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AESpeakers TD Series group buy!!! - Page 12

post #331 of 768
10/20/11 at 2:25pm
Quote:
Originally Posted by thylantyr View Post

You want to mate great drivers with crummy chip amps?

You think the T amps are crummy? I thought they were highly regarded.
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post #332 of 768
10/20/11 at 3:05pm
Quote:
Originally Posted by noah katz View Post

You think the T amps are crummy? I thought they were highly regarded.

I think they're good in some ways, but I would not use them as they are not load independant designs:

http://www.michael.mardis.com/sonic/...e/default.html
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post #333 of 768
10/20/11 at 3:31pm
Quote:
Originally Posted by noah katz View Post

You think the T amps are crummy? I thought they were highly regarded.

Which ones are you talking about, the product called "T-AMP" or the Tripath Class T AMPlifier architecture ?

Tripath went out of business.
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post #334 of 768
10/20/11 at 4:01pm
T-amp
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post #335 of 768
10/20/11 at 4:28pm
"Am I calculating incorrectly?"

Good doc, Your calculations are more or less right for 2 pi space aka standing outdoors in a field. In a room, the wall reflections increase sensitivity quite a bit. The amount of gain is both frequency, placement, and treatment dependent. You could easily pick up 3-6db vs. 2 pi space model in room in the mid-bass region. Also, the lower your noise floor, the higher the sound level will seem. I like 95-100 db while in my car on the highway, open windows, with a noise floor of 80db because my ears are adjusting to protect given how much ambient noise there is. At that level, I can't hardly hear myself while yelling, but the sound doesn't seem "too loud". In a dead quiet room, the same 95-100db sound out of the quiet, is painfully loud because the muscles in my ears have gone for max sensitivity. Our ears actually work much like our eyes. Walk into a room after being out in the snow and you won't be able to see because your eyes have adapted to protect them from too much light. After a while, they re-adjust. Our ears work much the same way.
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post #336 of 768
10/20/11 at 5:04pm
Quote:
Originally Posted by LTD02 View Post

"Am I calculating incorrectly?"

Good doc, Your calculations are more or less right for 2 pi space aka standing outdoors in a field. In a room, the wall reflections increase sensitivity quite a bit. The amount of gain is both frequency, placement, and treatment dependent. You could easily pick up 3-6db vs. 2 pi space model in room in the mid-bass region. Also, the lower your noise floor, the higher the sound level will seem. I like 95-100 db while in my car on the highway, open windows, with a noise floor of 80db because my ears are adjusting to protect given how much ambient noise there is. At that level, I can't hardly hear myself while yelling, but the sound doesn't seem "too loud". In a dead quiet room, the same 95-100db sound out of the quiet, is painfully loud because the muscles in my ears have gone for max sensitivity. Our ears actually work much like our eyes. Walk into a room after being out in the snow and you won't be able to see because your eyes have adapted to protect them from too much light. After a while, they re-adjust. Our ears work much the same way.

GoodDoc, Scott is planning to use 4 2226J's per main. Those are 97db sensitive drivers. Four of them would be 103db at 1w. That is about about 105db at 12ft with 10w. Of course, he would have 3 of these for his L/C/R so it isn't absolutely necessary to have a full 105db from any one speaker, although that does meet spec.

10w was an exaggeration. Yes, 50w would be good. That would be good for at least 3db of headroom at 105db in a 20ft room by my rough calcs.

As far as chip amps are concerned, I was not referring to the Sonic Impact amp. The DTA-100 measures far better and does 30w at 8ohms with .05%THD. It might be barely under powered, but I doubt it given the highly efficient setup.

I'm not suggesting the chip in the DTA is the end-all, but if Scott has been sitting on his project for 2 years saving up for some 2000w/channel uber pro amps, he could certainly use this as a stop gap.

Thylantyr, how much headroom do you deem necessary, 20db?

Do all chip amps suck? How about the IRS2092, LME49810, and LM4702? Properly implemented, those are all very high quality chip amps, IMHO.
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post #337 of 768
10/20/11 at 5:15pm
Quote:
Originally Posted by LTD02 View Post

I like 95-100 db while in my car on the highway, open windows, with a noise floor of 80db because my ears are adjusting to protect given how much ambient noise there is.

Your brain is protecting you from excessive subjective loudness, but I don't believe our ears have a protective mechanism.
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post #338 of 768
10/20/11 at 5:23pm
Quote:
Originally Posted by coctostan View Post

The DTA-100 measures far better and does 30w at 8ohms with .05%THD.

