Possible enclosures for a Monacor SPH 60X

[GM]

sorry GM,
my KORNETT gets 35 HZ, tight strong fast.

I was referring to these in post #15: "That`s why I asked for needle or half chang or fonken ..."

Regardless, the Kornett is a relatively complex (by novice builder standards) dual driver, dual horn with what appears to be a rolled off LF response as already noted, though not knowing the details of how the measurements were made we do not know if it sounds that way in a typical room, so by my standards it may not be all that 'strong'.

Anyway, if everson were not so unreasonably (IMO!) dead set against any passive filtering I would suggest using two 60X drivers in a 2x larger ML-TL or ML-horn and use an inductor to roll off one at the baffle step, yielding a simple build with enough SPL down low to easily do 35 Hz at low distortion in-room.

GM

 

[rjbond3rd]

I`d like not to make any circuits

Hi everson, making a BSC is a snap! It's just a coil and a resistor in parallel on the + speaker terminal. Substitute an 8-ohm L-Pad for the resistor and it's now an adjustable 'tone control." Proper coil + some resistance = proper bass.

Plus you've gained a new knob to twiddle. If you can accomplish the same thing in other ways (e.g. digitally, or by using a wide baffle), that's cool. But otherwise, what's not to love about this simple and powerful tweak for cabs that require it?

 

[everson]

OK, let me ask a more concrete question:

Could I use this exact cabinet, with these exact measures ( http://www.ejjordan.co.uk/diy/ - MLTL-48 )?

Any other plan with measures (or a link where I could calculate measures)?

 

[Scottmoose]

OK, here's one possible, based on Greg's suggestion for twin drivers per channel, rolling one off above the baffle-step frequency (415Hz).

45in x 9.5in x 6.0in (HxWxD). Central point between the two drivers (mount as close together as possible) 11in down from internal top. Vent 2in diameter 0.75in long, close to internal base as possible. ~max flat design, so damp to taste either by increasing the internal vent length or damping things down. Stuff 0.5lbs ft^3 of hollow fibre material from the top 28in down.

 

[Scottmoose]

Single driver version: 34in x 6in x 5in (HxWxD) Driver-centre 8in down from internal top. Vent 2in diameter x 4in long, again close as possible to internal bottom. Stuff 0.5lbs ft^3 from the top 20in down.

Step frequency at ~608Hz, so you'll either need them in corners, or a compensation circuit.

 

[GM]

Could you suggest a specific MLTL design? Any plans so a newbie could build it easily by following plans?

What's wrong with the one I already posted?: http://www.diyaudio.com/forums/showthread.php?postid=1517208#post1517208

GM

 

[GM]

Could I use this exact cabinet, with these exact measures ( http://www.ejjordan.co.uk/diy/ - MLTL-48 )?

Yes, though like any other non-horn or 'helper' driver alignment it too will require BSC if positioned out in the room.

GM

 

[everson]

Thank you, guys!

I`ll consider them. I`m gonna make my final decision soon.

What about this one: http://geocities.com/rbrines1/Pages/Proposals.html#RS 40-1354a

Again, thank you for your efforts!

 

[Scottmoose]

That's the folded version that Greg was talking about.

 

[GM]

Actually, it's the same one I referenced if you scroll down the page I linked to. For whatever reason BB has it posted in two different places.

GM

 

[everson]

What a coincidence.
Thank you, guys.
I`ll probably make one of those 2.

 

[giantstairs]

2x ML-TL

OK, here's one possible, based on Greg's suggestion for twin drivers per channel, rolling one off above the baffle-step frequency (415Hz).

45in x 9.5in x 6.0in (HxWxD). Central point between the two drivers (mount as close together as possible) 11in down from internal top. Vent 2in diameter 0.75in long, close to internal base as possible. ~max flat design, so damp to taste either by increasing the internal vent length or damping things down. Stuff 0.5lbs ft^3 of hollow fibre material from the top 28in down.

A few questions about this design as I have a pair of sph-60x sitting in their boxes.

First, could the rolled off driver be placed on the side of the cab, at the same height as the one in the front? Would this be at all beneficial?

Could the cabinets be made taller as I usually listen while standing up. This I find to be the main problem with my small bibs.

I remember reading somewhere that the monacor sph-68 has better highs -- any thoughts of using this one fullrange with the sph-60x rolled off?
http://www.monacor.de/typo3/index.php?id=84&L=0&artid=2154&spr=EN&typ=full

Lastly, how would these cabs sound compared to a bib with a single sph-60x? I am looking for a cab that will have good bass at low listening levels as I rarely get the chance to "rock out".

