Home audio loudspeaker - 8"/10"/15" Coaxials crossover at 1000Hz

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Member
Joined 2009
Paid Member
Mayhem,
It seems to be a pattern in the way to (we think how to) use coax (to their optimum)! :)
I never used my Tannoy like Earl described. I will try that when time allow!
Isn't a Danley Sound Lab product you are talking about? I remember seeing one model with a relatively large coax inside a ( kind of) waveguide from them.
That said i think to have read a thread here where most said it wasn't a good idea if my memory serve... i'll search about that.

Zvu, i never had a chance to listen 'in real' to Kef's Uni Q drivers. I've listened to comparison Mitchba have on his site however. But it is not like real life experience of the thing imho ( as both the Ls50 and his own system are eqed to be equivalent).
Let us know what you think of the Tymphany when you got it!
 
Last edited:
KEF LS50W and KEF Q100

@Zvu

This morning, after uploading an image of the spectral decay of the KEF LS50W I wrote:

index.php


[Video] Speaker measurements by Danny Richie | Audio Science Review (ASR) Forum

Now, I can say again: I LOVE my modded KEF Q100 5.25" coaxial speakers!!!!

With three slightly touch in the frequency graph from JRMC 64-bit the sound is still better.
At 40 Hz, 1400 Hz and 1700 Hz.

Using as reference your measurements, for which I am immensely grateful.


KEF-Q100-fabricka-zvu.png

-> [IMG, link] http://maty.galeon.com/WP-imagenes/kef-q100/KEF-Q100-fabricka-zvu.png


KEF-Q100-modifikovana-zvu.png

-> [IMG, link] http://maty.galeon.com/WP-imagenes/kef-q100/KEF-Q100-modifikovana-zvu.png
 
Last edited:
......

Zvu, i never had a chance to listen 'in real' to Kef's Uni Q drivers. I've listened to comparison Mitchba have on his site however. But it is not like real life experience of the thing imho ( as both the Ls50 and his own system are eqed to be equivalent)....

Mitchba listened to factory crossover LS50 which i consider not to be tailored for accuracy. Although it doesn't sound bad in regard to other factory loudspeakers, the drivers have lots of potential for upgrade by proper crossover. Let alone by adding a woofer bellow 150Hz to take over the bass duty.


......Let us know what you think of the Tymphany when you got it!

Will do :)

@Maty - Danny Richie obviously messed it up in that measurement as CSD from John Atkinson shows a much cleaner picture:

KEF-LS50-spectral-decay-x2.png
 
Spectral decay of KEF LS50W is from a PDF of HifiCritic. I could not believe the waterfall. Except to align the frequency response, what improvement is the DSP doing? Well, you can also align the phase optionally.

PDF from Hificritic:

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwielfrTpb7kAhWN4YUKHf8yCVsQjhx6BAgBEAI&url=https://oslohificenter.no/streaming/aktive-hoyttalere/kef-ls50-wireless?iid=396959&pid=OHC-OHCProduct-ExternalReviews.OHC-PageLink-FileLink&psig=AOvVaw2Km2sg6JNc0IG6yCapST_g&ust=1567930818915069

Danny measurements appear only in the video and comments two and three.
 
Member
Joined 2009
Paid Member
Mayhem,
The waveguide loaded coax i was thinking of are DSL SM100 and SM80.
Are they the one you were talking about?

Qts,
Because they are a possible choice ( despite the fact that they are not available to end user as spare parts if i understood correctly edit: crossposting with Zvu ).
With the revival of coax in proworld in past years ( Genelec, Presonus,...) and in hifi ( TAD) this is solutions that may give very good results if correctly implemented ( read not mass produced items).
Worth mentioning them in my view.
 
Mayhem,
The waveguide loaded coax i was thinking of are DSL SM100 and SM80.
Are they the one you were talking about?

Qts,
Because they are a possible choice ( despite the fact that they are not available to end user as spare parts if i understood correctly edit: crossposting with Zvu ).
With the revival of coax in proworld in past years ( Genelec, Presonus,...) and in hifi ( TAD) this is solutions that may give very good results if correctly implemented ( read not mass produced items).
Worth mentioning them in my view.

Very similiar but a stage monitor and the waveguide transitions to rectangular in what looked like (by memory) an 80x50 pattern control or thereabouts. Still can’t remember though!.......
 