The DTA-100 is described as Class-T; is that interchangeable with T-amp?
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post #339 of 768
10/20/11 at 5:39pm
"Your brain is protecting you from excessive subjective loudness, but I don't believe our ears have a protective mechanism."

they do. the muscles push and pull on this and that and actually reduce the effects of the pressure. i'm half watching the game right now, so i will try to dig up some research on this topic at a later point.
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post #340 of 768
10/20/11 at 6:05pm
Quote:
Originally Posted by noah katz View Post

T-amp

Looks like a really nice headphone amplifier. /seriously
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post #341 of 768
10/20/11 at 6:17pm
Quote:
Originally Posted by thylantyr View Post

Looks like a really nice headphone amplifier. /seriously

You don't think 30 W is enough for a 100 dB/1W CD (assuming active XO)?
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post #342 of 768
10/20/11 at 6:54pm
Quote:
Originally Posted by noah katz View Post


You don't think 30 W is enough for a 100 dB/1W CD (assuming active XO)?

30 clean watts perhaps, but most amp measurements I've seen show increasing distortion at the upper limits of their output. My guess is the distortion for a 30w amp has a good chance of increasing substantially from baseline past 25w. My ideal amp would provide the maximum calculated wattage I would ever need at 75% output so I don't approach the knee of increasing distortion. Although I realize its overkill, it soothes my OCD .
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post #343 of 768
10/20/11 at 7:01pm
Quote:
Originally Posted by Gooddoc View Post

30 clean watts perhaps, but most amp measurements I've seen show increasing distortion at the upper limits of their output. My guess is the distortion for a 30w amp has a good chance of increasing substantially from baseline past 25w. My ideal amp would provide the maximum calculated wattage I would ever need at 75% output so I don't approach the knee of increasing distortion. Although I realize its overkill, it soothes my OCD .

Actually, it is about 1% at 40w and .05% at 30w both into 8ohms. That is for the TK2050 in the DTA-100a.

I'm not saying the DTA-100a is something great. I was just suggesting that for $300, he could power his 3 mains actively and get moving on the project, instead of trying to save up for $2500 worth of amps that are huge overkill. He could go with 3 EP2000's instead for $600.
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post #344 of 768
10/20/11 at 9:26pm
Quote:
Originally Posted by noah katz View Post

You don't think 30 W is enough for a 100 dB/1W CD (assuming active XO)?

Low wattage amplifiers have terrible clipping headroom. Again, it's not about the watts persay. I don't use low headroom amplification for a good sound system.
You can if you want, millions of people do.

(I run bridged PLX3402 on my EV DH1 driver / HP640 horn, I won't have it any other way)
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post #345 of 768
10/20/11 at 9:51pm
Quote:
Originally Posted by coctostan View Post


Actually, it is about 1% at 40w and .05% at 30w both into 8ohms. That is for the TK2050 in the DTA-100a.

I'm not saying the DTA-100a is something great. I was just suggesting that for $300, he could power his 3 mains actively and get moving on the project, instead of trying to save up for $2500 worth of amps that are huge overkill. He could go with 3 EP2000's instead for $600.

Agreed. There's nothing wrong with strategic compromise - most all of us do it on one level or another. I would bet those amps would be audibly indistinguishable from any other at reasonably loud levels. Using them until the budget allows for the more capable amps would be a smart move IMO as well. After all, at least for me, the times I crank to ear bleeding levels are the minority by far.
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post #346 of 768
10/20/11 at 9:52pm
Quote:
Originally Posted by noah katz View Post

You don't think 30 W is enough for a 100 dB/1W CD (assuming active XO)?

I guess it would depend on the desired output level @ the LP, the amount of CD horn boost ( if needed ) and the source. I have some music that has >30 db transients.

If for instance, your average listening level at the LP is requiring 1 watt of power into the compression driver, and you have a 30 db transient, you need 1kw of power to faithfully reproduce that transient. ( assuming the CD can take it )

For my LCR project, I will be using a QSC PLXII 2502 for each speaker, one channel for the 8R BMS co-axial driver ( 425 watts ) and the other channel for the dual 4R woofers in parallel ( 1250 watts )
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post #347 of 768
10/21/11 at 1:57am
I'm not really following this thread as I already have a dozen TD drivers, but I see that there are 200 or so units in the GB.

