Spectrum Analyzer Results & Jeff's Take on the US Tax System!

[Strabo]

Ricktate - See - this is why we were going to buy that Behringer deq 2496. To be able to compensate a bit for the room. Despite it being a bandaid. I'll sit in the sweet spot for a good listen today.

The forum ate my previous post but this was my point (in a nut shell).

You are measuring the speakers, room, and equipment in this "test".

Of the three things listed, fixing the room will have the biggest impact.

Forget the crossovers for now (sorry Dean) they will make a difference but not as big as fixing the room.

From the numbers you posted:

It looks like you have a mild mid bass hump followed by a mild trough (it's hard to tell because is was a small sample) but it looks fairly smooth.

Then a jump in the high frequencies. Do you have a lot of hard surfaces in the room, hard floors, windows, bare walls?

I would look into some sound absorption.

[D-MAN]

I think that you also need to use pink noise which is what most build-in generators produce in RTA's.

It should be understood that you are also measuring the room and its various responses with modes, etc. The speakers will not be isolated in any manner in such a test.

DM

[MarkBK]

Only one dimension of the future room is known: 28'. The dimension is arbitrary and likely will be dictated by whatever's best for the khorns. I'll be all over those workmen to get those corners straight. []. The rope caulk trick is on my long list for a try down the road. It sounds removeable. If not, I may not try. Going to try to get hubby to come home early. Going to do some listening now in different parts of the room (esp the sweet spot) so I have a good reference for the x-over swap.

Rope caulk is removeable - but you will not want to do so - it has no negative effect - it just dampens the horn or speaker frame and removes "hash" ringing. You will benefit greatly from using the long wall for the Khorns when you do remodel.

[Strabo]

Here's a quick graph in Excel.

Let's see if the forum will accept it as an upload.

Edit, it didn't.

From the info (ignoring the bass), you have a small dip around 4k. That's a good thing in my book, others may not like it.

Then you have a monster problem, in my opinion, from 5k - 8k range which coincides to your complaint. That is why I suggested starting with some absorption. Soak up those peaks rather than letting them bounce around the room over and over.

That is nearly an octave. Will a crossover change be able to attenuate 3/4 of an octave?

[BiggerIsBetter]

sorry did not see the last pages of psots, nothing to add

[Deang]

"Then a jump in the high frequencies. Do you have a lot of hard surfaces in the room, hard floors, windows, bare walls?"

Do I get the Idiot of the Day Award? I was looking at those numbers and interpreting them as a drop in output with increasing frequency. If I'm indeed looking at this backwards, then definitely do something about those hard/reflective surfaces asap.

[pauln]

I'm sticking to my first recommendation - buy a pair of Heresys and devote a couple of years to learning what all this is about. Acoustical and electronic engineering are not subject matter expertise to be gained lightly or quickly. Most spend years developing their knowledge and skill. There is no short quick path. The musical part takes even longer.

[BiggerIsBetter]

OK, I read ALL of the pages this time. You clearly seem to have a suckout in the low/mid crossover region and your listening impression certainly support that. I am not up on the AA, or who modified it and how. BUT, I would simply try reversing the polarity of the mids and redoing the measurements (looking at 400-600 hz) and listening. Someone may have inadvertently changed the polarity when modifying a crossover (i.e. like forgetting to change the polarity of the mids/high when migrating from a B-2 to a , your drivers may be incorrectly marked, or hook up, or??? Bottom line is it is very easy to swap the mids polarity (at the crossover) and give it a listen.

My highs also measure 'bright' and sound bright. While I appreciate all of the very technical explanations for this, I am getting ready to simply start experimenting with AT settings. Sometime I think we can make things too complicated, either that or I am not capable of overly technical solutions. []

[meagain]

The floor is wall to wall plush thick carpet. 13' beyond speaker wall, it's hard.

Ceiling is 8' high with beams every 3.5-4'. Wall between speaks is basically a window area temporarily covered with strech plastic (bad windows) overwhich is a thin gauzey curtain. Side walls: one a brick wall with pictures & ledges. Other has a 8-9'? bank of window very high on the wall (starting at 5'3"?) Plastic also but not covered with curtain/shades. Furniture is on this wall (chest, etc). Sofa faces speakers abut 9-10' away. Walls are lightly textured like a plaster trowel effect. TV (embarrasingly) is temporarily in front of curtained window on speaker wall (husband requirement). It's butt ugly! TV used to be in the corner where a khorn is now. It won't be acceptable come spring.

I bought them without hearing them prior. Had to jump on them & I don't regret it but we've been agonizing on how to rearrange things and keep scratching our heads. Moving the TV to the side wall would be a rough change. No view from kitchen, etc.

Maybe we'll try it out this weekend. Then the speakers would be about 14' wide.

[meagain]

I'm sticking to my first recommendation - buy a pair of Heresys and devote a couple of years to learning what all this is about. Acoustical and electronic engineering are not subject matter expertise to be gained lightly or quickly. Most spend years developing their knowledge and skill. There is no short quick path. The musical part takes even longer.

LOL Heresy's? I again assume this is a joke. Maybe I should revert back to my KG4's then & continue listening for a "couple years". At least they have some bass! Or maybe I could buy those cute little cube speakers everyone here raves about. []

Pauln posted a condensed pdf chart the first page about 7 posts down. Not sure if this helps, but it's a visual.

[Deang]

You can't change AT settings without shifting the crossover points.

It's not likely Rick screwed up the connections -- I'm the only one that does that.

[meagain]

I'll take some pics of our x-overs & the wireing before putting in Ricks. I've yet to open this bass bin door, etc. I couldn't find diagrams/pictures to compare to to see if things are right.