As a test, I once built a coax based on a B&C 10", I believe. To KISS, I made it a dipole on an open baffle. I was amazed at how good this could get for a speaker system which cost almost nothing (no box to build, a somewhat complicated crossover, but all-in-all quite inexpensive.) Trouble was of course that it had no bass response at all. If one were to do this with multiple subs I bet that you could build a great system.

Coax can never be quite as god as a separate waveguide system, but the later are so much more difficult and expensive. For value, the coax wins out.

Generally speaking the narrower the directivity the less negative effects the room will have on their perception, but it depends on the room, of course. Directivity is irrelevant in an anechoic room, but all important in a reverberant one. Home listening rooms tend to be all over the map with European construction being clearly more reverberant than typical US construction. But high directivity is never really detrimental, it just gets a lot harder to achieve as one goes narrower and narrower.

Thank you for your response. I will check out some B&C drivers. Where can I buy a oblate spheroid waveguide? I have heard some 80x50 waveguides and they result in stumpy singers (6 feet tall signers sound like dwarfs)
 
Hello Earl,
Yes i'm sure a multisub + coax will give great results. Even better if like you discribed in the '2 way high spl...' thread: as wideband as possible mains + mono multisub.

Swara,
Earl gave one important point in his answer: x over can be troublesome with coax.
That's why i didn't talk about passive but active dsp solution for your case. The electrical part of x over usually are asymetric for coax with something typically like 12db or 18db lp for woofer and 6db hp for CD.
Other options are possible but passive is usually like that. Sometimes you could find allpass cells used too.
This is related to the fact that emission points of both drivers are not always coincidents: direct radiator may be 'in advance' related to the CD ( iow the direct radiator is located 'in front' of CD emmission point). One other sneaky point is that emmission point 'move' with frequency, but with coax this is limited as directivity must match and 100hz difference shouldn't be dramatic difference.
This is not always true but it happend: my System 800 are the passive version and Tannoy didn't adress this issue with this one which is not the case with the active version.

I know because some mix/works i've done with active sound 'weird' with my passive around 1,5k which you probably have guessed is around the xover point (1,6khz from Tannoy doc).

With a dsp solution i could probably fix that using a delay ( a allpass filter is a passive equivalent to a delay- up to a limit). Passive this is hopeless as i should have to rebuild xover from scratch and i don't find this either funny or easy ( i'm a lazy dsp guy :) ).

B&C drivers are GREAT drivers, their coax too i agree with Earl about that too.
Swara have you seen Seaton Sound offer?
The Catalyst is a great example of what could be done: 8" B&C coax + 2x12" sub in mtm dsp driven with classD amp.(edit: he added a new catalyst with 8" subs. Probably from Acoustic Elegance like most sub he use).
The latest TAD effort are worth a look at too: 6,5" ( or 8" idon't remember) coax + 2x 8" (or 10") in a TMM form factor ( making it a 3,5 way).
(edit: just checked: 6,5" and 2x 10". This seems to be approximately the same balance of cone area as seaton's sound between coax and sub drivers. This could be a 6,5" and a 15" too and i bet it could sound even better this way than with 2x10").

Both are great source for inspiration imho.

Swara two other questions: what is your ceiling height? And what are your main source?
The height is to determine overall volume of your room ( and thus have an idea of the membrane area you'll need for sub) , the source is to give you hint about what could work for dsp filter solution.

One last thing: you should go to Earl's site and read the whitepapers! Lot of knowledge and practical answer to reallife issue to be gained.
I expected the passive crossover to be complex. I was more concerned about the phase than a slightly wavy frequency response.

I will check out the Seaton Catalyst loudspeaker.

My ceiling height is 9ft and my source is a laptop with Roon as the audio player.
 
Member
Joined 2009
Paid Member
Hi Swara,
Ok your room is about 50m3 volume so from my experience i would not use too big drivers.
My take on this ( which is from experience and my guts feeling nothing i can point to research or science related background) is if you ONLY RELY on mains's drivers for sub don't use more than 12".

I think there is a point at which you start to 'overpower' your room with too much energy in the bass with 'big' drivers. And you face the issue of room placement, which may be perfect for the medium high but excite room mode too much (for example). If sub is on the mains's box there is not much that can done in that case ( except going multi sub).

With a modular approach to box this can be minimised.
An other approach is to go MTM or TMM as it is a crude ( and simplistic) approach to a distributed bass. For this you can downsize driver size ( eg: 2x12" is more or less equal to 1x18" membrane area, 2x10" to 1x15", etc,etc,...).

