Khorn midbass proposal

[Horatio]

It's been a while since I've frequented this forum, but, I have an idea I wanted to run by folks here:

I have used an EV HR9040A and HR90 in search of improved lower mid performance on my system (speakerlab bottoms with K33E's/crite's critters in the bottom). Love the HR9040, but it's enormous. Still doesn't quite fix the low mid end.

I have been looking at an RCF MR10N301, a 10" sealed back very high efficiency midrange, with a phase plug, going into a DDS DMB-10N horn. This looks like a combination that ought to work for 250-1.5K or so. This should make a serious run at that low midrange upper mid-bass area I've been after. I will have to figure out a good combo for the top with that, but the HR90 should do this without much trouble (whole thing is getting big again...).

Thoughts? Anyone use one of those DDS horns for this type of thing? The RCF unit is quite sensitive, and coupled to the horn should provide more than enough sensitivity with respect to the bass unit.

Thanks!

Mike

[Speakmeister]

Hi Mike,

I am not sure how low the DDS horn controls the polar response, do you have the specs on it?

I experimented with an EAW 4953 mid-range horn for a while. It is a horn loaded dual 10" cabinet. I crossed it at 300Hz with a Behringer DCX2496. I was very impressed with the performance. they were a little big to keep for a long term setup. also, I was able to turn the bass section of the klipschorn up with respect to the mid and top, giving the bass alittle more authority.

The great thing about using the 10" mid horn is you can choose a quality 1" compression driver crossed around 2K.

[Horatio]

Yes, the DDS horn has polars and they look pretty decent. It's a 70X60 coverage unit, 150-2K responswe horn (they recommend to use it 250-1.6K). The main thing that moved me to look hard again at that unit, is the RCF 10" driver: This is sealed back, and can be had with a phase plug. In a 90X 40 horn, this thing does 109 db for sensitivity (!).

I would think it is possible, with a good DSP, to tart up the upper end of the PWK bass unit to correct for the swinginess in the response, but it does not do anything for the phase response, nor the polar matching with the mid horn. The way to deal with this is to use a straight shot for the upper midbass/lower mid, with decent polar management, and then time align it with the DSP. Keep the bass as bass, and carefully work the upper end. At least that's the logic i'm following.

Short of finding a good pair of Emilar EC600's and decent matching horns, I don't know of a better way to attack this area. Packaging gets to be a real issue.

[greg928gts]

It's been a while since I've frequented this forum, but, I have an idea I wanted to run by folks here:

I have used an EV HR9040A and HR90 in search of improved lower mid performance on my system (speakerlab bottoms with K33E's/crite's critters in the bottom). Love the HR9040, but it's enormous. Still doesn't quite fix the low mid end.

I have been looking at an RCF MR10N301, a 10" sealed back very high efficiency midrange, with a phase plug, going into a DDS DMB-10N horn. This looks like a combination that ought to work for 250-1.5K or so. This should make a serious run at that low midrange upper mid-bass area I've been after. I will have to figure out a good combo for the top with that, but the HR90 should do this without much trouble (whole thing is getting big again...).

Thoughts? Anyone use one of those DDS horns for this type of thing? The RCF unit is quite sensitive, and coupled to the horn should provide more than enough sensitivity with respect to the bass unit.

Thanks!

Mike

I've been thinking about a mid-bass horn for quite some time. I plan to build a system some day with this type of setup, but I think the low bass section needs to be smaller, or differently shaped than the Khorn. Like you, I think the packaging becomes an issue when adding a mid-bass horn to the Khorn.

Just a thought. Have you considered making changes to the Khorn bass bin to improve the mid-bass? Specifically, enclosing the backs? I did this on the "FL" Khorn restoration www.voltiaudio.com/flkhorn.shtml and it really did improve the tonal characteristics of all the bass, especially the mid-bass. I wish I had done this to my own Khorns when I restored them.

Another thing that I've done recently to improve the mid-bass performance on my Khorns is to adjust the filter settings on the crossover point between the mid and woofer using a Behringer DCX2496 and separate amplifiers. I found I was able to adjust the crossover points and slopes to voice the Khorn bass bin to have a greater proportion of low bass to mid-bass, which I thought really helped a lot. This was especially true with using a 2" throat midrange horn/driver, where I was able to lower the crossover point to 300Hz on the midrange.

Greg

[djk]

I like the basic idea.

I also like the EV HR90, they sound great. What driver are you using? Both the EV DH1 and the Altec 288 sound great.

