world's best coaxial driver?

[unknownuser]

All,

I was considering building some extremely nearfield speakers for monitoring purposes and am pretty intrigued by the concept of using a coaxial speaker to keep from having phasing problems between mid and tweeter. Apart from the Seas poly cone model (H1333 I believe), is there anything of higher quality available to the DIYer, of say scan speak level of quality? I really liked the sound of a few Thiel speakers I've heard, but don't know what the definitive diy offering is.

Thanks in advance,

Brent


(Originally posted by: gtwildwest)

[davidld]

This is an application where a pair of $50 Best Buy Insignias might work quite well, as they have a coaxial design. The only problem is that this is too simple and way beneath your budget. A great $50 experiment, tho.
Or a custom modded pair using one of the alternate crossover designs floating around for these from Dennis Murphy or GR Research.

> All,

> I was considering building some extremely
> nearfield speakers for monitoring purposes
> and am pretty intrigued by the concept of
> using a coaxial speaker to keep from having
> phasing problems between mid and tweeter.
> Apart from the Seas poly cone model (H1333 I
> believe), is there anything of higher
> quality available to the DIYer, of say scan
> speak level of quality? I really liked the
> sound of a few Thiel speakers I've heard,
> but don't know what the definitive diy
> offering is.

> Thanks in advance,

> Brent

[unknownuser]

For starters, I resent your budget comment and enjoy quality speakers regardless of price and brand. That much said, for this application I really do want the highest quality possible and am willing to splurge. Given what I've heard about Seas drivers and the measurements I've seen for them, I've got to believe the Seas would be an excellent option. In regards to the insignia, I've never heard them but have seen the measuremements on the Zaph Audio site and while they look great for $50 I don't think they will cut the mustard for hifi:

<A HREF="http://www.zaphaudio.com/Insignia.html">http://www.zaphaudio.com/Insignia.html</A>

Brent

> This is an application where a pair of $50
> Best Buy Insignias might work quite well, as
> they have a coaxial design. The only problem
> is that this is too simple and way beneath
> your budget. A great $50 experiment, tho.
> Or a custom modded pair using one of the
> alternate crossover designs floating around
> for these from Dennis Murphy or GR Research.



(Originally posted by: gtwildwest)

[gordoncalder]

Hi,

This might be the sort of thing you're after. I think he custom builds the driver though, so it may not be for sale (outside of buying one of his designs). I guess you could contact him and ask. Check out this link.

<A HREF="http://www.nomad-audio.com/design_foundations.htm">http://www.nomad-audio.com/design_foundations.htm</A>

Gordon

[davidyohn]

Provided Link: PA Audio


PAudio coax speakers sound pretty good and are very efficient as well.

<A HREF="http://www.commonsenseaudio.com/paudio.html">http://www.commonsenseaudio.com/paudio.html</A>

> All,

> I was considering building some extremely
> nearfield speakers for monitoring purposes
> and am pretty intrigued by the concept of
> using a coaxial speaker to keep from having
> phasing problems between mid and tweeter.
> Apart from the Seas poly cone model (H1333 I
> believe), is there anything of higher
> quality available to the DIYer, of say scan
> speak level of quality? I really liked the
> sound of a few Thiel speakers I've heard,
> but don't know what the definitive diy
> offering is.

> Thanks in advance,

> Brent

[dlr]

Don't over-estimate the Seas units. With the exception of the 1K woofer resonance (that can be largely fixed), the Insignias are probably the equal of the Seas. The problem is the basic design for both. I would describe neither the Seas nor the Insignia as best of anything. Well, maybe best bang-for-the-buck in the case of the Insignias.

I have not heard TAD, but I suspect that the TAD drivers would be contenders, though they may be too small for a 2-way and would be way on the expensive side. Same for the Thiel drivers. You'd need a 3-way to get the bass response as well, but it would be doable given the low crossover point from woofer to mid that could be used.

The newer KEF drivers are improved, I can't vouch for the 2-way versions sound, however. I have a pair of their 6.5" true midrange coax drivers, just haven't had time to do the XO yet. These would also require a 3-way setup. For near-field monitors, a new version of KEF 2-way might be the best way to go.

dlr

[filmboydoug]

Find a pair of vintage altecs.

I really do want the highest
> quality possible and am willing to splurge.

[unknownuser]

Have you heard the Seas before? Just wondering why you would have doubts about the quality. I admit that amongst their product offerings these appear cosmetically to be on the lower-end, but I'm still curious. For 50 bucks I might try the Insignias for surrounds, but I still agree with Zaph that on the basis of measurement these represent a good value for 50 dollars and do not approach an ideal solution. Are TAD or Thiel available for purchase? If only as replacement drivers then yes I would expect them to be quite expensive!

Brent

> Don't over-estimate the Seas units. With the
> exception of the 1K woofer resonance (that
> can be largely fixed), the Insignias are
> probably the equal of the Seas. The problem
> is the basic design for both. I would
> describe neither the Seas nor the Insignia
> as best of anything. Well, maybe best
> bang-for-the-buck in the case of the
> Insignias.

> I have not heard TAD, but I suspect that the
> TAD drivers would be contenders, though they
> may be too small for a 2-way and would be
> way on the expensive side. Same for the
> Thiel drivers. You'd need a 3-way to get the
> bass response as well, but it would be
> doable given the low crossover point from
> woofer to mid that could be used.

