Lowest usable xo for RS150

[goskers]

Hello all,

I will be building a line array shortly which will use the Fountek CD2.0 tweeter, RS150 mid-woofers and TC sounds TC2+ 12's. I want to use the RS150's in an open baffle arrangement as I have come to love the 'boxless' sound.

With 10 of these per side, what should I target for a high pass xo point?

I will be using a DEQX unit so steep filters are not an issue :W

Thanks,

goskers

[cjd]

How loud're you going?

I run mine in a ported box tuned to ~40Hz. I can watch them go WAY beyond their XMax on occasion, so they're quite durable in that respect.

You could probably run them on their natural roll-off on the bottom if you choose: 100Hz-120Hz or so I think? I do suspect they're a bit closed in on the back to work so well open baffle though.

I don't think particularly steep slopes are going to be needed with the drivers you're using - 4th order max. Just watch the breakup on the RS150's.

C

[goskers]

I will try to to explain my goals to the fullest extent.

I would like to use 10 mids per side. My initial thought was to use RS180's but I need something that will run completely clean up to around 2kHz.

I am trying to cross the fountek over at around 1.4-1.6k so having a mid that matches well with this goal is the primary worry.

The TC2+s I would like to have cover the least amount as possible. I am from the school of thought that the least amount of bandwidth a sub covers the better. The use of the RS180 would certainly help out in this respect.

Thanks,

goskers

[cjd]

I'm a fan of 4th order at 1800Hz being the top on the RS150 - I have 'em crossed 4th order at 2100 and they're a bit harsh on occasion.

I'm also a fan of using drivers over the range where they sound good. In this case, understand that the RS150 naturally starts rolling off at ~200Hz with an F3 of 100Hz or something along those lines. Perfectly within the realm of reason with the TC drivers. Simply stop thinking of them as subs, since they're not doing any sub-bass in dipole mode. Just capable bass drivers.

C

[JonMarsh]

I'm a fan of 4th order at 1800Hz being the top on the RS150 - I have 'em crossed 4th order at 2100 and they're a bit harsh on occasion.

I'm also a fan of using drivers over the range where they sound good. In this case, understand that the RS150 naturally starts rolling off at ~200Hz with an F3 of 100Hz or something along those lines. Perfectly within the realm of reason with the TC drivers. Simply stop thinking of them as subs, since they're not doing any sub-bass in dipole mode. Just capable bass drivers.

C

Amen on all accounts... listen to Chris. though the published FR curves might lead you to believe that the RS150 extends significantly higher and smoother than the RS180, it starts getting into energy storage issues above 1800 Hz. His crossover suggestion and experience confirm the audibility of that. For the RS180, I don't recommend going over 1400 Hz on crossover point.

For some "hard" numbers re your dipole midwoofer/midrange array, Linkwitz's spreadsheet will do the trick- then, it all comes down to what SPL you want. The RS150's don't have a lot of Sd, and the Xmax is a bit less, too, so in dipole mode you have to use a little restraint and a higher crossover frequency. I think you'll be fine with Chris's suggestions, but with Linkwitz's spreadsheet (Google is your friend) you can look at the trade-offs in detail.

~Jon

[goskers]

Thanks Jon and Chris,

I shot an email to madisound today regarding the 'vaporware' peerless hds exclusive's and they said shipments for most of those will arrive tomorrow.

These might be the perfect thing for what I am trying to do.

What do you think?

Thanks!

[cjd]

What kind of crossover point are you hoping to reach?

As you lower the crossover to the TC drivers, you invariably lower the crossover to the tweeter. Unless you pick up some rather large planar panels or something, where you may still fail to reach your target low end point but can stretch the top end some. Running a driver out of its ideal range on the top is much more miserable on the ears than crossing to those TC drivers at a higher frequency than you have (seemingly arbitrarily) picked as a "must have".

The Adire Extremis comes to mind as a driver that might have the frequency response (with a 1200-1400Hz top crossover) but I really don't know how that sounds open baffle. Jon? I know you've looked at this, but don't remember your thoughts on the driver at all with respect to open baffle use.

Otherwise you're looking at something like the M8A or other 8" drivers I suspect. The smaller drivers aren't going to give the low frequency extension unless, like the Extremis, they have insane excursion.

I'm still researching and pondering and waiting to try the more serious open baffle setup I have in mind. It'll probably end up being a 5-way (target extension to 10Hz which will require a sealed sub - not gonna try to hit that open baffle!) But, the point of this is to say, I've been thinking about all this stuff.

C

[JonMarsh]

I was pondering the Extremis for open baffle, may still test them, but there are some quirks in there distortion plots that don't please me as much as I'd like to be pleased for what they cost.

It's a tradeoff- you can use an 8" driver with X excursion, or a 6-/2" driver with 2X excursion- the difference in Sd is that significant. I was attacted to the Extremis for the lightweight magnet structure and hopefully low rear masking, but the Peerless may be better. For my dipole project, the Peerless may be a better trade-off- plus it costs less. Will have to see how the distortion compares.

