Thread: 3x12+2"wNL8's&4Xti4000's

Originally Posted by Gene Hardage

The little lights were vertical rows of red LED's for each frequency. It's a box with the display on the front along with a mic input and a pink noise generator. Don't know about the phase display or if it does that or what that is.

So it was just an RTA. You will not get any phase information out of that "box".

You really need to look at a real measurement system. Getting proper crossovers is not easy (you have no idea of any kind of "time") with an RTA.

Getting the time right (and remember that there is a different time "delay" with each of the different low pass filters-so they have to be adjusted (via delay) in order to get them to "line up") is practically impossible.

It may "look" like it is right-but is not actually right.

I am working on a little paper that shows how a measurement system can "look right", but in reality it is wrong. Depending on how it is setup. And RTA is the worst case (or best case-depending on the perspective) in not "telling the truth".

Originally Posted by Ivan Beaver

So it was just an RTA. You will not get any phase information out of that "box".

You really need to look at a real measurement system. Getting proper crossovers is not easy (you have no idea of any kind of "time") with an RTA.

Getting the time right (and remember that there is a different time "delay" with each of the different low pass filters-so they have to be adjusted (via delay) in order to get them to "line up") is practically impossible.

It may "look" like it is right-but is not actually right.

I am working on a little paper that shows how a measurement system can "look right", but in reality it is wrong. Depending on how it is setup. And RTA is the worst case (or best case-depending on the perspective) in not "telling the truth".

It will be interesting to see what these things read using the current fancy measuring tools vs. his old school device and 30+ years of speaker tuning experience. Hopefully someone will come along in this area and bring the latest wizbang tool set.

Hello Gene,
Cool project. How much did you spend per cabinet on components, speakers, horn, driver?
And what frequency is the horn crossed over at?

Regards, Jack

Crude delay alignment can be done with an RTA by inverting the speaker and looking for the minimum SPL as delay of the time-forward transducer is increased. Of course, this method does require some knowledge of what the crossover is doing since you can choose the wrong value easily.

Originally Posted by Mark DeArman

Crude delay alignment can be done with an RTA by inverting the speaker and looking for the minimum SPL as delay of the time-forward transducer is increased. Of course, this method does require some knowledge of what the crossover is doing since you can choose the wrong value easily.

But there is more to it than that. Yes you may be able to get "higher level" at the crossover point. HOWEVER- you ALSO have to look at what is happening above and below the crossover point (freq wise).

Due to fact that the drivers don't have a "perfect" response- you could end up with a "hole" on either side of crosover. If you are using a single freq for a test signal (and changing delay time) you will not see this hole(s).

So the correct alignment may end up with not quite as much "gain" at crossover-but a more even response across the overall band-which is a good phase alignment.

Agreed the "adjust time until the level is at max (or min-depending on how you do it)" method can get you close-but it is not always the best setting. But is better than nothing.

Of course figuring out which driver is the "most forward" is not always easy. Once you throw a low pass filter on a driver-the "effective time" is not the same. So the one in the "front" physically-may actually be the last one to "produce sound"-due to this filter.

Originally Posted by Ivan Beaver

But there is more to it than that. Yes you may be able to get "higher level" at the crossover point. HOWEVER- you ALSO have to look at what is happening above and below the crossover point (freq wise).

Due to fact that the drivers don't have a "perfect" response- you could end up with a "hole" on either side of crosover. If you are using a single freq for a test signal (and changing delay time) you will not see this hole(s).

So the correct alignment may end up with not quite as much "gain" at crossover-but a more even response across the overall band-which is a good phase alignment.

Agreed the "adjust time until the level is at max (or min-depending on how you do it)" method can get you close-but it is not always the best setting. But is better than nothing.

Of course figuring out which driver is the "most forward" is not always easy. Once you throw a low pass filter on a driver-the "effective time" is not the same. So the one in the "front" physically-may actually be the last one to "produce sound"-due to this filter.

Agreed with all you said but I just thought I would remind everyone that the older tools will work to get you close, (with good listening) if you don't have access to the more advanced stuff.

Originally Posted by Jack Arnott

Hello Gene,
Cool project. How much did you spend per cabinet on components, speakers, horn, driver?
And what frequency is the horn crossed over at?

Regards, Jack

They were bit pricey because the components are pretty nice - all Faitals. The horn is crossed at 1200. Just winding down from doing a full set up for the Chill Lounge in downtown Tampa. I really like the sound of those Faital 18's. With two doubles each driven by a Crown Xti6002 per side I finally have some whompum. I must be one of the few blathering on this board that lives in the Tampa area. I have another date coming up over in Orlando.

Originally Posted by Gene Hardage

The horn is crossed at 1200.

Thanks

They were bit pricey because the components are pretty nice - all Faitals.

That is not even close to answering the question. Is it impolite to ask?

PS, if you are not up to speed, I sell speaker components, so I know that Faitals are not in the Chinese category, and I am also pro-DIY.

Regards, Jack

If anyone wants to know the price of them you'll have to call Ramsdell and ask. I lost track of stuff because there was a lot of new stuff being bought at the same time - Presonus StudioLive24 - Crown Xti amps - more subs - etc.



Here's an interesting clip I found of the event they were used at in Tampa.

edit: link - http://youtu.be/l7i1HsvffT4

hmmm. the clip doesn't show - I'll try an older one...



this is what happens when it gets dark...

http://youtu.be/TH-3-W5qC3E

Originally Posted by Gene Hardage

hmmm. the clip doesn't show - I'll try an older one...



this is what happens when it gets dark...

The Samba Girls of Chill Lounge Night - YouTube

This reminds me that...

A SF Bay Area based guitarist with many years of big name touring and recording credits will not leave is house when not on tour unless the job meets his "regular price". EXCEPT for the local samba school that calls and offers him $75 to play behind them. He says the view is MAGNIFICENT from where he stands ;-)!

Originally Posted by Lee Brenkman

This reminds me that...

A SF Bay Area based guitarist with many years of big name touring and recording credits will not leave is house when not on tour unless the job meets his "regular price". EXCEPT for the local samba school that calls and offers him $75 to play behind them. He says the view is MAGNIFICENT from where he stands ;-)!

Yeah I'm thinking they really need a slide geetar player in that mix too