Help with ideas for Altec mid-bass front horn using 416's

[atilsley]

I'm developing a two-way horn system, using 416 for bass and 902 for horn...probably 511 or 811 style.

I've looked at the large Onken bass cabinet...but I want to build a horn for the mid-bass that provides decent slam and attack to match the top horn.

I already have the GPA 416's, so I'm keen to try a horn for these drivers.

Opinions and help greatly apprecoated on what's available...and I'll be building the horns myself.

Some restrictions -

Cabinet size not to exceed 700mm deep...width OK...height OK.

I have small tapped horns to cater for the 30-80Hz range...so 70/80Hz target is sought...perhaps 90Hz at a pinch.

Upper cross-over around 800.

I've looked at a tractrix horn, with slotted (onken style) ports to aid bass depth. Cabinet size is quite good. On the b-d Design show room page, there's an example here. Another here.

Volvotreter has a very good small bass horn as well, see here.

I'm wondering how these style horns would compare with, say, the Altec 816? Should I consider the larger dual driver 817? (Cabinet depth 67cm, good.)

Are there any other designs worth looking at? For example, a modified 816 with dual ports for slightly lower bass extension (that is, same shape as 817, but with one driver?

Sorry for so many questions...but I'm really keen to get the right bass sound for my listening style.

Kind regards.

Andrew

[Earl K]

I'm developing a two-way horn system, using 416 for bass and 902 for horn...probably 511 or 811 style.

I've looked at the large Onken bass cabinet...but I want to build a horn for the mid-bass that provides decent slam and attack to match the top horn.

I already have the GPA 416's, so I'm keen to try a horn for these drivers.

Opinions and help greatly apprecoated on what's available...and I'll be building the horns myself.

Some restrictions -

Cabinet size not to exceed 700mm deep...width OK...height OK.

I have small tapped horns to cater for the 30-80Hz range...so 70/80Hz target is sought...perhaps 90Hz at a pinch.

Upper cross-over around 800.

I've looked at a tractrix horn, with slotted (onken style) ports to aid bass depth. Cabinet size is quite good. On the b-d Design show room page, there's an example here. Another here.

Volvotreter has a very good small bass horn as well, see here.

I'm wondering how these style horns would compare with, say, the Altec 816? Should I consider the larger dual driver 817? (Cabinet depth 67cm, good.)

Are there any other designs worth looking at? For example, a modified 816 with dual ports for slightly lower bass extension (that is, same shape as 817, but with one driver?

Sorry for so many questions...but I'm really keen to get the right bass sound for my listening style.

Kind regards.

Andrew

Pick your poison ;

[alancohen]

Sorry for so many questions...but I'm really keen to get the right bass sound for my listening style.

How your room is set up, the location of your speakers and the acoustic treatments you employ in the space will affect the bass response far more than small differences in enclosure configuration.

[GM]

As Earl's references imply, 700 mm is too short, so must be folded, making a high SQ 800 Hz XO very 'iffy' with a 416 or any other mid-bass horn driver.

GM

[bowtie427ss]

Hoffman's Iron Law is visited once again.

[atilsley]

Thanks guys

How about this from David Haigner?

Mouth is 840 x 650mm.

My drawings is the CAD 3D image....

[alancohen]

Hoffman's Iron Law is visited once again.

My education continues. I never heard of Hoffmam's Iron Law before:

Sensitivity and Hoffman?s Iron Law, or ?why you can?t have your cake and eat it too?

Given my current commitment to OTL amps, I am relegated to relatively low power. So I need high sensitivity and a sizable cabinet. Hoffmans Iron Law does not address the usual deterrent to this...the girlfriend/spouse. Get rid of her and the problem resolves itself.

[GM]

Thanks guys

How about this from David Haigner?

Mouth is 840 x 650mm.

My drawings is the CAD 3D image....

You're welcome, but no clue without design details, but again, your 70 cm depth precludes a 70-90 Hz XO point at any HF horn matching efficiency/transient response unless you increase the number of low Qt mid-bass horn drivers to further truncate it.

GM

[atilsley]

You're welcome, but no clue without design details, but again, your 70 cm depth precludes a 70-90 Hz XO point at any HF horn matching efficiency/transient response unless you increase the number of low Qt mid-bass horn drivers to further truncate it.

GM

Thanks GM

Yes, I realise now the xover will be closer to 100Hz, not 70. I'm OK with that, as the objective for this assignment is bass attack, without a massive cabinet. If that means 100Hz xover, so be it. I can't imagine Haigner promoting an expensive product in Europe if the bass wasn't fairly good. Remember, I still have dual tapped horns running nicely up to 100Hz. These are punchy and fast.

Last night I started on a to-scale mock up.

[GM]

You're welcome!

Even if Haigner's has rear vents I can't imagine it having what I consider proper bass response for good bass attack. Vents tuned high enough will have an 'impossible' phase response through the XO BW and tuned low enough will lean out the mid-bass too much for the TH's to fill. Like bowtie noted, the physics of the situation is against it.

Then again, the pair of DSL DTS20s I auditioned in Gainesville, Ga. didn't strike me as either punchy or fast, just 'accurate', like a good TL or very low tuned EBS, so have to wonder if we're having a failure to communicate. The Synergy horns OTOH had plenty of punch, speed, but then look at how deep they are, then you would have to add the depth of the compression chamber.

GM