> The newer KEF drivers are improved, I can't
> vouch for the 2-way versions sound, however.
> I have a pair of their 6.5" true
> midrange coax drivers, just haven't had time
> to do the XO yet. These would also require a
> 3-way setup. For near-field monitors, a new
> version of KEF 2-way might be the best way
> to go.

> dlr



(Originally posted by: gtwildwest)

[damkor]

Coaxial is only one type. Supravox, Triangle, ATD, Fostex, Jordan, T-B, Bandor, Lowther, Adire and others make full range drivers. There is also the Morel Integra. Cabasse make a tri-axial. Here is the B&C site, they make the priciest coaxial driver, for PA.

<A HREF="http://www.bcspeakers.com/">http://www.bcspeakers.com/</A>

[Wolf]

They offered a 3 or 4 way coax driver, that is concentricly operational. I *think* it was the "TC21"? Not sure it's still available.
Later,
Wolf

[dlr]

> Have you heard the Seas before? Just
> wondering why you would have doubts about
> the quality.

I have not heard them, but I'm told by someone I trust who has used them that they have a similar sound to the Insignias. Also, the published curves show a strong similarity to the Insignias. This is based upon the driver geometries (woofer and tweeter). They both have woofer horn loading issues. KEF has improved on this significantly in recent years.

Zaph also pointed out that they hold up to other similar drivers in distortion testing.

> I admit that amongst their
> product offerings these appear cosmetically
> to be on the lower-end, but I'm still
> curious. For 50 bucks I might try the
> Insignias for surrounds, but I still agree
> with Zaph that on the basis of measurement
> these represent a good value for 50 dollars
> and do not approach an ideal solution.

They are definitely not ideal.

> Are
> TAD or Thiel available for purchase? If only
> as replacement drivers then yes I would
> expect them to be quite expensive!

I don't know about TAD, but I think that Thiel drivers may be available. The price is way out of my pocketbook for what they are. If price were not an issue, I'd pursue them.

dlr

[dlr]

Zalytron lists one current and 2-3 closeout sale drivers that are coaxial by PHL. Pricing is competitive with Seas for a 6.5". I have no idea as to qualities of them. They don't even have a catalog with some pics in them.

dlr

[Jeff B.]

[ajinfla]

Provided Link: TAD/Pioneer Beryllium tweeter /Magnesium mid


..such as "worlds best" >insert driver or widget or whatever< here.
If you want a very high performance coaxial the way a high performance coaxial should be designed, try these (link).
You will need a woofer for bass frequencies (as you should).
And yes, that price is *each*.

cheers,

AJ

[ajinfla]

Kinda forgot that I had found a few spare minutes the other day to do a quickie on the JBL's. Tweeter only, no DSP (I'm going to go outside to measure the mids using RTA for now, since they are going to be dipole. I'm really measuring the baffle & driver simultaneously).

How are the KEF's?

cheers,

AJ

[dlr]

> ..such as "worlds best" >insert
> driver or widget or whatever If you want a
> very high performance coaxial the way a high
> performance coaxial should be designed, try
> these (link).
> You will need a woofer for bass frequencies
> (as you should).
> And yes, that price is *each*.

I thought that you'd have a line array using them by now.

Actually, I like the idea. Too bad I'm not independently wealthy.

dlr

[dlr]

nt

[unknownuser]

> I thought that you'd have a line array using
> them by now.

actually, a line array of coaxials would have the treble source points way too far apart.


(Originally posted by: George K)

[dlr]

> Kinda forgot that I had found a few spare
> minutes the other day to do a quickie on the
> JBL's. Tweeter only, no DSP (I'm going to go
> outside to measure the mids using RTA for
> now, since they are going to be dipole. I'm
> really measuring the baffle & driver
> simultaneously).

> How are the KEF's?

I haven't had time to do a XO. I started before DIY NE, but the tweeter is a bear to work with passively. They measured nearly identically to the supplied curves raw, but the extreme peaking of the tweeter at the knee is a lot harder than I had thought it would be. Too high a Q with a too-high delta above nominal.

The driver-to-driver consistency is superb. This from a pair that had the tweeter domes dented all over. I was able to work them back out slowly. Most evidence is not gone that they had been dented. And I got the pair for $40 + shipping!

I plan to get back to them soon as I'm now putting the second one into a box. It drops into the Insignia perfectly except for the baffle cover. The back side relief will only need a small amount of routing to allow it to sit flush on the KEF driver.

dlr

[dlr]

> actually, a line array of coaxials would
> have the treble source points way too far
> apart.

Depends on the overall driver diameter, listening distance and crossover point. The TAD is, I believe, not a typical 6.5" coax. I think it's more like a 4.5" or 5". If you had a roughly 5" CTC crossing at 2K it would be a workable alternative. It also would significantly reduce the horizontal off-axis issues.

Add into that the fact that the dispersion of a coax provides a more uniform transition from woofer to tweeter thus a more uniform power response and the problems/issues become much more complicated.

Certainly a line of small dedicated tweeters allows for better on-axis response in the vertical plane, but the off-axis issue of offset and horizontal lobing may be worse.

Add in a decent listening distance needed for line arrays, especially longer ones and I think that the problems associated with this kind of array would be much less pronounced.

As in all things speaker related, it depends.

dlr