Problems with metal domes

[kgveteran]

What do you think (oh, great XO designers) would make a metal dome tweeter sound bad ?

Besides a bad sounding dome to begin with, is there a XO "no-no" to look for when looking over two or three designers.

I have liked textile domes and soft domes since I began years ago. Hale Audio had a way of making them sound less like "metal".

When I sold B&W years ago I found their Matrix 801 had that "metal dome" sound, and never cared for them, and they were mated with Krell mono amps with Krell electronics.

Thanx KG

[Dennis H]

I think, more often than not, the "metal dome" sound comes from the midrange, crossing it either too high or not steep enough so the breakup modes aren't suppressed enough.

[cotdt]

some of the newer metal domes (like RS28A) doesn't have the metal sound, so i think it's the high odd order harmonics that create it. breakups can also contribute to that sound, which i'm sure of since i've done listening tests.

i also agree with dennis that crossing too low is the usual culprit, but some harsh-sounding metal domes have high crossover points like 4kHz so I'm thinking something else may be involved here as well.

[Dennis H]

i also agree with dennis that crossing too low is the usual culprit

Actually, I said the opposite. The midrange driver is often the problem, not the tweeter.

[kgveteran]

some of the newer metal domes (like RS28A) doesn't have the metal sound, so i think it's the high odd order harmonics that create it. breakups can also contribute to that sound, which i'm sure of since i've done listening tests.

i also agree with dennis that crossing too low is the usual culprit, but some harsh-sounding metal domes have high crossover points like 4kHz so I'm thinking something else may be involved here as well.

Do you think that variations in response, when it comes to tweeters is more critical than XO point.In other words, if a tweeter has the ability to reproduce levels up to 90db without breakup, any peaks within its frequency band could cause breakups at or about 90db.

If there is a 3-4db peak in the response, just like a room mode with subs it may keep that driver from performing at a higher level of sound...

[cjd]

I agree with Dennis on what is probably the most common "metal tweeter" fault, though, of course, it is far from being limited to metal if it's a midrange issue.

Additionally, some people (myself included) seem to have sensitivity to higher frequency (above 18kHz) breakup and/or harmonics issues that are more dramatic (for lack of a better word at the moment) on a metal dome tweeter.

The best way to try to understand the issue is to experiment.

C

[Landroval]

Uh, I can't agree with Dennis here. If you have two speakers with the same midrange and one with metal dome tweeter and the other with textile dome, the difference can't be from the midrange. I agree that sometimes harshness is caused by breakups of the midrange, but that's not the same thing as harshness of metal dome tweeter.

I've heard very few commercial metal dome tweeter equiped speakers that I have liked, so maybe I'm just not a friend of those. My current mains and center have metal domes (Seas coaxial) and these are close to the best I've heard. The old B&W 801 was bad, the Amphion Krypton worse and some top of the line KEF Reference was simply horrible.

[AJINFLA]

Kgveteran,

rather than debate whether this metal dome sounds better than that or some soft dome,etc, let me simply ask you this. When is the last time you listened to a live, unamplified drum set, playing by itself, no other instruments? Do you hang out around drummers or play the drums yourself on a regular basis? Are you intimately familar with the sound of ride/crash cymbals and high hats? Can you describe the sound? Can you tell me what soft dome accurately sounds just like this? Remember now, the live crash of a drumstick striking a cymbal. Thanks.

cheers,

AJ

p.s. I would want it to be a requirement for any DIY event to have instruments like a drum set and acoustic guitar present to a) remind us we are listening to recorded music on our speakers b) insert some reality into the proceedings as to "accuracy/detail/dynamics/etc". Would be interesting to see how fullange drivers, soft domes, floppy cones, 5" woofers, etc. fared.

[kgveteran]

I have to say that a number of years ago I did some sound reinforcement gigs with a good friend.One of my other friend is a drummer.I always enjoyed dialing the drummer first.Probably because I enjoyed the bass sound.Then the bass player,then the rest of the band.

I guess what draws me into a metal dome ultimatly is turning me off.The razors edge clearity at lower volumes seems to grate on me at higher volumes.I'll deal with this issue more with the XO designer than in this thread.

I think you have a point about softdomes.My last monitor seemed to give me the same sound on all recordings.That is good and bad.It made bad recoerdings bareable and great recordings sound just good.I'm finding now that all recordings (DVD,CD) sound very different from one another.Even vocals on movie soundtracks sound different.Here is an example.One moment a person sounds like he is on the movie set and very normal, next scene he sounds like an overdub in a well insulated recording studio.I like to hear these things, but without the edge.

[cotdt]

I've experimented with small peaks and dips in the upper octave, and I don't think it matters. But breakups are still audible even up high. Maybe it's not the peak but the distortion I don't know. The room response actually makes the tweeter sound smoother, since outdoors my speakers (the tweeter) sound thinner but more detailed in that notes are more clearly separated.

Have you tried the RS28A yet? I think you'd be surprised by how smooth it is, while it is also very detailed. The Seas H1212 is also very smooth but I think the RS28A is the smoothest of the metal domes.

Metal cones, on the other hand, still sound edgy to me when it comes to the upper midrange. Seas Excel Magnesiums, Dayton Reference, Seas L-series, and I think I heard some others too I don't remember, but they all have an edge to them that brings the music up front. They are smooth and edgy at the same time, I don't know how to describe in words! But soundstage is less wide than paper or poly cones.

[cjd]

But soundstage is less wide than paper or poly cones.

You sure that is a function of the material and not the transfer function?

I am actually planning a test setup with the intent of being able to sample different slopes on the same driver set - all fully implemented passive. I'm hoping to pull off a "warm fuzzy" vs. metal comparison too. We'll see how long it takes to materialize.

C

[kgveteran]

I'm sure doing tests could put an end to some of the vauge statements I have brought up.There are valid points, but without some numbers to back it up or be able to show it, it sounds more like opinions and not facts.

Our ears don't lie, its just better to bring up valid measured results.

****How about a lowpass filter.If I centered it on a PEQ at about 20khz and made it real broad, then cut it about the amount of db to reach my current sad 14khz threshold.That may take care of any breakups that may be occuring up higher and causing distortion in my audible range of hearing.Just a thought.

[peterS]

I think, more often than not, the "metal dome" sound comes from the midrange, crossing it either too high or not steep enough so the breakup modes aren't suppressed enough.

decay times is also an issue

[Brian Bunge]

IIRC, Jon has stated a lot of the "spitty" sound you get from many metal dome tweeters is due to the phase shield that many manufacturers use to help flatten the on axis response. That is why, whenever possible, Jon removes the phase shields on metal dome tweeters that he uses.

And I agree, the RS28a is just about the smoothest metal dome I've ever heard.

[cjd]

Our ears don't lie, its just better to bring up valid measured results.

They don't, but our brain often does a poor job translating *what* is heard accurately.

A filter is sometimes done but changes other aspects of a driver's behavior.

If you are having issues, a good place to start may be a full spectrum test of your hearing. See what you're working with, you know?

C