Bass support below 150 Hz

[astrojet]

Hi all.

I just finished building a pair of ~150 Hz tractrix front horns with vintage dual-concentric drivers. I'm hoping you will offer advice on what I should do to fill in the bass down to about 40 Hz or so. I have a spare 30W X 30W gainclone amp that I'll run the woofers off of, so the system will be tri-amped.

My room is about 1500 ft^3 but has a large walkway (~ 8' x 7') that opens into another room of equivalent size. I listen to a huge variety of music at relatively low volumes, with a focus on bebop jazz and surf guitar. Floors are hardwood and two walls are about 1/2 covered with windows.

I'd like to keep the woofer project relatively small, but I can spare a little space, especially if I build stereo woofers and use them as stands for the horns. The lowpass seems too high to hope for omnidirectional bass. I have no pre-conceived devotion to ported or sealed or horns, etc., so please suggest whatever. I have enough of a woodshop to build most designs. I'm not really looking to design something myself, rather I hope to find a community trialled solution. Of course as cheap as possible would be great, but I can spend a modest amount on a good solution.

Thanks heaps for any thoughts!

 

[PeteMcK]

The woofer section of this:
http://www.diyaudio.com/forums/mult...-reference-3-way-audio-society-minnesota.html

Or, cheaper, this:
https://sites.google.com/site/undefinition/tarkus

 

[whgeiger]

Klipsch

Hi all.

I just finished building a pair of ~150 Hz tractrix front horns with vintage dual-concentric drivers. I'm hoping you will offer advice on what I should do to fill in the bass down to about 40 Hz or so. I have a spare 30W X 30W gainclone amp that I'll run the woofers off of, so the system will be tri-amped.

My room is about 1500 ft^3 but has a large walkway (~ 8' x 7') that opens into another room of equivalent size. I listen to a huge variety of music at relatively low volumes, with a focus on bebop jazz and surf guitar. Floors are hardwood and two walls are about 1/2 covered with windows.

I'd like to keep the woofer project relatively small, but I can spare a little space, especially if I build stereo woofers and use them as stands for the horns. The lowpass seems too high to hope for omnidirectional bass. I have no pre-conceived devotion to ported or sealed or horns, etc., so please suggest whatever. I have enough of a woodshop to build most designs. I'm not really looking to design something myself, rather I hope to find a community trialled solution. Of course as cheap as possible would be great, but I can spend a modest amount on a good solution.

Thanks heaps for any thoughts!

The only bass enclosures that are going to match what you already have (amplifiers included), is a pair of corner horns. The designs of Paul Klipsch are well known, and the only challenge here will be the woodworking. The driver cost will be reasonable as well.

Regards,

WHG

 

[Studio Au]

http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Serious Sub_copy.pdf

 

[astrojet]

Thanks for the great suggestions. I'd given corner horns some consideration, but I don't think my room is appropriate. I really only have one free corner to work with, as the others have adjacent windows. I've also thought about Volvotreter's tangband horn. Maybe this is still something to consider.

Sutdio Au: Holy crap. 2 X 21". I'm very certain this would sound good, but I'm not sure my listening levels (in this case 'feeling' levels) nor my audiophileness are up to it.

PeteMcK, the SB 12" looks pretty nice and the prices aren't terrible. Like you, I'm in the Austral-pacific. Do you know of any good mail orders around? I've shipped from Madisound in the past, but for a chunky set of woofers it might be a little extreme.

All in all, I listen at relatively low volumes and care equally about imaging and depth. I want low-end weight, but I don't want it to overpower everything else. With that said, those 21 inchers would probably work wonders on my MOOG / organ vinyl collection.

Thanks again for the suggestions. I'm still left wondering...

 

[whgeiger]

Overkill

http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Serious Sub_copy.pdf

Precision Device's PD2150 driver is a favorite on mine also; but putting it in a sealed enclosure and driving it with a 30 watt tube amplifier, is like a flea trying to mate with an elephant.

