New "Kinoshita" type build

[phase_accurate]

Here you can have a short glimpse of the innards of an original Kinoshita refurbished by Kenrick Sound:

YouTube

Regards

Charles

 

[jazbo8]

So basically nothing according to the video! Just extra thick cabinet walls and a support for the TAD horn.

 

[Brendanaudio1]

Can't seem to locate the thread, not that I can read French anyway, could you please share the build plans here?

Here is a link:
Kinoshita RM7 de Nicolas C.

So basically nothing according to the video! Just extra thick cabinet walls and a support for the TAD horn.

Hi Jazbo

From what I have seen, just some bracing strips in the corners, and halfway on the side and back walls. Thats what I did on mine.

 

[jazbo8]

Thanks, that's helpful.

 

[Brendanaudio1]

Nice project. <Snip>

Hi Hollowboy. I have looked at the router guide but don't think I will do it that way. I am thinking of doing all 4 quadrants at once. So I have had a guide bar cnc cut (Tactrix curve). I will make a Disc on a horizontal laithe using this guide as a profile. Thats what I'm going to try anyway. Saw it done like that on one of the Thai sites.

When I first played, all I did was set a HP and LP of 900Hz. Was not good. I was not sure how to measure time alignment of the drivers, so ended up spending days, if not wekks doing this by ear. The crossovers are now running 12dB slopes crossing at 900hz, no EQ and a time delay of 2,35ms

They are sounding very good now. The deepest, most natural base ever. I am deiving the Beyma's, bridged, so a 4 ohm load, with Bel Canto Ref1000 mono's, The Horns, and tops are being driven by Firstwatt F5.

I would like to post my current measurements that I tried to take with REW using a Umik-1, and for one of you experts to have a look, and maybe help me with some further adjustments/advice.

Thanks for all the posts so far

 

[Brendanaudio1]

Just 2 pictures of the completed speakers to put them in perspective

The first pic is complete with the Ports and all.

 

[phase_accurate]

Hi Brendan

What happens if you reduce the delay in your crossover by 1.1ms or even 2.2ms ?

Regards

Charles

 

[Brendanaudio1]

Hi Charles

The less the delay, the more "Smearing" I get on the s's and t's. I will set up and take REW measurements tomorrow, as I have it, and with no delay, then you can check and advise me better. Thanks so much

Regards
Brendan

 

[Brendanaudio1]

Just need some advice on the measurements. 1- mix placed at the listening position with sweep over both left and right channel? Or 2- mix placed 1m in front of a speaker with sweep done on that speaker only. 3- individual sweeps of the bass drivers. And then kids/tops with mix placed in front of the speaker?

Please someone advise!! Thanks

 

[LineSource]

Say it fast 3 times ....

Baby Butt Cheeks,
Baby Butt Cheeks,
Baby Butt Cheeks,

Gotta Smile ...

==========
The AVS forum has a MTM build thread using AES TD18H woofers and the SEOS-24 waveguide with the 1.4" coaxial BMS 4594Nd compression driver. Three separate cabinets for the M + T + M components. The SEOS-24 (500 Hz) and SEOS-30 (300Hz) come with a 2" CD option. These larger SEOS waveguides might fit your future "Building BIG" designs.

SEOS-24, BMS 4594ND, Dual AE TD18H+ - AVS Forum | Home Theater Discussions And Reviews

 

[Brendanaudio1]

Thanks linesource. Will definitely look into it. Would the seos fit the jbl 2445?

 

[AllenB]

The less the delay, the more "Smearing" I get on the s's and t's. I will set up and take REW measurements tomorrow,

It sounds like this problem has more to do with your crossing over. Crossing is more than filters.. sometimes there will be a correct combination and sometimes there will not.

This isn't to say that linesource doesn't make a reasonable point too. Your horn seems like a good temporary placeholder.

 

[globalplayer]

The crossovers are now running 12dB slopes crossing at 900hz, no EQ and a time delay of 2,35ms

2.35ms will be roughly a 0.81m / 2.67ft distance.
Looks a bit too much to me.

 

[hollowboy]

Thanks linesource. Will definitely look into it. Would the seos fit the jbl 2445?

Linesource usually recommends good stuff

The Seos 22 looks like it can be made with a 2" throat.
SEOS-22 - Horns by Auto-Tech

Note that they are pretty short, and a Seos' throat will have a wide angle compared to the snout of a 2445. The discontinuity will act like a diffraction slot, which may or may not be what you want (lots of older JBL horns had sharp angles and diffraction slots).

The 2445 is the "old driver configuration" shown in the attached document:

http://www.jblpro.com/ProductAttachments/tn_v1n21.pdf

These older JBL drivers have very low exit angles. If you want to avoid a discontinuity in throat angle, you need to match them to horns with similarly long, slowly flaring throats.

The Inlow Sound website has a good example.

EDIT: in post 1, you refer to "a pair of JBL 2425 compression drivers" (5kg driver with 25mm exit), then later to 2445 (>10kg driver with 50mm exit). Do you have both, or is this just a typing error?

 

[phase_accurate]

I guess on the 2344 horn shown he is using the 2425 and he has the 2" ones for a new incarnation of his speaker.

Regards

Charles

 

[Brendanaudio1]

Hi Hollowboy. The statement by phase is correct

 

[Brendanaudio1]

Help Needed

Hi guys. I'm back. sorry for going quiet, but work kept me out for as while.

Some more info on the build. Internal dimensions are as follows:1148 h x 738 w x 520 d.
Please note that these are the internal measurements, giving me an internal volume of 440l. My ports are 85mm in diameter.

Would someone be able to help me by calculating the correct length that I should go using the Beyma sm115n which have an fs of 35hz. The ports are currently only 60mm in length, and there are 4 per speaker cabinet.

I am also needing assistance with the crossover. PPPLLLEEEEAAAAASSSSSEEEE
As mentioned previously, I am crossing over at 900Hz, both LP and HP are sloped at 24db/octave, I think. Some advice from the experts would be greatly appreciated.

 

[Brendanaudio1]

Right, and here is a Rew measurement that I attempted. If someone could check it out and maybe advise further.

 

[Brendanaudio1]

Right guys. After trying my best, I can only get the compression driver to sound average, to slightly above. Sounds thin to me. I sat auditioning a couple of my other drivers, namely a pair of lowther dx3 and tannoy 2528 10” dual concentric. The kids on them are unbelievable. I think that I must make a rear chamber to seal the centre driver off and use one of these pairs instead of the jbl compression. Any thoughts?

 

[hollowboy]

Right guys. After trying my best, I can only get the compression driver to sound average, to slightly above. Sounds thin to me.

What went wrong? Earlier, you said "They are sounding very good now."

Your posted FR graph shows the range below 500Hz as +10dB relative to the treble, so it shouldn't sound thin, unless you like a very bass-heavy presentation. Was that test done in the same place that you listen?

On the FR plot, the 1-2kHz range is a little low, maybe that's the problem?
I'd suggest taking measurements at a few different locations, including exactly where you normally sit, and do some eq based on that.

I sat auditioning a couple of my other drivers, namely a pair of lowther dx3 and tannoy 2528 10” dual concentric. The kids on them are unbelievable. I think that I must make a rear chamber to seal the centre driver off and use one of these pairs instead of the jbl compression. Any thoughts?

I've got a couple of 2425J drivers. I've only given them a quick listen, but they seem worthy - I plan to use them in a build. I'm surprised that you'd prefer a Lowther to them.

I'd like to see detailed FR plot of the JBL drivers vs a plot of the Lowthers.