Is that really +/- .5dB 40-20K?? No EQ? Wow!
John
Is that really +/- .5dB 40-20K?? No EQ? Wow!
John
I did a little recheck of the scale on the new toy. The dsp8024 has a 1db and a .5db setting. It looks like when in the .5 db setting there is a 5db difference in the grid squares, and for the 1db there is a 10 db spread. So it is more like +/- 5db.
I'm ignoring whatever's going on down there at 180 Hz.
It has nothing to do with the crossover (assuming you've got the two 100-Ohm resistors in there,) and a different measurement technique is required to read what a woofer's doing below 250 Hz.
8024 manual nowhere says what the scale is on the RTA display that I can find. Resolution can be set to either 0.5 or 1.0 dB per pixel. I count 8 pixels per dotted line using a magnifier. Thus, the scale is either 4 or 8 dB, depending on the resolution setting.
So, +/- 3 dB, then, and the HF compensation is certainly "happening."
- Yes, you've got it correct .Originally Posted by Zilch
John,
- Those are really cute speakers . Maybe I'm the one who should be buying some le120h woofs for a similar project .
- It's nice you got some measurement stuff . I also use the 8024 as a portable RTA . It's quite utilitarian in that regard .
- Personally, if it was my project / I'd like to see a couple more db of response between 1.6K & 3.2K . But, that's a preference thing. This would unfortunately require a rework of at least one portion of the circuit .
- Since this is an area of great personal preference , that curve could easily be working for you, so I'll shutup now.( Fletcher Munson curves , etc., etc. )
- That perfect Vee "hole" at 160 hz is likely just a "hard surface bounce" reflecting ( at 180° ) into the mic. This will contaminate the FR measurement in that area .
These DIY 4425 are very nice!!
This might be a bit off topic but I hope someone has the answer on this one. I'm building cabinets for my DIY 4430's and I'm wondering if the horns must be directly placed underneath the bass-speaker (I hope not from a cosmetical point of view).
All 4425's seem to have a certain angle between the bas-speakers and horns (2214 placed in the middle of the cabinet an the horns on the sides). Is there a reason??
I have a follow-on question. Are the 4425 horns ever rotated 90 degrees and the speakers placed on their side?
We've seen an occasional pair of 4430's used sideways with the horns rotated.
Both 4430 and 4425 are symmetrical dispersion horns. Lay them on their side and the distribution should be the same. There are differences in detail, but I would just do it and not rotate the horns....
If the drivers are not in vertical alignment, the plane of time alignment is not horizontal. Some think that matters, though I could conceive an argument that it might be better in certain situations.
Time alignment's a third- or fourth-order consideration to me. For some, it's prime....
What's 1st and 2nd? Group delay? Flat response? Dinner and a show?
First order is frequency response. Do these drivers play well together? Is there a compatible crossover region? Is the box sized and tuned for optimum woofer performance?
Second order: How do it sound? Have I selected the best crossover frequency and slope for this combination? Is my HF compensation right? Do these drivers just plain suck in this configuration no matter what I do?
Third order: Sound field. Is this the dispersion and imaging I was aiming for? Are there reflections and/or resonances I gotta attend to? How do I fix this stuff?
Fourth order: Time alignment and aesthetics. I don't give much of a whit about either, but I TRY to pay some gratuitous attention to them....
There is a paper on this horn and monitor (around somewhere)
Its explains why and how they did what they did at the time.
The LSR paper is also a good read and explains how JBL's evolution of monitor design has moved on in so far as studio applications go. Far more importance is given to controlling early reflections and the off axis power response as opposed to flat on axis response. In these soa designs flat on axis reponse is a given, but only by virtue of complex system design innovations like proprietry drivers & waveguides, elaborate crossover networks.
The 4425 and 4430-35 are what they are so there's not much point messing with them too much.
Ian
John W
Behringer make a lot of affordable products in the catalogue range, hare in the United Kingdom they are selling them at crazy prices! The site is called “Trunkey”
http://www.turnkey.co.uk/web/homeAction.do?dispatch=homePage
I’m keeping my eye on there products, and will soon upgrade my EQ’s to 1/3 octave for my home cinema, but the model you have there, how much did that sweet baby set you back?
I have a Behringer 8024 which is an older model ultracurve pro unit. I bought mine used for about $120 then also needed to get a Behringer mic and some cables, so altogether about $200.
Normally I only pull it out to use the RTA functions, which it handles very well. The equalizer seems to add a little noise and fuzz so I don't leave it connected to the signal path.
The newer Behringer DEQ2496 is supposed to be a nice step up.
John W
The more I read the reviews from the that are around, the more and more it convinces me to purchase around x5 EQ for the home cinema, matching of course, as my current EQ set-up is very tricky too get it all aligned and calibrated.
Once that is done, I may look forwards to a brand new (RTA) from the same manufacture, but this is a whole long way off, but it will happen…
Thanks for the comment; I’m sure it will come in very handy.
PS. As for noise, could be the input cables, does the model have (XLR) inputs?
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