Coming soon, subjective SQ tests.

**Brian Bunge** · **02-20-07, 10:25 PM**

It was in a huge concrete room at least 8' from any wall so there was little to no room gain. But yeah, it was pretty loud. I just wish I'd kept my K2. I could use it to power my new subwoofer when it's done. And I personally love having an LT circuit with a sealed sub. Nothing quite like flat response to 10Hz in room. I still have the LT so I will modify it to work with the new sub.

**Exocer** · **02-20-07, 10:30 PM**

Quote:

Brian Bunge wrote:

It was in a huge concrete room at least 8' from any wall so there was little to no room gain. But yeah, it was pretty loud. I just wish I'd kept my K2. I could use it to power my new subwoofer when it's done. And I personally love having an LT circuit with a sealed sub. Nothing quite like flat response to 10Hz in room. I still have the LT so I will modify it to work with the new sub.

Hey, that sounds like a good plan to me. Any idea which drivers you'll be using? Assuming you go with the Dayton RS woofers, wouldn't you have to be a little concerned about using an LT? Would using multiple drivers lessen the effect of Xmax limitations?

**kramskoi** · **02-21-07, 02:58 AM**

Quote:

Ilkka wrote:

What do you mean? They have almost identical Sd, so both will have to move exactly similarly to produce same SPL. Only the power needed will differ.

also the amount of power that the voice coil can utilize/absorb and not compress or burn up...i don't understand...

89dB @ 1w/1m
86dB @ 1w/1m

which one is louder at 1w/1m? which one is louder at 1000watts? when we are discussing dynamics, the Tumult, theoretically, would have to survive twice its rated power...but then the tc3000, with more coil available could jump past it again at double its rated power...i'm not so sure the short xbl^2 coil would survive that shootout...

having had both a Tumult and TC-3000 i can tell you that the 3000 utilizes more cone area period...and it's not as close as you think

...even the tc2000 utilizes more, with its half-roll surround...

the stated sensitivity trap works both ways...either manufacturer could be making generous claims...it is a significant gap in stated sensitivity however...the tc3000 initially debuted with somewhat of an SPL slant...

**Ilkka** · **02-21-07, 05:07 PM**

Quote:

kramskoi wrote:

also the amount of power that the voice coil can utilize/absorb and not compress or burn up...i don't understand...

89dB @ 1w/1m
86dB @ 1w/1m

which one is louder at 1w/1m? which one is louder at 1000watts? when we are discussing dynamics, the Tumult, theoretically, would have to survive twice its rated power...but then the tc3000, with more coil available could jump past it again at double its rated power...i'm not so sure the short xbl^2 coil would survive that shootout...

having had both a Tumult and TC-3000 i can tell you that the 3000 utilizes more cone area period...and it's not as close as you think

...even the tc2000 utilizes more, with its half-roll surround...

the stated sensitivity trap works both ways...either manufacturer could be making generous claims...it is a significant gap in stated sensitivity however...the tc3000 initially debuted with somewhat of an SPL slant...

Don't get me wrong guys, I don't want to badmouth either driver, as a matter of fact I just recently purchased some TC-Sounds drivers.

I just want to say that you shouldn't look too hard on the published specs, especially sensitivity. The published value is only close to the truth at some certain frequency, you must also look at the (simulated) frequency response. Tumult and TC-3000 have very different frequency responses, TC-3000 has a wide peak in 50-90 Hz range while Tumult is much flatter. Below ~40 Hz Tumult seems to be around 2.5-3 dB more sensitive than the TC-3000. In 50-90 Hz range the TC-3000 takes the lead by being around 2-4 dB more sensitive.

My next measuring session will have some representatives from both company, so at least then we will see some real world numbers.

Here's a sneak peak at TC-2000 15" NF frequency response (small wiggles are some room reflections). +/- 3 dB from 19 Hz to >300 Hz.

**Brian Bunge** · **02-21-07, 05:11 PM**

I'll either be using dual or quad RS 15" HO's. The original plan was to use 4 of them, but the box is even too big for my own tastes. I might end up with two boxes, each with two drivers. As long as I don't go overboard with the power the LT will work fine.

**WillyD** · **02-21-07, 06:38 PM**

Quote:

Here's a sneak peak at TC-2000 15" NF frequency response (small wiggles are some room reflections). +/- 3 dB from 19 Hz to >300 Hz.

Not surprising. I tested my TC-2000 with no filters up to 500Hz, and it definitely fared well. I figured it would though...

**bossobass** · **02-21-07, 09:34 PM**

Just a note here...it's not 86dB vs 89dB, it's 86.8dB vs 88.6dB. That's 1.8dB difference, not 3dB.

And, as Ilkka points out, those numbers are hardly relevant as a comparison in the subwoofer's BW as a ratio of difference.

Yes, Will did post that measurement which showed the value of the shorting ring, IMO. Ilkka's graph looks very similar to Will's.

Now, If Kram would post one of the 3K...

Ilkka the sub builder? Tell us more, my friend?

