Dayton neo 275-035 question

[matg]

if i was to put, say, 18 of these in a line array, how low could i cross them? there would be 18 per side, sort of a psudo ribbon, 18 lined up to make about a 15" tall tweeter.

[marlboro]

Have you read the Jim Griffin paper? Are you going the cut the flanges which you have to do to avoid combing which will start at 5000hz? At what slope are you going to use? At what size midrange are you crossing them to? 18 is not long enough to keep them in the nearfield unless your are going to listen to them at about 4 feet away, and you remain seatedall the time. How big is the midrange array?

Questions, questions!

> if i was to put, say, 18 of these in a line
> array, how low could i cross them? there
> would be 18 per side, sort of a pseudo
> ribbon, 18 lined up to make about a 15"
> tall tweeter.

[matg]

well, i was planning on using the press fit from the back model, did i list the wrong part number? I was thinking about the onkyo buyout 4x6's with about 18 of those per side set too. And for slope, prolly 12 db but maybe a third order, still in the planning/is this worth it stage.

So based on what you are saying, the tweeters will start to comb above or below 5khz?

i could just do a modified/hybrid array, and stack a bunch of the onkyo's and then put some big-azz tweeter in the middle, like a wwwwwwwwwtwwwwwwwww. thinking of a matching center channel too. Oh, the 4x6 array would be about 71-72" tall.

> Have you read the Jim Griffin paper? Are you
> going the cut the flanges which you have to
> do to avoid combing which will start at
> 5000hz? At what slope are you going to use?
> At what size midrange are you crossing them
> to? 18 is not long enough to keep them in
> the nearfield unless your are going to
> listen to them at about 4 feet away, and you
> remain seatedall the time. How big is the
> midrange array?

> Questions, questions!

[curt_c]

> if i was to put, say, 18 of these in a line
> array, how low could i cross them? there
> would be 18 per side, sort of a psudo
> ribbon, 18 lined up to make about a 15"
> tall tweeter.

As Marlboro indicates, you will not have much of an array even though you will drop a significant amount of cash on the purchase.

That said, with that many tweeters, you could likely cross a 2K, or even 1500 Hz without excursion limitations at reasonable SPL’s. However, the harmonic distortion of that tweeter increases substantially below about 2200 Hz. The severe peaking just before roll off would necessitate you to electrically cross at a higher frequency though and still provide a lower frequency acoustic transfer function, which would mitigate the HD issue somewhat.

Note that the BG RD50 is touted to cross as low as 150 Hz. Add up all your mids and tweeters, and see how close you come to the cost of one of these…

C

[matg]

well, in quantity, the little rear mount neos are pretty cheap. Even if i put 40 per side, it would still cost less than a pair of the BG RD50's. and, if i decide to get crazy and do a matching center channel, i bet i could get a good deal on 130 or so of those little neos. i know, it wouldn't look as cool, but the neos go higher and i am not afraid of cutting holes. Would i be better off with just one big tweeter crossed around 2500? note, this is a thought to go with 18 per side of the onkyo 4x6 buyouts, so i think the BG would be a bit overkill for a budget array. Just looking for thoughts and advise from those with more array experiance than me.

i will try to find that white paper that marlboro mentioned.

> As Marlboro indicates, you will not have
> much of an array even though you will drop a
> significant amount of cash on the purchase.

> That said, with that many tweeters, you
> could likely cross a 2K, or even 1500 Hz
> without excursion limitations at reasonable
> SPL’s. However, the harmonic distortion of
> that tweeter increases substantially below
> about 2200 Hz. The severe peaking just
> before roll off would necessitate you to
> electrically cross at a higher frequency
> though and still provide a lower frequency
> acoustic transfer function, which would
> mitigate the HD issue somewhat.

> Note that the BG RD50 is touted to cross as
> low as 150 Hz. Add up all your mids and
> tweeters, and see how close you come to the
> cost of one of these…

> C

[marlboro]

<A HREF="http://www.pesupport.com/cgi-bin/config.pl?read=319834">http://www.pesupport.com/cgi-bin/config.pl?read=319834</A>

Please do a little reading on array designs. Your choices for how to do this are not matching the experience and research of Dr. Griffin. After spending all the time and effort you will not like the results in the direction that you are currently going. The press in neos cannot be made close enough together to avoid combing issues that are clearly audible, and sould like warbling and a drop in the treble. And even with a digital equalizer and extensive measurement, you can't adequately fix it.

Additionally, its rather hard to make a decent array without being able to measure they system. 12 db octave crossovers are not sufficient for crossing those neo's that low, you probably need 48 db octave electronic(behringer). Most people use electronic crossovers. Passive's are difficult enough to buiuld adequately for a point source, but when you throw in multiple speakers, they get very difficult, and expensive.

If you are going to use 69 cent NSB's for the midrange then I would take Thy's method of using plnars for the tweeters.

I mean..... you can do it all, but when you're done you'll be telling people that you built an array and in your opinion they are not all they are cracked up to be.

You can't just throw them together like a point source, they require lots more development time.

Marlboro

[matg]

so what you are suggesting is that the only way it is possible to get acceptable high freq responce in to use planar tweeters? The tiny neos just are not small enough to get the low center to center spacing needed to avoid excessive combing? then PE should change their ad copy to reflect this?

Besides, i don't think that any amount of equalization would change combing as this is a result of peaks and nulls created as you move through the vertical plane and one tweeters output blends with the one above/below it. And would not this combing only be noticed as you move verticaly in the listening field? I realize what you are trying to say but with the close c to c spacing the neos would provide, would not the combing be pushed fairly high, way higher than a reasonable xover freq, reguardless of slope.