The mid and HF section of the JBL 3731 cinema system might be of interest. The dual horn-loaded 8s are about $700, the 3" compression driver and HF horn about $400.

The HF pattern is 90°H x 20°up, 30°down. A passive crossover design is available, so you could just bi-amp with some delay. Or you could tri-amp with delay.

[Guest " "]

take a look at the Patrician IV

http://archives.telex.com/archives/EV/Speakers/DIY%20Manuals/Patrician%20IV%20Part%201.pdf

A khorn wih a 4 way design.

You can make the top hat area a midbass horn, and go 4 way by using a smaller mid horn such as the k-700.

[Horatio]

I use a DH1012, which has a 1.4" throat. The DH1a's are 2" as I recall. I can vouch for your experiences on the HR90's, and as good as those sound, the 9040's are that much better.

Thanks for the info on the JBL setup: I'll have to get the dimensions on this beast. Like most others who've been questing for this grail, the package size is the issue.

-M

[Horatio]

Thanks for the reply- went to the site to see what it was you were speaking of- right- a 'Jube-like set of fletchings on the sides of the K. I looked at my Speakerlab-built bass boxes, and they have the basic template (top plate and bottom floor plate) that scope out these extensions, as one would need to do them. Would need to look at that vertical piece, as shown in the link. Pretty cool idea. I need to refinish these anyway, and this is probably something I will include when this is done.

On the mid ideas and your '2496 DSP: Yeah, I played around a little bit with a biamp setup using a Rane 23, where I could diddle the frequencies, but not the roll-off, and I liked being able to bring that turnover point down when the HR9040's were sitting on top.

This is probably a question best addressed off-line, but, I'd really like to know the details of how you're using that '2496. For what I have in mind, the usual flexibilities are needed (variable frequency, variable roll-off, adjustable gain for each section), but I would potentially need CD compensation if I eventually chose to keep the HR horns on top, and I'd need time delays. Moreover, I'd really like some flexible parametric controls on at least the bottom end, so that I can fiddle about tuning/compensating for the Khorn's response as it approaches the mid section. Can this thing do all of that?

Finally, what I am enjoying about all of this, is the challenge of the struggle to get that mid section right. PWK evidently struggled with this, and the 'Jube was I suppose, the final statement on that. But, there are the constraints we work with; as a manufacturer, one typically wants a product that can be cost-effectively produced, and which meets certain size envelope and price targets, for a given performance, let's say. As a hobbyist, we are a bit more free, as we can play with the price a bit more (e.g., appeal to more and different compression drivers, for example, and the use of digital crossovers and separate amps, etc.) and maybe, depending on the domestic situation, the size envelope.

The thought that keeps running around in my head, is, suppose we bandwidth limit the bass sections, and then stack these both away into one corner (OK, I have place I can do this with). We keep the upper end low enough that it is below the limits of humans to use for sound localization purposes. Then, we build 'satellites' that are fully horn loaded, and take up the rest. The midbass would be a challenge to get right. They are going to be big, too, I would guess, but smaller than if we had to pull the bass unit into the same package.

Thanks!

Mike

[seti]

I like the basic idea.

I also like the EV HR90, they sound great. What driver are you using? Both the EV DH1 and the Altec 288 sound great.

The mid and HF section of the JBL 3731 cinema system might be of interest. The dual horn-loaded 8s are about $700, the 3" compression driver and HF horn about $400.

The HF pattern is 90°H x 20°up, 30°down. A passive crossover design is available, so you could just bi-amp with some delay. Or you could tri-amp with delay.

Nice horns. I'll have to look up the specs on that HF.

[jwc]

The dual horn-loaded 8s are about $700

I was trying to figure out how to purchase that dual 8" loaded horn from JBL. Any suggestions on a dealer that would sell just that part of the system?

jc

[John Warren]

If it has a PN, they can get it

http://www.prosoundservice.com/JBLProfessional.html

[garyeanderson]

If it has a PN, they can get it

http://www.prosoundservice.com/JBLProfessional.html

Here is a parts break down of the JBL 3732-M/HF, I found it with google and JBL 3732-M/HF

Not sure it will help.

http://www.jblproservice.com/pdf/Theatre%20Series/3732-MHF.pdf

[djk]

JBL will get bent out of shape if you try and order the raw parts off that list.

Here is how I came up with the cost basis I listed (these guys are in Salt Lake City):

http://www.performanceaudio.com/cgi/product_view.cgi?products_id=18721

http://www.performanceaudio.com/cgi/product_view.cgi?products_id=18723