Midrange driver w/ good transient response?

Elbert

Member
2008-03-22 6:16 pm
Fellow audiots, I need some advise here..

I'm planning an active 3-way system using some old but good SEAS 13" 33 F-WB woofershttp://www.seas.no/images/stories/vintage/pdfdataheet/h172_and_179_33f-wb_and_dd.pdf

I intend to cross these over fairly low, leaving a midrange unit to cover the entire critical 200-2kHz range.

As for tweeters, I'm probably gonna go for the SEAS DXT units, as I find the dispersion control feature of these both novel and interesting.http://www.seas.no/index.php?option=com_content&task=view&id=184&Itemid=179

So, that leaves the midranges.... I realise there are no one perfect midrange, instead I'm hoping to find the optimal midrange for my intended application and design priority .

The use, I've more or less described.

Rather than obtaining perfect linear response and minimized distortion levels, I'm aiming for a design that can reproduce dynamic music with engaging transient response and detail at convincingly "realistic" sound pressure levels. loud and clear.

I've rummaged through previous posts and the web in general in search of greater midrange wisdom, but what i find is that most information is concerned with frequency response and harmonic distortion. Sure, a lot of interesting info here (in particular on zaphaudio.com), but I have failed to find much on how to identify midranges/ midwoofers likely to have good transient response.

Any suggestions to what criteria/ parameters to look for here, or in deed, any particular driver recommendations?

For their good quality (and some patriotic sentimentality) I do have a soft spot for seas drivers.

I have looked at a 5" SEAS midrange, the MCA15RCY
http://www.seas.no/index.php?option=com_content&task=view&id=102&Itemid=124
which seems to be designed specifically to cover the frequency range I'm intending to use. Also, I reason that 5" is a good size in terms of of axis response.

The SEAS ER18RNX http://www.seas.no/index.php?option=com_content&task=view&id=111&Itemid=133 has also been recommended to me as a good new design, made even more interesting by Zaph's comments and SR 71 application.

but then again, could some of the metal cone designs have any merit for my application?

Could 2 midranges per speaker have any advantages?

The Tangband W4-1337SA certainly looks sexy, at least on paper (except for the somewhat low efficiency and power handling)

Anyway, enough ranting, I will now humbly await guidance and enlightment from those knowing more than I do!:)
 

EspenE

Member
2003-06-13 9:01 am
Oslo
I cannot see how you can define "transient response" in one specific frequency range, as transients have components from all frequency ranges.

However, as to impulse response, power compression and ability to reproduce realistic dynamics there IMO really is no alternative to relatively large (8-10") prosound drivers.

Look at the JBL 2118 or 2123, or the 18sound and B&C midrange drivers.
 

Elbert

Member
2008-03-22 6:16 pm
Hi Espen,

Well, transient response, impulse response.. could well be I('m mixing up terms here, been a while since I messed around with audio projects!. But what I'm talking about is a snare drum that goes "SMACK!" in stead of "slapp" if you know what I mean...:D

Had a look at some of those drivers you recommended... Efficiency and power handling is awesome, which is rather common for PA speakers... but how do they really sound....?

Most PA type speakers i have listened to are just loud but more often than not more or less tiering and unpleasant to listen to... (unless you actually happen to be at a concert in a good venue where the sound technicians knows his stuff)

Sreten,

Those Gravesen speakers really look interresting! There certainly is an appeal to simple high efficiency systems like that. The almost minimalistic approach, perhaps with an element of "alchemy" thrown in.
Couldn't find any prices on the web page, but from the looks of it, probably rather expensive...

Well, this time around I'ts going to be an active 3-way, one day when i get a nice hose with a proper listening room I can start playing around with horns and high efficiency stuff again! :)
 
Elbert said:


Sreten,

Those Gravesen speakers really look interresting!
There certainly is an appeal to simple high efficiency systems like that.


Hi, you might be missing the point ...... , :)/sreten.

