Erse inductors in europe ?

[ucla88]

Originally Posted by xjr100

Sure, nothing if system in whole plays nice to our ears.

Just my notes: DXT is waveguided and designed as "directed" driver. That was the goal of DXT technology, offered by Seas. With notching it (especially on 6Khz - that notching does not look good to me on THIS design) you get hole in response of tweeter, which filled with response of woofer to achive flat responce. So, directivety of DXT is suffered a bit on certain freq and filled with wider directivity of woofer's response - that is why this design have better plots on of-axis measurements. It could be bad or it could be good - only listening test can confirm it. But ER18RNX's response @6kHz is not the best. That is the only what (possibly) bad could be.

Question to Mark: do you have driver's measurements in-cabinet to play with it? If so, would it be possible to get it in some importable format (Freq | Mag | Db), if possible.

Note to System7: do not play much with Visaton's boxsim - it is "thing on it's own" and far from the truth if you measure speakers with microphone. It is good just to play with Visaton's constructions, see crossover response, but nothing else.

P.S: All the speakers are compromise in terms of design and SQ

The notch at 6k doesn't cause a dip in the tweeter FR. It just, flattens a hump. See the aqua curve below. The aqua curve is the tweeter response after the network. No dip at 6k. The woofer isn't filling anything in. The woofer is twenty dB down here, which is as it should be when targeting 2nd order slopes.



As to releasing the curves-I have mixed feelings about that. I'll have to think on that one.

[voxxonline]

I do read this discussion, and start to understand what is what in crossover.
THX.

[voxxonline]

Gents, which amplifier would go with these speakers ? (s/h )
I crave for cyrus amplifiers, but you might offer some alternative to power speakers ?

[voxxonline]

I have a problem.

Europe audio is out of stock of 2.5 mh inductor , 0.41 ohm at 1.6 mm.

I have been trying to find alternative, but the value of 2.5 mh is for some reason not that popular.
What should I do ?
Alternatives on europe audio:
LJantzen 2.500 mH 0.590 OHm Cross CoilGBP 21.76


Jantzen 2,500mH 0,610Ohm Wax Copper Foil CoilGBP 25.59


JANTZEN-133Jantzen Wire air coil 2,500mH 0,368Ohm 1,80mm GBP 29.42

I am not that skilled to make a decision...
Thank you for help..

[system7]

The precise DC resistance of a bafflestep/bass slope inductor is not terribly important. Nor are the rest of them, for that matter. The design seems to specify an air-core coil, so anything between 0.2 and 0.6 ohm is fine. See it's added to the DC resistance of the (6 ohm?) driver, and as a percentage, it is about 5% level loss at the worst case of 0.6 ohm. If you can hear that, I'd be surprised. But you'd compensate by increasing the series tweeter resistor if fussy.

There is a school of thought that ferrite cored coils are to be avoided with AlNiCo magnets or Neodymium, but less critical with ferrite magnet loudspeakers.

[voxxonline]

I cut mdf slightly longer. Which adds about 3 litres to volume. I can cut it to dimensions, but it looks good now.
will 3 extra litres worsen sq or not ?

[voxxonline]

Baffle is precise, only side walls.

[ridikas]

I've stumbled upon this thread by accident. WOW System7, you really shouldn't be giving advice on loudspeaker design. I hope this sort of misinformation doesn't scare off potential builders.

Mark's design is 100% right on and the ER18DXT is possibly one of the best 2-way monitor around.

Low distortion (thanks to two very capable Seas drivers) and fantastic off-axis and power response.

2nd order acoustic slopes, as in the ER18DXT, will only have 180 degrees of phase wrap. 4th order designs have 360 degrees, the group delay is significantly worse.

Another design which attempts this task is Zaph's ZD5. It too uses 2nd order acoustical slopes. But whereas the ER18DXT was able to achieve perfect time alignment via the DXT's waveguide (which gives the proper tweeter off-set), Zaph's ZD5 uses an all-pass lattice network. Unfortunately, an all-pass network (in addition to the 2nd order acoustic slope) makes for a 360 degree phase wrap. The ZD5 will still retain an excellent power response.

The only commercial company (which I know of) doing 2nd order acoustic slopes is Dynaudio. They too however use an all-pass filter on the tweeter. I've never seen Thiel and Vandersteen measure well, or hit the claimed targets...

Mark's ER18DXT
Zaph Audio's ZD5
Dynaudio

These three are the "Holy Grail" of loudspeakers. Considering that Mark's design only has 180 degrees of phase wrap (lowest group delay, the other two are 360), should make it for an excellent sounding two-way monitor.

4th order acoustic slope crossovers are the easiest to make. The speakers literally design themselves with 2 components in the crossover. We listen to 4th order every day... From computer speakers, to movie theaters, to EVERYTHING sold at local electronic stores like Best Buy.

2nd order acoustic slope crossovers are incredibly complex, even if they don't look it on paper. Very few people have actually heard them. They can sound incredible.

[ridikas]

Originally Posted by voxxonline

I cut mdf slightly longer. Which adds about 3 litres to volume. I can cut it to dimensions, but it looks good now.
will 3 extra litres worsen sq or not ?

The extra 3 liters will give you better bass extension (and possibly lower q), if you tune the port/box stuffing right. I would leave it

[voxxonline]

Surprise surprise thread is alive.
I am slowly heading towards the end. Everything is ready, only put together and veneer left.
Hopefully few weeks later will report on result.
Ridikas, I still have not glued port (kept same as per bom) , can you advise me on tuning please, what to do - cut, buy longer or bigger diameter ?