Started and finished another audio project yesterday afternoon in 5 hours flat!

[chops]

Nah, I don't have any EQs, and the only crossover I have is the one built into the receiver. You can either have it at 50, 80, 100, 150 or 200Hz and it doesn't allow you to set different points for low and high pass.

I did make one more pass at the test tones, this time with the crossover set at 200Hz. I also put the SPL meter on a small table-top tripod which I then placed on the couch exactly where my noggin usually resides (slightly above and ahead of the back of the couch). You'll notice that there is a slight difference in some of the lower freqs, and a greater difference from about 36Hz and up.

Again, the test was done at 90dB @ 50Hz, "C" weighted and "Slow". And again, I provided both charts.

BTW, I'm still not sure what lines you're referring to. The blue and purple ones? If so, where do I move them to?

[DrWho]

Ya, the blue and purple lines...

The light blue indicates +-3dB relative to the purple line in the middle (which should be aligned to the 'zero' point).

The second purple line below the others indicates the -10dB point.

[Guest " "]

what drivers are you using and how does the manufactures data sheet compare to your data?

[DrWho]

He's using the Dayton DVC 15" drivers and the results are modelling up very nicely with the manufacturers data (and all modelling performed in WinISD).

[chops]

and the results are modelling up very nicely with the manufacturers data (and all modelling performed in WinISD).

I'm assuming this is a good thing, right?

BTW, do you think the hallway is in someway helping with the low end of things at all?

[Guest " "]

thats really good to hear.

[DrWho]

The hallway would resonate at 4Hz if I did the math correctly so I doubt it's significantly influencing the low end in such a way as to matter.

[chops]

Ok, so we can scratch the hallway idea out of the way.

So with the measurements thus far, I guess this pretty much confirms the sub-16Hz output I was claiming earlier, huh? []

BTW, in a few minutes, I'm going to run another test, this time keeping both bedroom doors closed and the bathroom door open, which is usually the case. Also, I'm going to run the entire range this time from 10Hz to 20kHz, obviously keeping the Cornwalls on this time.

[chops]

Here's the charts. Boy, I forgot how nasty things looked in this room when you run the entire freq range. I have to say though, from 16kHz to 20kHz, there were some funky harmonics that were coming from my Audigy 2 card. I confirmed this by also listening to those freqs through a pair of headphones right out of the card. I think it might be from WinISD though and not the card. I don't ever remember the TrueRTA software doing that. Oh well...

[DrWho]

What configuration of mains were you using when doing this test? It is

very apparent that there is something awry with your tweeter. At the

very least it should be about 3dB louder, but what is up with its early

roll off too?

As far as your sub - were you still on a 50Hz crossover? If so, it is

apparent that you've got it about 9-12dB too loud [] This

correspondingly makes it seem as if the sub is digging way lower. But

if you turn the sub down to "normal" you're going to say that it

doesn't sound as good that way.

As far as the rest of the response is concerned - the huge dips are due

to room modes. When playing the test tones move your head around and

notice how in some spots the sound totally disappears. This is one of

the reasons it's not very useful to use constant tones to measure a

system. A small work around is to move the meter around within an arm's

reach of the listening position and record the loudest level you

measure. However, it is far more effective to use pink noise (which is

randomly generated signals that hits every frequency such that standing

waves can't build up) and an RTA to distinguish relative volume level

of each frequency, or even better yet an ETF, but we already mentioned

all this.

Often times when your head is in a null you will also hear only the

distortion coming from the driver. However, I think the distortion you

were hearing is due to a blown tweeter or something messed up in the

crossover. I also have an Audigy 2 ZS and have run the WinISD test

tones and they work just fine.

[chops]

What configuration of mains were you using when doing this test? It is

very apparent that there is something awry with your tweeter. At the

very least it should be about 3dB louder, but what is up with its early

roll off too?

What do you mean by configuration of mains? They are crossed over at 50Hz, as well as the sub, if that's what you mean. As for the tweeter output, it baffles me also. Maybe I'm in a null?

As far as your sub - were you still on a 50Hz crossover? If so, it is

apparent that you've got it about 9-12dB too loud This

correspondingly makes it seem as if the sub is digging way lower. But

if you turn the sub down to "normal" you're going to say that it

doesn't sound as good that way.

Yes, the sub is at 50Hz, as are the CWs. ALL level and tone controls on the Technics amp (which is powering the sub) are completely bypassed. In fact, bacause I'm using the "Main In" on that amp, the tone/level controls aren't even in the chain.

I have the sub level on the receiver set at -4dB and the mains at -0dB. If I have it set any lower, I won't get anything out of it. As it is now, I never hear it unless there is something strong below 50Hz. Honestly, the system doesn't sound anything like what the charts show. Everything is very natural and normal sounding.

However, I think the distortion you

were hearing is due to a blown tweeter or something messed up in the

crossover. I also have an Audigy 2 ZS and have run the WinISD test

tones and they work just fine.