Compared to all other speakers I've made, the area where this
speaker differs the most is in its ability to reveal musical transients.
The speed and attack it can produce is something none of all the
other speakers on this website can manage. It's fast, very fast.

you do have a 96dB/W low bass unit .......
 

Elbert

Member
2008-03-22 6:16 pm
Sreten ,

I did get the transient bit, and that sounds familiar to what I experience with my voight-horned Corals for all their other flaws..

The more I read around the more I get the impression that there is some connection between high efficiency and good transient response... hmmmm...
 
Elbert said:
Sreten ,

The more I read around the more I get the impression that there is some connection between high efficiency and good transient response... hmmmm...
the more I listen to low or high efficient GOOD speakers, the more I get the impression that there is some connection between good speakers and good transient response. Some 83-84db monitor are amazing in this "transient" matter.


;)
 

Elbert

Member
2008-03-22 6:16 pm
Aaaah! The French, always so philosophical and convoluted! :D

But who am I to argue, it was after all some good Frenchmen that really taught my about the pleasures of GOOD wine and food! ;) They must be on to some thing... :)

So what is a good midrange then... must say I'm leaning towards the SEAS MCA15RCY, seems like Mr Gravesen were reasonably positive about these, and he seems to know his stuff..http://www.troelsgravesen.dk/PMS.htm
 

EspenE

Member
2003-06-13 9:01 am
Oslo
Elbert said:

Well, transient response, impulse response.. could well be I('m mixing up terms here, been a while since I messed around with audio projects!. But what I'm talking about is a snare drum that goes "SMACK!" in stead of "slapp" if you know what I mean...:D

Had a look at some of those drivers you recommended... Efficiency and power handling is awesome, which is rather common for PA speakers... but how do they really sound....?



Given the right crossover, good prosound drivers sound great. I have (and still use) nice systems with Seas W22, Seas 27TDFC, Seas Millenium, Peerless XLS, Scan-Speak 2900 etc. None of those systems can compare with systems based on prosound drivers when it comes to realistic dynamics, headroom and general ease of reproduction.

The snaredrum SMACK! you speak about has somthing to to with just that.
 
Elbert,
I don't want to go to the "best suited mid-driver" opinion, I would just advise you to decide what is your necessity.
At the moment you want to cross the mid relatively low (200Hz) you need "drive" in the low-mid range particularly if you cross your woofer with steep slopes. "Drive" at 200Hz...hum...you need some consequent SD so a 16 to 20cm should be more adapted than a 5". That's the first point and certainly the most important one. A 5" could be suffisant in this "drive" matter if you were going to use a large baffle as in the Troels PMS.
Than...transients (or in reality what you perceive as..): they do come VERY mainly from the global design of the speaker, NOT from one or more tech features of its drivers, at least not from those related to the T/S parameters except if drivers are working at Fs which isn't the case with a mid-driver. So looking at the distorsions curves isn't a bad thing. If you need high spl, than yes, PA drivers certainly should be well adapted. If you remain in the domestic hifi field, between the two SEAS you named, I would personnaly chose the ER18RNX, better low-mid drive, handles (directivity and distorsions issues) a 2Khz fr cut. Also, because of the type of woofer (no stiff cone) you still have, I would not look at the stiff coned mid-drivers.
But...I would personally chose the vifa XG18 as it seems to be particularly adapted to a 200-2000hz range, check Zaph's site if efficiency is enough for your design (or two of them).
My two cents. (
BTW, as a french but alsacian guy, I would advise a good "choucroute" + Rieling:)
 

Elbert

Member
2008-03-22 6:16 pm
Hmm.. undoubtedly a bit "controversial" this idea of using hardcore pro-speakers in a hi-fi set up, but not to be disconsidered I guess...

B&C and 18 sound apparently had some 6,5 inch midranges, the 6ND430 looked sort of interesting... But looking at those efficiency and power handling figures, there must be a tradeoff here somewhere?

