Bassbabe

    First of all, sorry for the english language...

    I am in the proces of design a new subwoofer called "BassBabe" It is a sixth order vented bandpass using a neodymium 15" woofer. It will have a total weight of around 25kg (including speaker) It will play from 52-120Hz -3db and have an efficiency of 97.5dB halfspace. Theoretical max SPL should be around 127dB. Total volume (including wood) will be around 160 litres. You can see a sketch over here:

    http://img82.echo.cx/img82/9544/forum11jb.jpg

    The Bassbabe is intended for the small shows when you don't want to bring the big and heavey basscabs and don't want to use kilowatts of amping. Of course two prototypes will be build very soon.

    Best regards,

    Walt

    Zitat von "Walt"

    It will have a total weight of around 25kg (including speaker)


    i don´t see what´s so special about the design - besides the "flared" port and the weight maybe...

    Zitat von "Walt"

    It will play from 52-120Hz


    this is what a reflex-cab would do as well, being more "musical", too.
    anyway, looks like a downsized version of the x1...

    Hello,

    I saw some interesting things when simulating a cabinet for the 15ND-930 driver. It is true that the 1W response of a BR of 130 litres will have about the same response as the Bassbabe. But when you turn up the power (up to the 800W program power handling) effects due to BL non-lineairity come into play. The front port reduces cone movement for the bandpass. Therefore the cone can stay longer in its lineair range of motion. The simulations show that the bandpass can have 2-3db more output in the 60-90Hz region than a BR of same size and freq. range, both with the same 15-ND930 driver.

    The effect of port non-lineairity is also obvious. Both designs suffer badly from this effect. This costs you about 2-3dB on maximal output. Still I used a 40cm diameter vent for the BR simulation... Not very small for a 15" driver this class.

    Both sixth order bandpass and BR seem simple designs that is true but with all the additional non-lineair behaviour of driver and ports I think the Bassbabe will still be an interesting project to do. If it is possible I want to do a A/B/C with a BR-cab and a short rear loaded horn.

    Best regards,

    Walt

    I think, it´s not possible to build a 6th order with 25kg.
    I got an BR with the same driver, same weight, but very small size.
    You may have forgotten something or used too thin birchply.

    The price for the higher output will be much more step response time.
    If you reduce cone excursion, have you calculated the power compression, too?

    For what music should that sub be used?

    Where do you come from?

    »Wenn China erwacht, wird es die Welt erschüttern.« Napoleon Bonaparte (1769-1821)

    Hello Cyber,

    I am from the Netherlands. I used 700kg/m3 for the 15mm birch. I have taken into account powercompression due to running out of x-max (non-lineair BL) and heating of the voicecoil and also non-lineair behaviour of both ports.

    I have planned this sub for the small drive-in shows for recorded music. I know because of the six order bandpass principle this won't be a very musical sub but hopefully it will put out some serious SPL for its size and weight. A small sub for the non critical (small) gigs where you still want to have some good bass power.

    Best regards,

    Walt

    You´ve forgotten all the hardware and paint. That are quite a few kilogramms.

    Is the driver getting out of x-max in the bandpass?

    You got less voicecoil-movement, so the coil will be warmer than in the BR.

    »Wenn China erwacht, wird es die Welt erschüttern.« Napoleon Bonaparte (1769-1821)

    Moin Walt,

    i have build 2*15" BRs. With 10 kg total driver weight, the total box weight is 30 kg. Measures 80*60*65 cm. My trick was to use 13mm plywood and 24*48 mm massive Wood, we call "Dachlatte" to stiff out. The "Dachlatte" has nearly no weight...

    This works very good, so my conclusion is stiffing out is much more important than 18mm birchply, cheaper and lighter too. The benefit of 6th order BP is, you need no heavy speaker grille and less handles to move the lightweight box, sometimes the BR holes are enough.... Making the Box even more lightweight..


    (That`s part of my fun division :wink: i learned a lot about weight an cost. It`s very easy to build good sounding cheap speakers if truckspace and pro-finish is no problem)

    But i would never substitute even this orange monster with BP 6th order boxes. I know about the second Displacement minimum and its benefit, but they sound always ugly. :cry: Do you have to use a Spaceship ? Than it would be ok :lol:

    If you can read German, look here:
    http://www.paforum.de/phpBB/viewtopic.php?t=29459&highlight=leichter+autodach

    And have a look at Sound-Kliniks SK-Bastelhorn. In Simulation 100+ dB/1W from 50 to 200 Hz, in single use ! Ok it`s a pipe resonator @ 50 Hz (in single use) but there is no resonator above. And no port-turbulences.:
    http://www.paforum.de/phpBB/viewtopic.php?p=293745&highlight=#293745

    Gruß

    Lebe wohl, Michael Ebners Universum

    Einmal editiert, zuletzt von Hörnli (20. Mai 2005 um 19:39)

    Hello,

    So far no protoype is build so please notice that so far I have only run simulations on the BassBabe. Although simulations might be very accurate I still prefer hearing/feeling the real thing before making strong claims.

    The driver in the BassBabe driven at 800W RMS has a maximal cone movement of 13mm peak to peak. 18Sound quotes 7.5mm x-max but please notice this is just theoretically calculated using: (hvc-hag)/2 + 1/4hag

    In the simulation there is used an algoritm for describing the BL behaviour when the cone runs past (hvc-hag)/2 what should be more accurate than using the 7.5mm x-max value as quoted by 18Sound. If you use 7.5mm in the simulations that is more then 6.5mm so then there will be no x-max problems.

    As for the weight: yes, I didn't take into account all the hardware! But for such a light sub you probably don't need wheels and indeed you also don't need a steel grill.

    Best regards,

    Walt

    Moin Walt,

    i made late EDITs :oops:
    i`m shure you will build the best engineered BP ever, but the Resonators keep resonating....ok, i think you know it by yourself....compromises...please support me with Punishers if we meet at a livegig. :wink

    Gruß

    Lebe wohl, Michael Ebners Universum