Bo

**Exocer** · **02-22-07, 02:34 PM**

Ilkka, feel free to share details with us.

On another note. Lets talk wiring possibilities.'

Right now, pairing off each 2ohm VC in series for a 4ohm load per pair is the plan. What makes most sense is to hook up each pair of 4ohm VC's to an individual channel on the Ep1500. Theoretically, each VC should see around 450 watts.

Lets say someone messes with the gain on the ep1500 and has one at half level and the other was left at full. Could this be fatally detrimental to the driver? Should I simply run the Ep1500 bridged and wire the TC3k so that it presents an 8ohm load?

**Ilkka** · **02-22-07, 07:18 PM**

Quote:

bossobass wrote:

Ilkka the sub builder? Tell us more, my friend?

Bo

I will. But not yet.

Ilk (

)

**Exocer** · **02-22-07, 08:39 PM**

Ok...well guys, expect some updates after the driver arrives. If anyone has question LMK.

**Ilkka** · **02-22-07, 09:01 PM**

Quote:

Exocer wrote:

Ilkka, feel free to share details with us.

On another note. Lets talk wiring possibilities.'

Right now, pairing off each 2ohm VC in series for a 4ohm load per pair is the plan. What makes most sense is to hook up each pair of 4ohm VC's to an individual channel on the Ep1500. Theoretically, each VC should see around 450 watts.

Lets say someone messes with the gain on the ep1500 and has one at half level and the other was left at full. Could this be fatally detrimental to the driver? Should I simply run the Ep1500 bridged and wire the TC3k so that it presents an 8ohm load?

Use as much power as you have. There is no such thing as too much power. My friend and I just tried a single TC-2000 in a 3.2 cu-ft enclosure with ~2.4 kW, and it sounded great. One may be able to mechanically bottom (or not...41mm Xmech) the driver with the amp at full tilt, but one must know/hear when he must stop pushing any further. I would hate to see the clipping lights at any point sooner.

The low frequency roll-off of your electronics also gives some extra protection. Always remember that when looking at the simulations. Add a 1st order 10 Hz HP, and that's more closer to what you are in reality.

**Ilkka** · **02-22-07, 09:42 PM**

Found a little something relating to the Sd discussion we had.

Quotes are from the HTGuide forum.

Quote:

kramskoi wrote:

winisd pro auto-calculates Sd=830 cm^2 (for TC-3000)...IF this is true then...5.64 liters Vd swept !!! vs. 4.86 liters for a Tumult 15d2...incredible!

Quote:

Mark Seaton wrote:

Don't believe everything you read on the internet...

I would be very surprised if the effective Sd is 830cm ^2. The parameters posted used 830cm^2 for all of the 15" drivers, and I'm all but certain that's well overstated for the TC-2000. Maybe Kyle could to some fact checking for us and determine what are some more realistic values. I would guess a range of 750-800 cm^2.

**Exocer** · **02-22-07, 09:45 PM**

Yeah one of the main concerns was amp clipping. Options seem very limited because the Ep1500 isn't rated to drive a bridged 2ohm load, so the next option would be using a single channel for 700watts of power @ 2ohms. My guess is the Ep1500 would clip A LOT with this configuration.

Options so far:

Give each pair of VC's their own channel. Wire each VC pair in series for 4ohms of resistance per pair/per channel.

Pair off the VCs in series then wire each pair in parallel to each other for a 2 ohm load, wire to a single channel (Theoretically this would clip a lot more than the other two options).

Wire each VC pair in series, then wire the pairs to each other in series for 8ohms of resistance. Bridge the Ep1500 for ~900watts. (seems the safest route at this point)

**Brian Bunge** · **02-23-07, 05:36 AM**

I accidently ran an EP2500 into a 1 ohm load in bridged mode for about an hour. It didn't hurt the amp, but I promptly changed the wiring back to a 4 ohm load as soon as I realized what I'd done.

**Exocer** · **02-23-07, 12:27 PM**

Quote:

Brian Bunge wrote:

I accidently ran an EP2500 into a 1 ohm load in bridged mode for about an hour. It didn't hurt the amp, but I promptly changed the wiring back to a 4 ohm load as soon as I realized what I'd done.

Scary

**bossobass** · **02-23-07, 03:52 PM**

Quote:

Ilkka wrote:

Use as much power as you have. There is no such thing as too much power. My friend and I just tried a single TC-2000 in a 3.2 cu-ft enclosure with ~2.4 kW, and it sounded great. One may be able to mechanically bottom (or not...41mm Xmech) the driver with the amp at full tilt, but one must know/hear when he must stop pushing any further. I would hate to see the clipping lights at any point sooner.

The low frequency roll-off of your system also gives some extra protection. Always remember that when looking at the simulations. Add a 1st order 10 Hz HP, and that's more closer to what you are in reality.

Hmmm...I'm struggling a bit with this post.

There is definitely a such thing as too much power. 2.4KW can definitely fry the big SGLC VC. It depends on the source, the room and the duration of high level playback, so I certainly wouldn't recommend as a general rule that no amount of power is too much power.