Anyone else had any experience with pro/ PA drivers in HI-Fi systems?
 

Elbert

Member
2008-03-22 6:16 pm
Crazyhub,

I welcome your advice regarding driver size, selecting a midrange that would fail to deliver the punch in the lower frequencies would in deed be a bad move! The baffle will probably not be the smallest as I'm building boxes in the 120-170 L range, but i don't know if that will be of any help?

I have been looking at the ER18RNX, it seems like an interesting driver in many ways. According to my local SEAS supplier, it almost an excel driver for the price of a conventional prestige driver. Krutke also seems to be enthusiastic about this driver.

My main reasoning behind looking at the MCA15RCY, was that it is a dedicated midrange, and it seemed to have the correct recommended frequency range.
The ER18RNX is designed to have a very large Xmax, which I thought would be a redundant feature for midrange application, further reasoning that the extended X-max would be a tradeof or compromise of some sort not made in a dedicated midrange.

Regarding the XG 18.. well, it's made in China... probably an excellent driver, but I'd rather support what little quality manufacturing industry there is left in Europe (not to mention Scandinavia), so I'd rather buy my drivers from the Seas guys here in Norway if given the choice... ;) I have to be patriotic about SOMETHING since we don't have good wine you know... :) (or any wine for that matter..)

Ah.. never been to Alsache... your gastronomic recommendation sounds interresting, I do have a soft spot for the more rustic and hearty German inspired quisine as well. Tried "Eichbein"
last time I was in Germany, being served that pork joint of 1kg certainly provided for a subsrtantial Teutonic eating experience! :)

Looking at distortion curves, yes, Krutke certainly has lots of good info there, a bit harder to come by for the pro-drivers though....
 

BHTX

Member
2006-02-16 10:49 am
Elbert said:
Regarding the XG 18.. well, it's made in China... probably an excellent driver, but I'd rather support what little quality manufacturing industry there is left in Europe (not to mention Scandinavia), so I'd rather buy my drivers from the Seas guys here in Norway if given the choice... ;) I have to be patriotic about SOMETHING since we don't have good wine you know... :) (or any wine for that matter..)

Well if you're gonna get Seas regardless, get it then?

Elbert said:
Looking at distortion curves, yes, Krutke certainly has lots of good info there, a bit harder to come by for the pro-drivers though....

Beyma usually lists distortion performance on their spec pages. However, I don't care for their graphs much.. I think, at first glance, their drivers tend to look a little more well mannered than they are, due to the fact that the graphs are always so small. There's not much space between the 5 or 10dB steps on the graph. Regardless, most of them don't seem to be very smooth anyway. Perhaps often a little less smooth than some other competing pro drivers. On the other hand, I've always heard that those graphs they show are pretty truthful and dependable, unlike so many other manufacturers out there.

I believe JBL often shows distortion performance on their graphs as well.
 

Elbert

Member
2008-03-22 6:16 pm
BHTX,

Yes, as long as I stay within the domain of "traditional" Hi-Fi drivers, I'm pretty much inclined towards SEAS I guess..:D Of course, if there is a really compelling reason to chose otherwise, I might reconsider...

I have made similar observations to you, most Pro-driver graphs look less than convincing, both in terms of size and resolution and quality... Judging by the graphs, some of those units are bound to sound like 1930 Public Announcement horns only 20 times louder...:xeye:
 
Elbert said:
Crazyhub,

I welcome your advice regarding driver size, selecting a midrange that would fail to deliver the punch in the lower frequencies would in deed be a bad move! The baffle will probably not be the smallest as I'm building boxes in the 120-170 L range, but i don't know if that will be of any help?

Help will come from baffle sizes, compensating (or not) baffle step loss:
http://www.t-linespeakers.org/tech/bafflestep/index.html
 
Elbert said:


I have been looking at the ER18RNX, it seems like an interesting driver in many ways. According to my local SEAS supplier, it almost an excel driver for the price of a conventional prestige driver. Krutke also seems to be enthusiastic about this driver.

