help choosing a 7" mid

[owdi]

Guys I'm not complaining about lack of midbass output but a tonality issue.

Thanks
Leo

They are the same issue, you need a BSC circuit. Try using TheEdge to model the baffle, and to model a BSC circuit. It's very easy to use.

Dan

 

[300Z]

Output and accuracy are the same issue?

I'll look into the edge.

Thanks
Leo

 

[AJinFLA]

I would suggest you use the RS28A's that you have and build a pair of these http://206.13.113.199/ncdiyaudio/mark/RS225_RS28A_updates/dayton_reference_rs225.htm
then use a fraction of the $2000 you saved by not buying the state of the art JBL's and buy some measurement equipment and software for your future projects LOL. Or the effect on the FR from placing the speaker on a desk rather than freestanding. Keep that active EQ handy.
Or go fully active (DSP) and use some state of the art drivers if you have that much $$$ to throw around (didn't realize that before, since you gave no such indication of the budget being that large). Then you can build any d**n speaker you want, fully adaptive to its enviroment. Gotta run.

cheers,

AJ

 

[300Z]

Well, the plan is to build a new set of speakers, buy the new amp + DEQ2496.
Factoring the cost for that it wouldn't be much more expensive to just get a nice set of active monitors... ?

And if space constraints wasn't the issue I wouldn't even bother building a box... I would just build an open baffle setup all active but living in an apt at this time I just got no room for that...

 

[Michael Chua]

Long Post

Hi 300Z

I have worked with the PL18 for many years. These are some of my experiences which you may find useful.

My listening environment was:

Room size: Approx 10-12 ft
Listening Distance: about 4 ft
Speaker rear to wall: about 1~1 1/2 ft
Use for near field monitoring.

My PL18 was loaded in a box of:
Box Vol: about 15~18L (Front Ported)
Tuned to about 42Hz.
Material 3/4" MDF.
Type: 2-way
Crossover: 1st order (no BSC)

HF: Vifa PL27TG35-06
At that time, this 1"Silk Dome Tweeter was the best in the Vifa range.

Other Vifa HF tested then with the PL18 were:

1) PL27TG05-06 (1"Silk Dome)
2) D25AG-35-06 (1"Aluminum Dome)
3) D25AG-05-06 (1"Aluminum Dome)

None of them gave me the tonality I was after. Only the PL27TG35-06 but I had to cross it low. Otherwise, I lose the vocal presence.

What I got from my speakers:
Clear vocals with enough presence. Able to hear the singers' breath between notes. The attack of the Acoustic Guitar strings and Brassiness in Sax (Kenny G type).

Obviously in larger rooms, the bass drops off quite drastically, so crossover have to be re-tuned. I should mention that it also doesn't measure flat with my LMS. I guess my ears are not flat or my hearing is faulty. Tonal referencing is done with Grado Headphones.

Weak in violins and mid-bass attack. May be too "Bright" for some listeners. May or may not suit you. Hope it helps.

Regards
Mike

 

[RJ]

Weak in violins and mid-bass attack. May be too "Bright" for some listeners.

I wonder what T/S parameter will identify that driver as being weak in the midbass????

Really, not trying to be facetious, I'd like in on the secret of determining how a driver will sound by looking at the T/S numbers.

After going through more than a dozen midbass units and trying to find one that sounds just right is quite expensive, not to mention finding the right box enclosure i.e. Sealed, Ported, TL etc.

I'm sure other readers would like to know also.

 

[Michael Chua]

Hi RJ

I am afraid I am not much help there. I am first to admit I cannot tell how a component sounds like by simply looking at the T/S. Perhaps others can, but I don't have that ability.

It is a costly approach, to have different test boxes made but that is the only workable solution for me to evaluate the sound of a driver.

The test boxes don't have to look good, just strong with front and back baffles detachable. I would have a few of them because not all share the same cutout. Likewise for the back baffle where the tuning port is. It's faster to change a baffle with a port attached to it. This is just for a 2-way. Repeat the entire process for 3-way and others.

From a business standpoint, it's part of development budget. When compared to a production run, even a pilot run of 100 pairs of bookshelf, the cost is minimal. When you factor in the full business cost (rent, labor, staff etc), R&D it can get pretty scary especially for a start-up.

Regards
Mike

 

[300Z]

Thanks for the input Mike, I have also used the Vifa D25AG-35-06, D27TG-35-06, and D27TG-05-06 tweeters with different x-over cut-off points and slopes and I just settled with the Dayton RS28A which is a much better tweeter IMO... now the Vifa tweeters just sit on the closet...

The PL18 isn't a bad driver, but it just isn't all that good either... To me i think it's time to move on...

I wonder what T/S parameter will identify that driver as being weak in the midbass????

I wouldn't call the PL18 weak in the output dept...

After going through more than a dozen midbass units and trying to find one that sounds just right is quite expensive, not to mention finding the right box enclosure i.e. Sealed, Ported, TL etc.

That's exactly my problem, if I had saved the $ spent buying drivers, x-over parts and enclosure material I'm sure I could just have bought a good active monitor and saved myself from the hassle.
I'm sorry, I do love to listen to music but I do not enjoy building enclosures and all... Hence the reason why i want to do it right this time around and just be done once and for all.

Guess I'll just take AJ's advice and build Mark's project... Or any1 got anything else to add?

Thanks
Leo

 

[Michael Chua]

Hi Leo

I think you have gone full circle with the Vifas. You are quite happy with the Dayton HF. My guess is that you are looking for something much livelier, something that the PL18 is not.

I will go with AJ on this. The RS225 would probably complement the RS28A better than the PL18.

All the best with your project.

Regards
Mike