I am going to read the white paper, but i seem to remember other (on this site) people having done the neo line and liked it.

i still would like to know if it is possible to do a large mid or woofer array and one fat tweeter in the middle like a wwwwwwwwwtwwwwwwwww. i realize this may not be a "true line array" but i don't care about the label i put on this thing.

>
> <A HREF="http://www.pesupport.com/cgi-bin/config.pl?read=319834">http://www.pesupport.com/cgi-bin/config.pl?read=319834</A>
> Please do a little reading on array
> designs. Your choices for how to do this are
> not matching the experience and research of
> Dr. Griffin. After spending all the time and
> effort you will not like the results in the
> direction that you are currently going. The
> press in neos cannot be made close enough
> together to avoid combing issues that are
> clearly audible, and sould like warbling and
> a drop in the treble. And even with a
> digital equalizer and extensive measurement,
> you can't adequately fix it.

> Additionally, its rather hard to make a
> decent array without being able to measure
> they system. 12 db octave crossovers are not
> sufficient for crossing those neo's that
> low, you probably need 48 db octave
> electronic(behringer). Most people use
> electronic crossovers. Passive's are
> difficult enough to buiuld adequately for a
> point source, but when you throw in multiple
> speakers, they get very difficult, and
> expensive.

> If you are going to use 69 cent NSB's for
> the midrange then I would take Thy's method
> of using plnars for the tweeters.

> I mean..... you can do it all, but when
> you're done you'll be telling people that
> you built an array and in your opinion they
> are not all they are cracked up to be.

> You can't just throw them together like a
> point source, they require lots more
> development time.

> Marlboro

[matg]

didn't you do a line of neos?

>
> <A HREF="http://www.pesupport.com/cgi-bin/config.pl?read=319834">http://www.pesupport.com/cgi-bin/config.pl?read=319834</A>
> Please do a little reading on array
> designs. Your choices for how to do this are
> not matching the experience and research of
> Dr. Griffin. After spending all the time and
> effort you will not like the results in the
> direction that you are currently going. The
> press in neos cannot be made close enough
> together to avoid combing issues that are
> clearly audible, and sould like warbling and
> a drop in the treble. And even with a
> digital equalizer and extensive measurement,
> you can't adequately fix it.

> Additionally, its rather hard to make a
> decent array without being able to measure
> they system. 12 db octave crossovers are not
> sufficient for crossing those neo's that
> low, you probably need 48 db octave
> electronic(behringer). Most people use
> electronic crossovers. Passive's are
> difficult enough to buiuld adequately for a
> point source, but when you throw in multiple
> speakers, they get very difficult, and
> expensive.

> If you are going to use 69 cent NSB's for
> the midrange then I would take Thy's method
> of using plnars for the tweeters.

> I mean..... you can do it all, but when
> you're done you'll be telling people that
> you built an array and in your opinion they
> are not all they are cracked up to be.

> You can't just throw them together like a
> point source, they require lots more
> development time.

> Marlboro

[marlboro]

I said:

1. If you use neo's, you need to use the ones with flanges so that you can get their center to center distance close enough to get the combing to start out beyond 13khz-15Khz. You cannot do that with the push in ones.

You need to ignore the advertising hype, even from PE.

2. I said that I don't recommend using 69cent midranges, unless you are using Planars or ribbons which go much lower that the neo's can do. This is because the 69 cent models just don't have enough depth to do the job, nor enough xmax or anything else. If you use them, then you need to be covering more of the midrange between 1600 and 2600(where the neos can cross if you use enough of them and use at least 24 db octave crosses.) Planars or ribbins will do that, but domes will not.

The neo's are fine down to about 2500 in a group of more than 15 per side, with 24 db/octave crossovers, preferably electronic. Below that they start screeching. If you use the neo's then you need a midrange that can handle the range between 1000 and 2600 adequately, and 69 centers cannot, especially in the range between about 1300 and 3000. (You also need to laquer the cones of the 69 cent-ers, but that's another story, and remember that you will also need a woofer for both sides.).

Depending on where you cross the midranges and how big they are, you may have combing between them, and also horozontal combing between the midranges and the tweeters.

You can do anything you want. I'm just a guy who likes to follow the research so that I am getting the best possible for the money.

Many people don't believe no stinkin' research. I'm not one of them.

3. Designing an array takes a careful combination of speakers, and reseach of the designs.

Marlboro

[matg]

this is the start of a new project and i am just trying to eliminate some paths before i start out into a new mess. I have built many, many speakers in the past, and even a couple of modified arrays. I just want to build a decent one for me to keep without taking out a second mortgage on the house.

i have decided against the 4x6 onkyo buyouts for a couple of reasons, first, they look awfull, second, i would have to spend tooooo much on planars to get the cheapo things to mesh. not a good idea, agreed.

belive me, i am not taking the throw caution to the wind and screw research approach, i am only trying to feel out ideas before droping the $$$. i do appreciate your input. forgive me if i came back harsh, i guess last night was not a good night for me to be on the computer while my other half had other ideas of how i should be spending my time, but that is neither here nor there.

actually, for a budget array, i am considering the pioneer 4 1/2" extended range driver, 290-010. i have used these in the past and they do sound fairly nice in a group of 4 per side. but this is still just a thought, need to find time to really sit down and calculate, without other distractions.

thanks, mat

[marlboro]

Why don't we continue this privately. Email me at <A HREF="mailto:calipso@epix.net">calipso@epix.net</A>. Its getting pretty far down in the cue and a pain to get to.

Most people here aren't terribly interested in array designs, mostly because of the labor, and the expense. It took me two years to build mine. Source point speakers rarely took over a couple of months. Not all of it was build time, some was design, purchase of all the amplification, measurement after the fact etc., but cutting more than 104 holes in solid red oak and hardwood and pine took an enormous amount of time by itself.

Marlboro