Thanks!

 

[GM]

Assuming it's just going to be used for BSC, side mounting the 'helper' driver is fine, though short of making it bipolar nothing beneficial comes to mind at the moment if it's the same size and/or model. For larger sizes though, it allows a potentially narrower baffle depending on the drivers used and shifting it down to get some extra boundary gain/reduce floor 'bounce'.

Up to a point, cabs can be stretched and the vent shifted upwards to maintain a good driver/vent distance for a given Fp, but there's a point where the CSA of the pipe is reduced enough to begin 'choking' the driver(s), so you'll have to choose the drivers to figure these variables out.

IMO dual drivers always trump a simple pipe horn as long as you have an amp with enough power to handle the load.

GM

 

[hm]

giantstairs

Hello,
right the 68 X is better in the highs.

A bipol is a better solutuion.

here the Kornett measurement:

 

[giantstairs]

2x mltl

OK, here's one possible, based on Greg's suggestion for twin drivers per channel, rolling one off above the baffle-step frequency (415Hz).

45in x 9.5in x 6.0in (HxWxD). Central point between the two drivers (mount as close together as possible) 11in down from internal top. Vent 2in diameter 0.75in long, close to internal base as possible. ~max flat design, so damp to taste either by increasing the internal vent length or damping things down. Stuff 0.5lbs ft^3 of hollow fibre material from the top 28in down.

a few more questions as i'm about to order some birch ply (not bb).

first, the vent length is .75in so just the cut out in the ply (assuming 1.9cm thickness)? could it be made by a rectangular cutout in the front baffle, a la demetri? 1.3in by the 9.5in width looks to be close. of course this will be difficult to adjust if need be and i may only be able to get 1.8cm thickness so not sure if this matters.

second, what would be an appropriate inductor to roll off the second driver? having no experience in passive parts i don't know where to start.

last, can these be pushed into corners or at least up against a wall, or do they need to be out into the room?

thanks for all your help,
larry

 

[giantstairs]

scott, gm, anyone?

 

[Scottmoose]

Re: 2x mltl

first, the vent length is .75in so just the cut out in the ply (assuming 1.9cm thickness)?

Yes, that's easiest.

could it be made by a rectangular cutout in the front baffle, a la demetri?

Yes. Just don't exceed a 1:9 HxW ratio.

second, what would be an appropriate inductor to roll off the second driver? having no experience in passive parts i don't know where to start.

Have a read up on crossover design. It will pay dividends: http://sound.westhost.com/lr-passive.htm

last, can these be pushed into corners or at least up against a wall, or do they need to be out into the room?

Should be OK. Damp them to taste once in-room.

In terms of placement, the purpose of the second driver is to give you enough bass so that you don't /have/ to push them against the walls/corners. If you push them up against walls/corners, it sort of defeats the whole idea (if I understand correctly).?

No, it's to compensate for baffle step loss. Room gain is a separate issue, although it can assist with the former. In practice, you can't have too much gain -just damp out what you don't need.

 

[perempe20]

Would this design work?

An externally hosted image should be here but it was not working when we last tested it.

I'm also considering the Alpha horn.

 

[giantstairs]

i just found this review of a speaker using a monacor 5inch driver, made right here in spain of all places:

http://www.6moons.com/audioreviews/passionsound/passion.html

it doesn't look like an mltl to me, probably more similar to the design in the above post, however, in the second page of the review there is what looks to be a tall, wide mltl though i don't see the vent.

the design apparently uses the monacor sph-64xad which i believe is the 4ohm version of the 68xad. i'm not sure why the 4ohm would be better than the 8ohm but it seems to make a difference according to the designer.

the review implied, as i understood it, that there is no filter used. i'm not sure how that enclosure with it's narrow baffle wouldn't need bsc.

also, the review talks about how light the enclosure is so i would imagine it is made from poplar ply (which i've found horrible to work with because of its softness).

in any case, it seems a full, satisfying and simple design is possible with the monacor 5 inchers. having said that i'm still drawn to the double driver variation and will likely go that route.

 

[GM]

i'm not sure why the 4ohm would be better than the 8ohm but it seems to make a difference according to the designer.

4 Ohms draws more current for a given SPL, ergo Qes, Qts rises quicker, lowering the mass corner, so combined with proper pipe loading no BSC is required if the average SPL is high enough to keep the VC heated up enough. I know of at least one driver manufacturer that did this to good effect.

This assumes of course that the amp can handle the extra current required for 'fast' transients, which is often not the case even if it either has the taps or rated for it in marketing docs if no wattage rating is included (or at least that use to be the case).

GM