Regards,

WHG

 

[Inductor]

astrojet,
Humm, I think you have to start making decisions in relation to type of enclosure/sub.
Austral-pacific, humm, what city is that...
From Speakerbits (Australian company) you have 12" Peerless 830669 315 SWR 39 good for a sealed ~90/100L (Qtc = 0.8). This driver is 91.5 dB/2.83V/m (2Pi) and goes in the 30's Hz region, 30Hz@F9. One per side would make your day I guess... driver link
Ortofon, Thorens, Scan-Speak, Speaker repairs, Turntable repairs, Vinyl accessories

 

[whgeiger]

A Change in Tack

Thanks for the great suggestions. I'd given corner horns some consideration, but I don't think my room is appropriate. I really only have one free corner to work with, as the others have adjacent windows. I've also thought about Volvotreter's tangband horn. Maybe this is still something to consider.

Sutdio Au: Holy crap. 2 X 21". I'm very certain this would sound good, but I'm not sure my listening levels (in this case 'feeling' levels) nor my audiophileness are up to it.

PeteMcK, the SB 12" looks pretty nice and the prices aren't terrible. Like you, I'm in the Austral-pacific. Do you know of any good mail orders around? I've shipped from Madisound in the past, but for a chunky set of woofers it might be a little extreme.

All in all, I listen at relatively low volumes and care equally about imaging and depth. I want low-end weight, but I don't want it to overpower everything else. With that said, those 21 inchers would probably work wonders on my MOOG / organ vinyl collection.

Thanks again for the suggestions. I'm still left wondering...

If no big corner horns, then big drivers with big amps are needed. Even though listening levels are "low", it stills takes a lot of power, and a lot of air movement, to make deep bass notes audible.

These drivers are big and near by.

P.Audio System Co., LTD

Regards,

WHG

 

[Cask05]

The only bass enclosures that are going to match what you already have (amplifiers included), is a pair of corner horns. The designs of Paul Klipsch are well known, and the only challenge here will be the woodworking. The driver cost will be reasonable as well.

Regards,

WHG

See https://community.klipsch.com/index.php?/topic/148054-quarter-pie-bass-horn-measured-fr-how2build-and-hornresp/

 

[tb46]

Hi,

How about something like Les Hudson's Dual 12" PPSL? (Or maybe 2x15"?) See also:

http://www.diyaudio.com/forums/subwoofers/177905-thread-those-interested-ppsl-enclosures.html

Regards,

 

[PeteMcK]

In Aus, here for SB:
Essential Audio - Loudspeaker Kits, Hi-Fi Loudspeakers, Guitar, Bass & PA Loudspeakers! Eminence, Celestion, Jensen, Scan Speak, Vifa, Peerless, SB Acoustics, Fountek
Here for P Audio:
http://www.cannonsound.com.au/shop/brands/brands-n-z/p-audio/

 

[astrojet]

Thanks again for the suggestions (and the links to the Aussie sites). I'm in NZ.

This truly is a great online community.

Some of the ideas are grand, perhaps too grand for my room (even if I did underestimate my room volume by ~30%..... 12' X 20' X 9' = 2160 m^3).

I'm sure the 1/4 pie box with a 4' radius would sound nice but after my wife was so pleasant in response to two large front horns, I don't want to push my luck.

As a first try, I'm leaning toward Inductor's idea of a couple of sealed 12". From PeteMcK's links, it looks like SB and Scanspeak as well as Peerless might be available. Pending additional suggestions, I'll decide on one of those for a sealed enclosure and hope for the best. I might ask additional questions about volume, series capacitance, etc. in the near future.

I'm really left uncertain whether the amp I'll use (dual mono at 30W) will struggle, but it might be possible to adjust the gain on my pre with a tube swap if it struggles.

Further thoughts are still appreciated, but I'll move on this relatively quickly.

All the best.

 

[Retsel]

Two other suggestions for high quality bass are:

Dipole, but would require much more amplification.

