Supravox 400-2000 - what to do with them?

[vinylnvalves]

Chris

With regard to the mic roll off, I should have said that the jbl2482 is cut off at 1.8 kHz, I didn't have the HF channel turned on. I think all the phase change is floor bounce, how do design a speaker without having the driver low down to avoid it. I cannot face taking these monster cabinets outside!!!

[chris661]

Try putting some cushions/blankets on the floor mid-way between mic and speaker - that'll absorb some of the floor reflections.

The bit about mic rolloff was about the bottom end. Behringer ECM8000 is a few dB down at 20Hz, and also a little at 30Hz. Something like that might be why you're not measuring much below 50Hz.

Chris

[vinylnvalves]

Had "golden ears Dave" around at the weekend to listen to the new bass arrangement. We listened to sealed, BR and leaky configurations, we concluded that the BR was the best having more "snap" as Dave would put it. Got the port tuned quite low 25 hz EBS?, with some help from the DSP to lift the bottom end. Have a stone wall filter @ 25 hz to manage cone flap if it should occur That almost gives me the green light to build some proper cabinets for Owston. I just have one nagging question- would a MLTL be better than the ESB BR, and if worth a punt, how do I fit it in my small 200 Ltr cabinets. A cry for Scott's help goes out I think. I had been kicking some parameters around in MJK's spreadsheets using some data which GM had posted for Altec 416's as a starting point without much success.

[chris661]

ML-TL cabinets tend to be fairly tall and slim, acting like a quarter-wave resonator, but then squeezing the LF through a narrow opening, which drops the tuning a bit.
Ported boxes delay by half a cycle at the tuning frequency, by using the slug of air in the port as a mass, and the air in the cabinet as the spring.

To model an ML-TL, you can use Hornresp. Set for an offset driver layout, S1=S2=S3=~Sd, and then S4=S5=port area, and L12 is distance from the top to the driver, S23 is distance from driver to port, L34 should be short as possible, and L45 is port length.

Not sure if you'll be able to put an ML-TL setup inside your existing cabinet, but might be worth a go.

Chris

[IslandPink]

Example Hornresp set-up :

[vinylnvalves]

Thanks guys. I have used horn resp in the past. I think Martin kings math cad spreadsheets offer a better insight. It's not the using of the tool that's the issue, it the lack of experience which GM and Scott have knowing what to adjust to get the flattest response. For instance moving the port up from the end of the line 5 inches or so has a big effect on the smoothness of the response without stuffing, reasons I don't understand, I assume it breaking a harmonic or something similar.

[vinylnvalves]

Just before i go and generate saw dust.

I wanted the collective opinion on this MLTL and whether it will work that well and/or have any benefit over a EBS BR in the 200 ltr cabinet. I have realised that if i integrate the TPL's in to the bass cabinet i get around 250mm of height and around 40 litres more.

I have ran a simulation, see attached and it looks not too bad, before i stuff it.