The distortion I heard was not from blown tweeters or the crossovers. Like I said in the above post, I heard the same exact distortion at those freqs through headphones plugged directly into the Audigy card, both on the rear of the computer and in the front on the control panel (box).

[DrWho]

I was wondering what version of cornwalls you were running - bone

stock? I know you were working on some other designs with other

squakers/tweeters.

If the distortion is in your headphones too, then there is something wrong with your sound card.

[chops]

Nope, nothing wrong with the soundcard either. I installed TrueRTA and the card produced clean sound all the way up to 20kHz. I tried WinISD again, and the distortion was back. It's obviously something with WinISD Pro. And yes, I have the latest version.

As for my Cornwalls, I'm running the Altec 511B horns with K-55Vs, CT125s, stock K-33Es, modded Type B networks. They are now considered Type CS II. Check these two links...

http://forums.klipsch.com/members/chops.aspx

http://chops.tzo.com/klipsch.htm <-- Be sure to scroll all the way down. There are two galleries.

Speaking of TrueRTA, I hooked up the dbx mic preamp, ran the mic cable into the family room (theater room) and connected it to the RatShack SPL meter, got it calibrated with TrueRTA, plugged in the correction file for the SPL meter, and ran a few tests.

With pink noise, it's still showing the top end rolling off, but with the "Quick Sweep", things seem to be a little more even.

Pink Noise...

Quick Sweep...

[Deang]

If you're using a laptop, then it's possible you might be picking up spurious noise. Shawn mentioned to me that he couldn't use TrueRTA with his laptop because of this, and had to use an external soundcard.

That pink noise plot looks pretty good to me. That's not bad at all for an in-room response with no EQ.

[chops]

If you're using a laptop, then it's possible you might be picking up spurious noise. Shawn mentioned to me that he couldn't use TrueRTA with his laptop because of this, and had to use an external soundcard.

That pink noise plot looks pretty good to me. That's not bad at all for an in-room response with no EQ.

Hi Dean,

I tried using that software on my HP laptop last year and it was unbearable. Now since I'm running Linux on the laptop, I can only use it on my web/file server which is running Win XP Pro C.E. in the bedroom. Even my other tower is running Linux now.

The soundcard is the SoundBlaster Audigy 2 Platinum. I'm using the SPDIF digital out to the stereo and the "L" channel Aux input along with a dbx 760x mic preamp.

So you think that plot looks pretty good, huh? I have to admit, I am rather satisfied with the overall sound so far. []

[johnyholiday]

Any reason the tweeters are not fully baffled?

[Lostinozz]

johnyholiday wrote the following post at 05-30-2006 1:22 AM:

Any reason the tweeters are not fully baffled?

Because they have knowledge neither of us posess! []

[chops]

Alright, so back on the subject of my subwoofer, I'm looking at buying a quality amp for it. I'm seriously thinking about buying a Crown amp. It's the XTi 1000. I'll be using it at 8 ohms bridged mono for 1000 watts to the sub.

Now my main question is, is this amp limited on the low end of the freq range?

Everywhere I look at in the specs, it only mentions +/- 0.25dB from 20Hz - 20kHz at 1 watt. And since my sub produces substantial output down to 14Hz, I don't want to use an amp that can't dig that low on its own.

Or should I not be concerned with this? I guess what the "+/- 0.25dB" means that the amp is almost perfectly flat between 20Hz - 20kHz, and is probably only down -0.50dB at most by 10Hz or so, if that.

Any thoughts on this guys? DrWho maybe, since you seem to really like and know a lot about Crown amps?

Thanks,

Charles

[DrWho]

I posted about this amp in the powered subwoofer section and was all stoked until I heard it was the replacement for the CE line which I really hated.

The XTi lineup is fan cooled so you will want to take that into account - do you have a closet nearby that you can put the amp into?

As far as the frequency response - the crown customer service is extremely good about such things. I would totally give them a call and try to talk to an engineer and see what they tell you. They will be very straight up and help point you in the right direction.

Nevertheless I totally dig the idea of the DSP that comes with it. I don't think there is any such product elsewhere on the market.

[chops]

I posted about this amp in the powered subwoofer section and was all stoked until I heard it was the replacement for the CE line which I really hated.

The XTi lineup is fan cooled so you will want to take that into account - do you have a closet nearby that you can put the amp into?

As far as the frequency response - the crown customer service is extremely good about such things. I would totally give them a call and try to talk to an engineer and see what they tell you. They will be very straight up and help point you in the right direction.

Nevertheless I totally dig the idea of the DSP that comes with it. I don't think there is any such product elsewhere on the market.

Yeah, I saw that thread but didn't want to hijack it, so I just posted about it here. So what is it about the older CE line that put you off so much?

And yes, I plan on probably putting it in my bedroom. I'm still not 100% sure if I'll get it though, or that Samson Servo 600 eventhough it's 400 watts less and fanless. Unless there's another amp you can think of that will give me a little more oomph for about the same price or less and possibly without a fan.