Dean - What do you think of that Behringer DEQ for my situation?

[Strabo]

I was looking at those numbers and interpreting them as a drop in output with increasing frequency. If I'm indeed looking at this backwards, then definitely do something about those hard/reflective surfaces asap.

It looks like average level jumps about 4 or 5db (eye-balling the graph)from 5k - 8k.

I added a 10 point moving average to the graph and it really shows the lift. Looking at it this way, it could be interpreted as a 6-7db lift.

hmmm, there is another minor blip at 13k - 14k of about 3db's. Could this be a harmonic of the 5k - 8k bump? If so, could it be equipment driven or is it a function of the room?

[BiggerIsBetter]

So for example, with a type B, if you change the AT position to the tweeter, it will change the value it see from the mid (before the AT) cap. I could see where that would change the total capacitance seen by the tweeter. I would wonder by how much and whether it would be significant given it's a first order and most of the rolloff if occurs due to the driver anyway.

I bought my speakers from a guy who got them from the original owner, who said they were stock and swore they were never opened up. When I took a look, the polarity to both mids was reversed and the tweeters were out of phase with each other. "Strange" things can happen. Strangest thing is, I am not convinced that they sounded better after I corrected all of the polarities []

It's free and easy, there is certainly a problem in the crossover region and if room optimization does not take care of it, she will have to try something....that will likely involve crossover changes anyway.

"I'll take some pics of our x-overs & the wireing before putting in Ricks. I've yet to open this bass bin door, etc. I couldn't find diagrams/pictures to compare to to see if things are right."

Even if they look "right", switching the polarity of the mids (most simply at the terminal strip on the XO out to the mid driver) will not hurt anything and will give you are real quick way of getting the answer.

[Strabo]

Lets try to upload another graph.

It worked.

This is the right speaker with a 10 point moving average.

[meagain]

bigger - I hope he understands what you are talking about with this polarity stuff (visually), cuz I sure don't. I know I asked him if he hooked them up right and he said 'yea - red goes to red' (or something like that).

Strabo - cool chart. Wish I understood it better.

[Jeff Matthews]

Meagain, on polarity, red to red and black to black. For example, outside on the bottom of the left side of the KHorn should be a trap door for access to the woofer bin. There should be 2 posts serving as receptacles for the wire that goes from the crossover (in the top section of the KHorn (that's inside the top bin where youre mid and tweet are) to the woofer. You will see that the receptacles are either red and black or have + and - on them, or both. Then, when you follow the wire up into the top bin to the crossover, the crossover definitely has connections at that wire that are colored red and black. You will see that the connection of the wire from the woofer to the xover occupies the 2nd pair of a total of 4 pairs of screw receptacles on the xover. What they are saying is follow the pairs of wires to make sure they are kept in line - red to red and black to black. You don't want them getting crossed anywhere, or your polarity will be off/reversed.

The xover screw sets are appropriately labeled to show where the wires go to it from the tweet/high, the mid, and the bass.

If you remove the top cover of the top bin, you'll see the xover right there with all of its screw sets on one side and labeled.

Like this:

4pairs of

screw sets connection

x (red) high/wires from the tweeter horn

x (black)

x (red) mid/wires from the mid horn

x (black)

x (red) low/wires from the bass bin/woofer

x (black)

x (red) input/speaker wire from receiver

x (black)

When you look at the back of the tweet and mid horns where the wires connect, you'll see little colored dots and maybe +/- marks on them to indicate what is red (or +). The idea is not to cross wires. Red out of the tweet horn to red into the xover pair of screws for the tweet, etc.

Your wires from the tweets should be gray with a little red line, and plain gray (accounting for 2 wires in the pair). The one with the red line is what we call "red." Some replacement wires use a white line, instead of red. Same idea. It really doesn't matter what's on the wire. What matters is that you use the SAME wire from the red/+ output from the tweeter horn and follow it to the red/+ input on the xover set of screws for the high input. Same goes for mids, lows and input.

Man, that was long.... Hope it helps clarify.

[BiggerIsBetter]

You would have to check a lot of thing to make sure the polarity is "correct." Again, the simplest way is to just switch the mids and listen measure. Don't think, don't analyze, just switch red and black on the mids output. IF, you get better response through 400-600ish hz, i.e. more output without that big dip, then you had a polarity issue and you can dig further to figure it out. It will not hurt anything, and it's free.

I just think that it is too much of a coincidence to have that large of a gap in that region to be purely room. I may be wrong, switch the wires and 10 minutes will tell......

[meagain]

Jeff! Very very helpful. Bravo & thanks! I'll print that out.

Bigger - thanks. It was suggested to me to check a couple weeks ago when we got them, but given that these are 3,000 pounds each on on thickish carpet - etc. Well, I fully blame my husband for not opening the bass bin door, etc. I told him to, but he poo-poo'd the concept saying he hooked it up right. Just assuming the parts he didn't need to touch were perfect and he also said we'd definiately hear a problem immediately. I'm understanding that it might not necessarily be 'in your face' if it's off.

I tell ya - I'll sure have egg on my face if this wire thing turns out amiss.

[BiggerIsBetter]

I don't have Khorn, but didn't think you needed to open the base bin to get to the crossover in order to switch the connections. Though they are heavy, that should not take more than a few minutes. I did forget the other option. By switching the polarity of both you are verifying that both mid are in the correct phase with the woofers (or as best as possible for your crossover type).

You should also switch the polarity of just ONE mid (doesn't matter which one). This will verify that both your mids are in phase with each other. If there is a wiring mistake, may be more likely that it only occurs on 1 side.

In either test, you are looking for flatter (i.e. more output in the xover region). If you do get flat output, either sit back and enjoy or dig further to identify the cause.