OK but relatively high H3 & H5distorsions in the midrange up to 1.7Khz...Will you be able to compensate with your active set-up?
BTW, the fr response (bump 1-10Khz) of the tweeter will also have to be shaped; this fr response due to the horn seems to help reducing the x-over slope/distorsions issues in passive filters, not in actives ones:
http://www.zaphaudio.com/hornconversion.html
 

EspenE

Member
2003-06-13 9:01 am
Oslo
Elbert said:
Hmm.. undoubtedly a bit "controversial" this idea of using hardcore pro-speakers in a hi-fi set up, but not to be disconsidered I guess...

B&C and 18 sound apparently had some 6,5 inch midranges, the 6ND430 looked sort of interesting... But looking at those efficiency and power handling figures, there must be a tradeoff here somewhere?


Not very controversial. Many threads on this forum deals with good use of such speakers. Do some searches on B&C, Beyma, 18sound or JBL (to mention a few).

Or read this thread (very long, but illuminating) as an appetizer: http://www.diyaudio.com/forums/showthread.php?s=&threadid=100392

The main tradeoff in prosound drivers is size. Big drivers and big boxes. I would not use a 6,5 inch midrange (given I had room for it). Better with 8" or 10". (Even a good 15" can be used for great results up to 1 kHz).

Another tradeoff is ultimate smoothness of frequency resonse. Generally, "hifi" drivers are better in this respect. But in my opinion this isn't a very important criteria anyway.

Being a fellow norwegian, I also like Seas units (and have used quite a few of them). As I remember, the Seas 33F-WB is a quite efficient driver, with a sensitivity of 93-95 dB/W. Don't waste all that good sensitivity with low-sensitivity midranges like the MCA15.
 

Elbert

Member
2008-03-22 6:16 pm
Well, don't know if the baffle will be big enough to help all the way down to 200 Hz though.. this will also depend on the final placement of the driver I guess...

Yes Espen, the 13" woofer is fairly efficient at about 93dB/w, but as I'm planning for an active system, adjusting the level between drivers is a possibility, and the 89dB/w sensitivity of the MCA5 isn't really that bad compared to numerous other hi-fi units out there.. Of course, it can not match the ear-melting figures of some of those pro-drivers!

10 and beyond sounds awfully large for a midrange, although I know that this is common in the sound reinforcement industry... I'm starting to get worried about directivity here....

but an 8" driver might be feasible though...

Some thread you posted a link to, guess I'll go get a beer and sit down for a good read! :)

By the way, what are the price for one of those better pro-midranges here in Norway these days??
 

EspenE

Member
2003-06-13 9:01 am
Oslo
Of couse: in an active system. matching driver sensitivities is not so much an issue.

I would not be too concerned over directivity on 10" and lager drivers, given that you can cross low enough. In fact, in most rooms more directivity that what is typically exhibited in a 5"mid +dome tweeter is beneficial.

Controlled directivity of about 90 degrees seems to work in typical rooms. This cannot be acheived with normal dome tweeters - you need some sort of waveguide (eq the Seas DXT, though this waveguide is much to small than to have any real effect below 3 kHz). Bigger waveguides is needed if you want to cross lower.

It makes good sense to cross the mid over in the frequency range where the mid's directivity matches that of the tweeter system. I have had good results with 6,5 inch waveguides crossed at about 2 kHz to 8" midranges. Or 12" waveguides crossed at 1,2 -1,4 kHz to 10 or 12-inch mids. As an aside: Together with waveguides, compression drivers give much better results than dome tweeters.

In my mind, good prosound drives in the right application makes most standard drivers (such as the ones previously mentioned) sound like toys. Agreed: this is another approach that the typical bass + 5" mid + dome hifi setup. But IMO this approach offers better opportunity for success given your starting priorities ("loud and clear", "realistic volume", "snare-drum SMACK!!").