At DFW as I write this- thank heaves for T-Mobile!

~Jon

[capslock]

Hmm, traveling to the US a week from now. Am tempted to order the vaporware from Mad, as that will still be roughly a year ahead of the official Peerless distrubution channels in Europe.

Yes, the white spots for GSM digital phones in the US are becoming smaller. But last time I went there, Corning NY was still not digital.


Eric

[JonMarsh]

They're really scheduled that late in Europe?!? That's hard to believe- I'm hearing September for Australia, though. I don't see them yet in the Madisound online catalog.

Don't talk to me about our antiquated cellular system- we're so doofus over here about some things....

Well, I'd recommend Corning NY over Huntsville- the humidity and temps today remind me more of Singapore than anywhere else. at least I'm back at the terminal in air conditioning waiting for my connection to Dallas, then (shudder!) Chicago. Two of the worst airiports in the US for weather related flight delays in the Summer time... wonder what my chances are of getting to Chicago on time?

~Jon

[cjd]

hehe...

We almost always fly out of Milwaukee, never either of the official "Chicago" airports. But, of course, connecting flights don't give you much choice. :P With the (almost) total lack of anything but hot sunny clear skies I think this summer has been pretty good for Chicago.

Today is a blessing weather-wise here. Was 100+ and 90% humidity two days ago, is low 70's today. Back into the 90's and high humidity this weekend, which means no working in the garage for me.

You know, Taipei is sure nice weather when it's over 100 and 100% humidity... I'm sure much like Singapore. :P

C

[capslock]

They are not scheduled at all yet. This is just an experience, that
- new models usually come out with the yearly catalogue, and only if they became available elsewhere before the old yearly catalogue was printed
- some models never make it
- few models become available in between

The SLS actually were available in between and before Madisound had them, but still about a year after they appeared on the d-s-t website.

This is mainly due to the decision of d-s-t to work with distributors only, and give them territorial exclusivity. It's probably illegal by now, so if some other OEM decided to go retail, it would probably work..

[TacoD]

My local supplier (the Netherlands) list the new peerless series in their catalogue (july). I'll contact them about the availability of those.

[capslock]

@ Taco:
Interesting. I believe the (only?) distributor for the Netherlands is Audiocomponents, and they are somehow affiliated with Intertechnik. If you go to the Intertechnik.de pages and click on the "Partner" button and then on "international" and "more info" besides NL, you will find them listed with the company name "Intertechnik Netherlands" but the old "audiocomponents.nl" address.

Before I knew about the affiliation, I had heard from a Greek guy that he was ordering drivers directly from them at about half the Intertechnik prices. When I inquired to them, they answered that they were not allowed to deal with end customers in the Netherlands and a couple of other countries.

Anyway, when you go to Intertechnik.de and click on the "Neuheiten" tab, you will find that they have almost all the new Excel and Seas drivers (half a year after they were announced!!!), but no new Peerless drivers, unfortunately.


Groetjes,

Eric

[capslock]

@ Jon

Do you have any idea why the US GSM frequencies are around 1900 MHz? One should think in a country with this low a population density, lower frequencies would give you a better coverage for the same number of base stations.

In Europe, where it was developed, GSM started out at 800 MHz, and when they ran out of frequencies, a second band was opened at 1800 MHz.

The first two phone companies to start nationwide service in Germany used 800 MHz (called D net, A, B and C being previous generations of analogue mobile systems), because there was nothing else. The next two companies had to use 1800 MHz (E net). When dual band phones became common place about five years ago, our equivalent of the FCC allowed companies to swap frequencies. E net is now used by all four companies mainly in cities, whereas D is very popular for rural areas.

Greetings,

Eric

[capslock]

Thanks Jon and Chris,

I shot an email to madisound today regarding the 'vaporware' peerless hds exclusive's and they said shipments for most of those will arrive tomorrow.

These might be the perfect thing for what I am trying to do.

What do you think?

Thanks!

Ain't seen nothing yet

[goskers]

I will call them today to inquire about the hds exclusive line. If they have either the 833 or 834 in stock I may just order one for listening

The bad part is that I don't have any testing equipment to do serious tests. The least I can do is get a general feel for their sound character.

[capslock]

If you find out they have them and will also give you pricing, let me know. Anything I order by early next week I can still pick up on my trip.

[TacoD]

@ Jon

Do you have any idea why the US GSM frequencies are around 1900 MHz? One should think in a country with this low a population density, lower frequencies would give you a better coverage for the same number of base stations.

In Europe, where it was developed, GSM started out at 800 MHz, and when they ran out of frequencies, a second band was opened at 1800 MHz.

The first two phone companies to start nationwide service in Germany used 800 MHz (called D net, A, B and C being previous generations of analogue mobile systems), because there was nothing else. The next two companies had to use 1800 MHz (E net). When dual band phones became common place about five years ago, our equivalent of the FCC allowed companies to swap frequencies. E net is now used by all four companies mainly in cities, whereas D is very popular for rural areas.