I hope that it helps John J with the buiness as well as everyone particpating getting a good price.
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post #348 of 768
10/21/11 at 4:47am
Quote:
Originally Posted by A9X-308 View Post

I'm not really following this thread as I already have a dozen TD drivers, but I see that there are 200 or so units in the GB.

I hope that it helps John J with the buiness as well as everyone particpating getting a good price.

...and he can expect a second wave of buyers a few months from now once people start showing off some polished designs from the group buy drivers.
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post #349 of 768
10/21/11 at 5:44am
Quote:
Originally Posted by michael hurd View Post

I guess it would depend on the desired output level @ the LP, the amount of CD horn boost ( if needed ) and the source. I have some music that has >30 db transients.

If for instance, your average listening level at the LP is requiring 1 watt of power into the compression driver, and you have a 30 db transient, you need 1kw of power to faithfully reproduce that transient. ( assuming the CD can take it )

For my LCR project, I will be using a QSC PLXII 2502 for each speaker, one channel for the 8R BMS co-axial driver ( 425 watts ) and the other channel for the dual 4R woofers in parallel ( 1250 watts )

Specifically, Scott's setup will be >100db sensitive for both the woofer and horn.

Let's set it up for THX reference which is 85db with 20db transients. This is loud by most sane standards.

@15ft with his 103db LF section he would need ~.17w to reach 85db. For the 20db transient he would need ~17w. Mind you, this is with only one speaker playing.

I don't know how sensitive your speaker is or what levels you listen at, but I highly doubt Scott would need the 425w you are using on your HF section. That would give him ~120db at the LP. Are you listening at an average of 90db with 30db peaks? Even with compensation, the BMS coax CDs are at least 103db sensitive right? Are you listening at 100ft?

Of course, there is nothing wrong with that extra power and I would want around 3-6db of headroom, but I don't see any use for 15db of headroom. I'm not recommending the DTA-100's as a final or ultimate solution, just a stop gap.
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post #350 of 768
10/21/11 at 5:54am
Thread Starter 
Quote:
Originally Posted by Gooddoc View Post

This is not to challenge, but to learn why a 10w amp would be sufficient for a 100dB sensitivity driver? Considering my upcoming build with the TD drivers I just ordered it's a topic that I've been thinking about. At a 12ft distance to the MLP, my back-of-the-napkin calculations say that it would require about 50w to reach reference of 105 dB(disregarding potential and variable room gain).

Am I calculating incorrectly?


Yeah, I think 10Watts isn't enough. 10Watts is only 10dB of gain. Why even bother with high sensitivity designs if we cap them around 110dB. At 12 to 15Ft many individuals are going to hit 30dB peaks and will need 120dB SPL capabilities from their mains. (Scott and I are a few of those). For a 100dB setup, 100Watts is still the minimum for a custom HT Room to ensure clean max peaks. Headroom is key!! 110dB limits are for people that do not hear amp clipping and do not know what "limited" dynamics sound like.

FWIW, Im not a T-amp fan at all outside of maybe a near field office setup.

Im not sure high powered pro audio amps are the a good main speker solution either, I have found a happy middle ground with ATI amps. I do not need more the 60Watts for the Tweeter and 100Watts for the woofers.
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post #351 of 768
10/21/11 at 5:57am
Thread Starter 
Quote:
Originally Posted by coctostan View Post

Are you listening at an average of 90db with 30db peaks?

30dB peaks exist in many great action movies and 90dB is about 80dB at 12 to 15ft in a treated room.

So that question is an easy, YES for many individuals.
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post #352 of 768
10/21/11 at 5:59am
Thread Starter 
Quote:
Originally Posted by A9X-308 View Post

I'm not really following this thread as I already have a dozen TD drivers, but I see that there are 200 or so units in the GB.

I hope that it helps John J with the buiness as well as everyone particpating getting a good price.

+1, it seems like this was a great success for John. I hope it pays off for him and his business.
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post #353 of 768
10/21/11 at 6:09am
Quote:
Originally Posted by penngray View Post

30dB peaks exist in many great action movies and 90dB is about 80dB at 12 to 15ft in a treated room.

So that question is an easy, YES for many individuals.

I guess you listen at higher levels than I listen at. I'm not referring to subwoofer levels either.
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post #354 of 768
10/21/11 at 6:17am
Thread Starter 
Quote:
Originally Posted by coctostan View Post

I guess you listen at higher levels than I listen at. I'm not referring to subwoofer levels either.

I don't listen loud, what I do want is having dynamic peaks not clipped during performance scenes. A crappy little 10Watt T-amp screams CLIPPING.