This is one approach which may be convenient... or not! And i expect to be corrected (or not) in my view of this. :)

About filtering ok you run a computer as source.
Here again there is multiple options here is one: invest in a multiple output good quality soundcard ( or a combo multiple digital output card + multiple D/A converters) and use a software for filter duties.

Something dedicated as Accourate or similar soft for filter and keep your already known player.
Or go JRiver which could integrate player and treatments in a single software. And use Rephase to make your filter profile which are then used to process your drivers 's way.

This way you can use amps tailored to drivers and overcome efficiency difference ( something like low watt high quality class A amp for mid/high and classD monster power for low as example). Once in multiamp dsp, efficiency differences become moot imho ( not totally but much less an issue).

And if you are interested in FIR filters and a bit of 'dsp room treatments' this is still an option.
 
Last edited:
Hi Swara,
Ok your room is about 50m3 volume so from my experience i would not use too big drivers.
My take on this ( which is from experience and my guts feeling nothing i can point to research or science related background) is if you ONLY RELY on mains's drivers for sub don't use more than 12".

I think there is a point at which you start to 'overpower' your room with too much energy in the bass with 'big' drivers.
I don't see that opinion as very valid. The size of the source does not dictate the amount of LF energy put into the room. Size does determine how low in frequency one can do that and, for my money, bigger is better even in a small room. My HT is a pretty small room and I have 4 15s and 2 12s. three are subs and three 15s are in the mains. That's a lot of very big drivers in a small room and it yields excellent bass with lots of headroom. I think that bigger is always better if you have the room for it.

I think there is not too big drivers. I think it is where room modes are compared to frequency response of the speakers. If they are low enough, where response is going down, they are less harmful.

Think of it this way. The room modes will never be "low enough" to not cause problems, except in big rooms. So the LF solution has to deal with this problem. In the modal region, the room dominates the situation, which means that the speakers response is a secondary issue. Using multiple subs and LF EQ is, IMO, the only universal way to deal with the LF mode situation.
 
Member
Joined 2009
Paid Member
Sorry Qts, i don't get your second sentence in post #32.

About coaxials i agree higher diameter have lower control on directivity and this is 'better' than smaller one ( i already stated this in my first post).

My comment was about Sub/ low way in a three way configuration, not a case of 2way coax.

Earl, i was sure we were going to not agree on this. It is difficult to explain this clearly in english as is ( it is a foreign language for me) so i will need some time to formulate my observation about that but i'll do in following post.

For now the thing i can tell you easily and for sure: i live with a 'big' ( more medium sized to me but related to today's standard 100liters is 'big') three ways with 15" ( 38hz to 750hz, 5" mid up to 4,5khz, 1" tweeter) for nearly 25 years now and they followed all my journey in very different place : from student flat of 20m2 to my now main room which is almost 200m3 - 50m2 floor plan with sloped ceiling up to 4meters a bit leaky relative to bass, more in line with US standard room for this part of spectre.

There is no competition: this is the first time i'm not struggling about low end for them. All my previous places had issue with bass and mode with them. This was not the case with my other monitors which have ( had for the ones i don't belong anymore) smaller diameter drivers ( within same bandwidth of around 40hz and i listen with calibrated levels which follow K-20 but instead the 85db reference level this ranged from 75 to 82 dbspl in the different rooms i had).

Multitask: 50m3 NOT 50m2. ;) Swara told 5m x 4m x 2,7m: around 50m3. This the volume which matter in my view.
 
Last edited:
\my method has always been 3 way and NOT have the cone move at all to keep the intended waveguide properties as stable as possible, and that's using an 8" coax crossed in the 250hz range steep filter.
I've been doing this for about 20 years. I did it first with Tannoys of all sizes and every time I mentioned it to a Tannoy diehard, you could actually hear the pearl clutching even from overseas.

My current surrounds are Faital 8HX200 and AE TD15X, DSP active with xovers at about 300 and 1k7 IIRC, both LR24. I'd be happy with them as mains. The Faitals measured pretty close to the datasheets too.
 
I've been doing this for about 20 years. I did it first with Tannoys of all sizes and every time I mentioned it to a Tannoy diehard, you could actually hear the pearl clutching even from overseas.

My current surrounds are Faital 8HX200 and AE TD15X, DSP active with xovers at about 300 and 1k7 IIRC, both LR24. I'd be happy with them as mains. The Faitals measured pretty close to the datasheets too.

How do find the quality of the your Faital 8HX200, the sound and the high freq horn and the and the mid-range driver? Does it come with the High freq. horn when you buy it or you buy separately?
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.