Greetings,

Eric

Audiocomponents only deliver cheaply to countries without a dealership. I called audiocomponents today, and they have the Peerless 18cm and 15cm exclusive on stock. I also want a pair of those, but I am coping Jon, only buying drivers without the time for building. (I've first to finish another AudioTechnology/ Skaaning project).

[goskers]

I went ahead and ordered a hds exclusive 830883 on Friday. I will be interested to see how it sounds compared to a rs180 in an open air environment.

[capslock]

I went ahead and ordered a hds exclusive 830883 on Friday. I will be interested to see how it sounds compared to a rs180 in an open air environment.

Still not in their online catalog. How much are they?

[goskers]

They are going for 69$ or so a piece.

[JonMarsh]

They are going for 69$ or so a piece.

That sounds about right- my 884's worked out to about $79.

If Mad has some of the 883's, I'll have to order some next month. Too much other stuff going on at work right now, plus travel coming up again.

~Jon

[JonMarsh]

Audiocomponents only deliver cheaply to countries without a dealership. I called audiocomponents today, and they have the Peerless 18cm and 15cm exclusive on stock. I also want a pair of those, but I am copying Jon, only buying drivers without the time for building. (I've first to finish another AudioTechnology/ Skaaning project).

Taco, you shouldn't copy my BAD habits!

Sometimes I think I do things like that just to motivate myself and hold out the possibility of a future reward- there was a time I was into computer gaming, especially flight sims, and would buy them when the one's I was intersted in came out... after having 3 or 4 on the shelf that I hadn't had time to do anything with, I realized I should rethink my evil ways.

Fortunately, with speakers, there's no such practical behavior on the horizon. I'm sitting on literally thousands of dollars of drivers purchased for projects I haven't had time to start. That, and 12 weeks of accrued vacation. 8O

I hear my new boss-to-be also wants to talk to the folks in our group about balance of work/life issues this week. I suspect he'll get an earful... :B

~Jon

[Paul H]

I hear my new boss-to-be also wants to talk to the folks in our group about balance of work/life issues this week. I suspect he'll get an earful... :B

~Jon

It's promising that the new boss wants to talk about it ...

Paul

[goskers]

Jon,

Does this mean that you have ordered some of the 884's?

What does you gut feeling say about the overall clarity between the new peerless offerings and metal cones like mag and aluminium?

How soon before you could do some testing on these?

Thanks,

goskers

[JonMarsh]

I've got four of the 884's, purchased from Solen, arrived about a week ago. Due to work obligations, no chance to test yet- so much travel, and working for commitments on papers on the weekend. I've got my fingers crossed, due to the low inductance rise and nice FR plots. Also have a nice open back.

I want to order some 883 and check them out in September. They'll probably wind up in the X1-SLAMM upper modules for testing and evaulation. I want to update the Eton's in there, and it's either going to be the 883's or RS180's.

Yeah, Paul, it will be interesting to see how the next couple of days pan out. My boss to be is divorced himself, but with kids, so he needs to make time for a personal life, also. When he visited our group a few months ago, he couldn't believe we had so few people vis a vis the ongoing activities. Gotta see what happens.

Some other things in the air, too, which could have an impact on various issues, like where I"m located.

[goskers]

Just did some listening tonight between the 830883's and RS180's full range, open air. I fully prefer the RS180's. The 883 had more detail in certain midranges but overall the clarity, naturalness and air was much better with the RS180. Take this for what it is as I did no actual tests. I will be sticking with the 180's for my array :T

[TacoD]

I would use a low-pass filter, because a metal cone sounds "airy" due to its ringing.

Taco

[JonMarsh]

Just did some listening tonight between the 830883's and RS180's full range, open air. I fully prefer the RS180's. The 883 had more detail in certain midranges but overall the clarity, naturalness and air was much better with the RS180. Take this for what it is as I did no actual tests. I will be sticking with the 180's for my array :T

I've known several people who like listening to drivers "au naturale" and use this as the basis for choosing which to use in a project.

I figure some of these guys probably read "The Absolute Sound" and enjoy their style.

Me, I'm more of a "Stereophile" type of guy, and I appreciate John Atkinson's detailed technical reviews- they help me correlate the subjective comments with objective data that I have some experience with and opinions about, even if I don't agree always with John's interpretation of the data.

So, I look for some specific technical characterisitcs and the possibility that I can minimize the driver signature in the area I want to use it in.

~Jon

[goskers]

If I had some good way to do driver testing then I would certainly partake in meausrements to support or deny a certain stance.

On a little seperate account, in terms of a midwoofer choice for a line array what would be more important in keeping distortion to a minimum, a great cone design or great motor design? Arrays have the ability to limit excursion so driving a cone out of it's linear range should not be an issue.

Jon, it would be great if you could find some time to do some testing on the new peerless offering. Heck, I'm sure if you had it you would, right?

Thanks guys.