This isnt even about average listening levels. Just like buying a 500HP car is not about driving to work or the store. (Yep, silly car analogy )

Why even build a high end system that has the possibility of 120dB and limit it?? Its like having a Sports car that can fit a 500HP engine and telling the dealer, "Nah....I will take the 80HP 2 stroke instead"

When you need the power to get clean SPL, you simply won't have it. I do not build my HT system to be awesome just for 95% of the time. I build it to be incredible for that other 5% of the time. That other 5% is when people wet their pants, leave with a crazy "OMFG grin". That other 5% is what separates a great system from the world of BOSE that offers distortion and clipping as a selling point

Its all choice though, as long as people know the content levels, the numbers behind their choices then more power to them.
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post #355 of 768
10/21/11 at 6:38am
i agreed. if i spent nearly $1k on my speakers. i definitely do not want to feed it a $100 50w amp.

why not pick up some Emotiva UPA-2s? the pre-own units can be had for aroud $200-$250. they will deliver a clean 120w to each channel.
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post #356 of 768
10/21/11 at 7:05am
Penn, except I suggested a 30w (50w @ 1%thd) amp to a guy running 4 2226J's per channel. That might limit him to 110db @ the LP from a single speaker. Someone else took chip amp to mean 5-10w and put those words in my mouth.

Smokarz, the UPA-2 might be a better deal, sure. I was just suggesting the cheapest minimally adequate amp I could think of off the top of my head. Do you know of 3 UPA-2's selling for $125ea? I'd probably jump on that myself.
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post #357 of 768
10/21/11 at 7:38am
Thread Starter 
I didn't wonder about the 10Watt part of it. 50Watts is okay, I will still want more for the woofers so that small amounts of boosting does not force the amp to clip.

I have owned Emotiva LPA-1, XPA-5 amps...they are okay and they do their job but their noise floor isn't great at all. I also own many Outlaw M2200 200Watt monoblocks, 3 will be used with my dual JBL2226s bass bins. I have tried the outlaws with the CDs and the noise floor is too high, the ATIs seemed to be the best consumer brand for that purpose that I have found. Since the ATIs worked, I stopped looking.
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post #358 of 768
10/21/11 at 7:54am
Quote:
Originally Posted by coctostan View Post

Penn, except I suggested a 30w (50w @ 1%thd) amp to a guy running 4 2226J's per channel. That might limit him to 110db @ the LP from a single speaker. Someone else took chip amp to mean 5-10w and put those words in my mouth.

Not to put words in your mouth, but this is what kicked off the discussion...

Quote:
Originally Posted by coctostan View Post

A 10w chip amp would give you the headroom you need...seriously. Anything beyond that is not headroom, but a paperweight.

Measurements of my system show greater than 110 dB transient peaks for reference level HT, even for a single speaker. And music is far more demanding than HT due to higher sustained power demands. As I've said, getting an affordable underpowered amp as a temporary compromise is a reasonable suggestion and will get that 95 percent of performance. But as Penn pointed out, it's the 5 percent that is the difference between an average speaker and a great speaker IMO.
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post #359 of 768
10/21/11 at 7:55am
Quote:
Originally Posted by penngray View Post

I didn't wonder about the 10Watt part of it. 50Watts is okay, I will still want more for the woofers so that small amounts of boosting does not force the amp to clip.

I have owned Emotiva LPA-1, XPA-5 amps...they are okay and they do their job but their noise floor isn't great at all. I also own many Outlaw M2200 200Watt monoblocks, 3 will be used with my dual JBL2226s bass bins. I have tried the outlaws with the CDs and the noise floor is too high, the ATIs seemed to be the best consumer brand for that purpose that I have found. Since the ATIs worked, I stopped looking.

And don't you only have the 60w/ch ati? Helluva amp. They rate the S/N at 120db and I trust those guys.

I'd like to find an ATI 1506 for my LCR. It is the older model but 6x150w or 3x450w. Perfect for either active or passive.
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post #360 of 768
10/21/11 at 8:11am
Quote:
Originally Posted by coctostan View Post

.... Do you know of 3 UPA-2's selling for $125ea? I'd probably jump on that myself.

Sorry, if I see them at those prices, they're mine.


Quote:
Originally Posted by penngray View Post

....I have owned Emotiva LPA-1, XPA-5 amps...they are okay and they do their job but their noise floor isn't great at all......

I believe the UPA series have better SN than those XPAs.
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