't assume the number you see is accurate. Sometimes OEM's use "nominal" Sd values for all woofers they make of a nominal size. Some give more accurate numbers. It's not a monumental issue, but it does shove the models around somewhat and enough to not get so worried about very small differences until you correlate a model with reality. The tall/narrow profile of the TC-3k will have a larger Sd. Sometimes the smaller Sd can be helpful, especially if you want deeper response in a small box. It's just another parameter to juggle and match with the others.

I haven't seen a recent TC-3k other than what they had at CES which might not have been current. Can you tell us how the tall surround behaves when pushed in or out to significant travel? Is there any visible deformation? A couple second input at very low frequency in free air would also let you see this in use.

**kramskoi** · **03-31-07, 11:36 PM**

Quote:

Mark Seaton wrote:

Just caught the latest additions here. Nice stuff. One thing to note, I've measured the Avalanche 15, it's got a LOT of Le at low frequencies. When I adjusted to fit measured data, the numbers were not far from the TC-3k in the shorted inductance at lower frequencies. IOW, your comparative measurements don't surprise me. Seeing the response and distortion measurements outdoors is where the *possible* implications come into play. The 3 component Le model generated by LEAP is very useful, but not directly comparable to more common measurements at 1kHz. The ramification isn't always so much the drop of the top end, but peaks in the upper range of the response and sometimes overall loss in expected sensitivity at other frequencies.

So far as the Sd question, surround width most certainly affects the Sd (effective radiating area). As I'm continually reminded of with various vendors, don't assume the number you see is accurate. Sometimes OEM's use "nominal" Sd values for all woofers they make of a nominal size. Some give more accurate numbers. It's not a monumental issue, but it does shove the models around somewhat and enough to not get so worried about very small differences until you correlate a model with reality. The tall/narrow profile of the TC-3k will have a larger Sd. Sometimes the smaller Sd can be helpful, especially if you want deeper response in a small box. It's just another parameter to juggle and match with the others.

I haven't seen a recent TC-3k other than what they had at CES which might not have been current. Can you tell us how the tall surround behaves when pushed in or out to significant travel? Is there any visible deformation? A couple second input at very low frequency in free air would also let you see this in use.

Mark, i'll jump in here and say that at extreme excursions, i've noticed "white marks" on the surrounds of each driver in my 2x15 sub...it's only happened once or twice...once with max spl <10 Hz sinewave testing and once with feedback from the behringer mic (?)...

with program material, even upwards of 120+ dB, i have'nt noticed this happening...it seems that the surround will deform as it approaches its xmech (~92mm p-p)...the inductance issue is interesting and as i suspected...i've found that both the Tumult and the Tc3k have similar rolloff characteristics up top...

it seems that Le is especially hard to control with these high xmax/heavy magnet drivers, especially when you consider the amount of coil moving around in the motor...Faraday/shorting rings seem not to be the regulators they're portrayed to be in real world observations...

Good comments and observations as always Mark...thanks

martin

**Exocer** · **04-01-07, 12:17 AM**

Quote:

Mark Seaton wrote:

Just caught the latest additions here. Nice stuff. One thing to note, I've measured the Avalanche 15, it's got a LOT of Le at low frequencies. When I adjusted to fit measured data, the numbers were not far from the TC-3k in the shorted inductance at lower frequencies. IOW, your comparative measurements don't surprise me. Seeing the response and distortion measurements outdoors is where the *possible* implications come into play. The 3 component Le model generated by LEAP is very useful, but not directly comparable to more common measurements at 1kHz. The ramification isn't always so much the drop of the top end, but peaks in the upper range of the response and sometimes overall loss in expected sensitivity at other frequencies.

So far as the Sd question, surround width most certainly affects the Sd (effective radiating area). As I'm continually reminded of with various vendors, don't assume the number you see is accurate. Sometimes OEM's use "nominal" Sd values for all woofers they make of a nominal size. Some give more accurate numbers. It's not a monumental issue, but it does shove the models around somewhat and enough to not get so worried about very small differences until you correlate a model with reality. The tall/narrow profile of the TC-3k will have a larger Sd. Sometimes the smaller Sd can be helpful, especially if you want deeper response in a small box. It's just another parameter to juggle and match with the others.

I haven't seen a recent TC-3k other than what they had at CES which might not have been current. Can you tell us how the tall surround behaves when pushed in or out to significant travel? Is there any visible deformation? A couple second input at very low frequency in free air would also let you see this in use.

The surround did NOT visibly deform when pumping out about 114db (close to clipping the Ep1500) during WOTW earlier. Even manually pressing in on the cone does not cause visible deformation.

Reading martin's response leads me to think I may not have a powerful enough amp for this alignment to cause the surround deformation.

**ssabripo** · **04-01-07, 11:42 AM**

excellent work ROb. Have you done any outdoor GP's on the T3K and AVa15 yet? I'm interested to see how each behaves in GP, particularly how that thin surround may affect the numbers at high SPL for <10% THD.

Deon at one point commented to me that they went with the smaller surround, but they doubled them up, as they were getting destroyed by the car audio guys...the dual surround helped but I'm sure it caused a difference (dont know how bad, if at all) in the FR measurements.

is there a way to tell by inspection if you can see dual surrounds?

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