Crown I-Tech 4x3500HD

Re: Crown I-Tech 4x3500HD

Looks like 2000 watts per channel at 4 ohms, the 3500 number is 'burst'.

The burst spec on the Itechs is a very real and useful spec, at least for subwoofers. I don't know of many kick drums that have a duration of more than 20ms...

But, that does sadden me, as that means it's just two IT5000HDs in one chassis. And, it costs more than two IT5000HDs.
 
Re: Crown I-Tech 4x3500HD

Just saw the print ad where they specifically mention powering a 4889 with it. Ch1-2 for lows and Ch3 for mids and Ch4 for Highs?!? The intended setup was for two boxes.

Whoever is writing ad copy for Harmon needs to be shit-canned. That's the most expensive and least desirable amp setup for a 4889 I've ever heard of. Even if you stretch it out to 4 boxes (2ohms a side for ch1-2) you are still really underpowered on the 15's....

Now give me an amp rack with 2 12000HD's and one 4x3500HD and we are talking! I'd have the ability to run 8 boxes in 2 zones with a rack that weighs next to nothing!
 
Re: Crown I-Tech 4x3500HD

About time they released a 4 channel amp. 4 channel amps are very popular, atleast over here. I hope they have done their homework properly and bring a serious product out on the marked so they really can compete, me thinks 4 channel amps are a bit pricey right now and needs some more competition.

IMHO
 
Re: Crown I-Tech 4x3500HD

soundz like its the new "flagship" amp to work with the new line array system
...but u could also put 2 vt4889 on it
i would gess its called the economy setting in performance manger dsp
 
Re: Crown I-Tech 4x3500HD

I don't know of many kick drums that have a duration of more than 20ms...

Multiply that by 10, and you'll have something like the length of the volume envelope of a tightly damped kick drum. A typical RnR kick's volume envelope will be over 300ms long.

The peak output of that will be only a fraction of the total duration, but I don't want anyone thinking that kick drum is a 20ms event.
 
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Re: Crown I-Tech 4x3500HD

A consistent sample from a beautifully tuned and played DW 20" kick. Recorded with a Beta 91 about 4" from the beater head. A more typical large diaphragm dynamic located in/near the hole is not going to be as well defined I'm sure. Fundamental is around 63Hz - likely part of the old school EQ "rule of 63's" where you might want to highlight 63Hz and 6.3kHz.

20msKick.jpg
 
Re: Crown I-Tech 4x3500HD

A consistent sample from a beautifully tuned and played DW 20" kick. Recorded with a Beta 91 about 4" from the beater head. A more typical large diaphragm dynamic located in/near the hole is not going to be as well defined I'm sure. Fundamental is around 63Hz - likely part of the old school EQ "rule of 63's" where you might want to highlight 63Hz and 6.3kHz.

20msKick.jpg

Langston, thank you for posting this, I was going to post something similar once I got time. Looking at the selection range, you selected exactly 20ms. In this case, I'm going to say that a 20ms burst spec is, in fact, a useful spec for these amps.

Here's my reasoning: the 'burst' rating is just a bit less than 3dB more than the usual average power, but in your picture, the kick drum attack in the 20ms window is actually about 6dB more than the decay right after the 20ms window. This means that a 'burst' power rating of even 6dB above average power could be useful, at least for this specific kick drum.

Sure, the 'burst' rating may not matter much for EDM or bass guitar or other sustained sources, but for a kick drum, it's definitely useful.
 
Re: Crown I-Tech 4x3500HD

Multiply that by 10, and you'll have something like the length of the volume envelope of a tightly damped kick drum. A typical RnR kick's volume envelope will be over 300ms long.

The peak output of that will be only a fraction of the total duration, but I don't want anyone thinking that kick drum is a 20ms event.

Agreed. While the entire duration may be longer, the part that will take advantage of the 'burst' spec seems to conveniently fit inside a 20ms window.
 
Re: Crown I-Tech 4x3500HD

A consistent sample from a beautifully tuned and played DW 20" kick. Recorded with a Beta 91 about 4" from the beater head. A more typical large diaphragm dynamic located in/near the hole is not going to be as well defined I'm sure. Fundamental is around 63Hz - likely part of the old school EQ "rule of 63's" where you might want to highlight 63Hz and 6.3kHz.

20msKick.jpg

Langston,

Pass this through a HP-LP combination like what comes before a real subwoofer, and post it again ;)~;-)~:wink:
 
Re: Crown I-Tech 4x3500HD

Agreed. While the entire duration may be longer, the part that will take advantage of the 'burst' spec seems to conveniently fit inside a 20ms window.

Except that the frequency content in that peaking region is outside the bandpass of the subwoofers. Pass that signal through the subwoofer bandpass filtering, and then look at it.

Then, too, you have to figure that the amp is current limitin after those 20ms, since it can make the voltage swing. Therefore, the frequency at which the input will matter most is the box tuning frequency, since this is the point where Rvc is closest to Rdc and the current demand from the amplifier is the largest. Lets assume Fb is 35Hz, so it is the current demands at 35Hz that will matter most. The period of 35Hz is more than 20ms.
 
Re: Crown I-Tech 4x3500HD

Again, I think envelope will spread out a bit with a more typical mic and mic technique.

Same view using a newer version of the software:

KickNoFilters.png


25Hz 4th order BW high pass and 80Hz 4th order LR low pass filters applied. Same selection window:

Kick25Hz4thBWHP80Hz4thLRLP20msSelect.png


Same filters, new selection window:

Kick25Hz4thBWHP80Hz4thLRLP23msSelect.png
 
Re: Crown I-Tech 4x3500HD

One thought that comes to my mind is what would make me want to chose this line over Lab Gruppen's 4 channel lines with Lake processing? Pricing is similar/close on both the Lab and the I-Tech.
 
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