Clip lights are an indication that you're exceeding the system's capabilities, if the power plant is carefully sized to the system and application. This, IMO, is a much better way to know when the system/application limits are being exceeded. Thermal meltdown, however, as in the case of too much power being available, is a silent killer that gives no warning.

Even if the VC doesn't fuse under very high input over extended periods (like playing techno at a party), the repeated high heat/cooling cycle is bad for ANY glue, no matter how good the glues used in constructing the driver may be, long term.

As far as the roll off providing any pretection, it's actually the air spring that provides excursion protection down low. Modeling excursion to 25% of Xmax should provide adequate excursion headroom in the case of transient peaks at VLF.

As an extreme example, the same driver in an IB installation is much easier to bottom. Call the reason higher efficiency, if you will, but that efficiency is due to the lack of air spring.

Bosso

**Exocer** · **02-23-07, 05:44 PM**

Righto bosso. The lack of air spring is indeed the reason IB's are easier to bottom. As Vb increases there is less of an air spring. This increases efficiency in the lower frequencies which is a sign of having a lower qtc, thus increasing the possibility of meeting or exceeding excursion with less power.

*Thought it would be helpful to explain that a little further for those who are following and are wondering what we're talking about.

The problem of overpowering the TC-3k isn't even a possibility with my design goals/budget. In case you guys don't remember, my current situation is very financially restricted. When you pay for tuition out of your pocket and lets not mention the $160+ textbooks :raped:

how am i affording the TC3k again?...thats a topic for another thread

So, anyone who is under the impression that I will feed this driver more than an Ep1500, ep2500, or BKA is mistaken.

Donations are welcome!

**Ilkka** · **02-23-07, 08:48 PM**

Quote:

bossobass wrote:

Hmmm...I'm struggling a bit with this post.

There is definitely a such thing as too much power. 2.4KW can definitely fry the big SGLC VC. It depends on the source, the room and the duration of high level playback, so I certainly wouldn't recommend as a general rule that no amount of power is too much power.

Clip lights are an indication that you're exceeding the system's capabilities, if the power plant is carefully sized to the system and application. This, IMO, is a much better way to know when the system/application limits are being exceeded. Thermal meltdown, however, as in the case of too much power being available, is a silent killer that gives no warning.

Even if the VC doesn't fuse under very high input over extended periods (like playing techno at a party), the repeated high heat/cooling cycle is bad for ANY glue, no matter how good the glues used in constructing the driver may be, long term.

How many SGLC drivers or even XBL^2 drivers have you melted with clean music/movie signal? With a typical crest factor of 10 dB, 2.4 kW peaks cause a 240W RMS power in the VC. Naturally pure sine waves are a completely different matter. No VC will hold if much higher than RMS rated sine wave is run any longer than ~5-30s.

I don't have your experience with all sorts of drivers, but I would suspect it's not that easy to melt a VC with clean music/movie signal even though the peaks would go much higher than what the RMS spec of the driver is.

I am willing to eat my words after I've melted my first VC.

Quote:

As far as the roll off providing any pretection, it's actually the air spring that provides excursion protection down low. Modeling excursion to 25% <-?? of Xmax should provide adequate excursion headroom in the case of transient peaks at VLF.

Sorry about the bad wording. By system I meant electronics. Simulations always assume that the inputted frequency response is dead flat down to DC. But in reality that's not the case. DVD player, pre/pro/receiver, EQ, amp etc; combine the VLF roll-off of these and you are nowhere close staying flat to DC. 1st to 2nd order (or even higher) slope below 5-10 Hz or even higher isn't anything uncommon. Remember to add that to your simulations.

Combine this and the above, and I wouldn't hesitate using 2x more powerful amp that what the excursion simulation would suggest. After all, that's only 3 dB more for those transients...

Quote:

As an extreme example, the same driver in an IB installation is much easier to bottom. Call the reason higher efficiency, if you will, but that efficiency is due to the lack of air spring.

Bosso

That's correct.

**kramskoi** · **02-23-07, 10:34 PM**

Quote:

Ilkka wrote:

Found a little something relating to the Sd discussion we had.

Quotes are from the HTGuide forum.

mark kinda of ticked me off with that...but i was trying to tell him that winisdpro was "autocalculating" these values...it was'nt values just off the top of my head...the point is the Sd on the tc3000 is greater than the Tumult 15d2 period, once again...

**Ilkka** · **02-23-07, 11:10 PM**

Quote:

kramskoi wrote:

mark kinda of ticked me off with that...but i was trying to tell him that winisdpro was "autocalculating" these values...it was'nt values just off the top of my head...the point is the Sd on the tc3000 is greater than the Tumult 15d2 period, once again...

WinISD calculates the Sd from the Dd (effective diameter) value. Basically it's just another way of saying the Sd. Though we don't know how accurate TC-Sounds' numbers are. Like Mark said, anything over 800 cm^2 is gener

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