Karlson, and your 30 watts could be sufficient.

 

[zobsky]

Hi all.

I just finished building a pair of ~150 Hz tractrix front horns with vintage dual-concentric drivers. I'm hoping you will offer advice on what I should do to fill in the bass down to about 40 Hz or so. I have a spare 30W X 30W gainclone amp that I'll run the woofers off of, so the system will be tri-amped.

My room is about 1500 ft^3 but has a large walkway (~ 8' x 7') that opens into another room of equivalent size. I listen to a huge variety of music at relatively low volumes, with a focus on bebop jazz and surf guitar. Floors are hardwood and two walls are about 1/2 covered with windows.

I'd like to keep the woofer project relatively small, but I can spare a little space, especially if I build stereo woofers and use them as stands for the horns. The lowpass seems too high to hope for omnidirectional bass. I have no pre-conceived devotion to ported or sealed or horns, etc., so please suggest whatever. I have enough of a woodshop to build most designs. I'm not really looking to design something myself, rather I hope to find a community trialled solution. Of course as cheap as possible would be great, but I can spend a modest amount on a good solution.

Thanks heaps for any thoughts!

1. 150 Hz tractrix horns won't normally go down to 150 Hz. More like 200 - 250 Hz.
2. Look at horn loaded bass modules. The rest won't cut it, IME
3. Details on your tractrix project, please ?

Thanks

 

[CLS]

If loud and low at the same time is not needed, dipole can be considered, too. (Slot-loaded is prefereable.) This will need actively xover'ed and driven. In such situation, big power is actually not needed, it's limited by the available stroke of the woofer (which is easily bottomed out in this case). Such system can be very good if all things are well put together. (but it's not an easy task, though)

If no practical limitation, front loaded bass horn would be the best, no doubt.

 

[astrojet]

Hi guys. Thanks for the continuing thoughts.

Retsel: I thought about a Karlson for a bit, but didn't think the bass extension was very good. Maybe I'm mistaken.

CLS: Yeah, the SLPP suggested by tb46 looked very interesting. I'm still thinking I want something in stereo. The future might dictate that I use the ends of the long side of the room for placement. If so, the separation might be enough to emphasise any directivity. Two 12" or 15" per side seems like huge overkill. I did search around for 8" SLPP, thinking 4 X 8" might do the trick, but I didn't come up with anything.

Zobsky1: My very simple tests of sending frequency modulated sine waves from my laptop and measuring SPL variation on my smartphone suggests that just the opposite happened with the front horn! I tried to design the tractrix at 175 Hz, but the first corner seems to be at 150 Hz. I guess my final might not be exactly as sized in my calculations, or maybe the drivers are just getting re-broken in. They are Whiteley dual concentrics from about the 1950s. I had to revamp the surrounds, but now I'm really digging them. Picture attached at the end. I went back to the original papers and made my own calculations in Matlab based on TS measurements I made after about 3 days of very, very low volume workout on the vintage woofers. Who knows, maybe the calculations weren't current standard. I'm sure there is some logical reason they came out a bit 'low'. Irregardless, I am overjoyed by the sound. I'm comparing them side-by-side with some fostex frugal horns.... and I am certain I will NEVER go back to the frugalhorns.

Zobsky2: Do you consider tapped horns to be 'horn loaded'? Do you think Volvotreter's 38 Hz TH would cut it? I have no idea nor experience with them.

 

[CLS]

Well, mybe the terms are confusing here...

What I mentioned about 'slot-loaded' is open baffe dipole, with the apparent radiating area restricted by a 'window' of slot shape. It's still OB (dipole).

Interesting horn you have! Is the rear of driver open, or enclosed by a chamber?

 

[Inductor]

Peerless 830669 315 SWR in a W-frame (with pics and measurements)
Dipole subWoofer with Peerless SLS-315
The Renegade, dipole bass with open-baffle d'Appolito

(note: use google for translations)

 

[zobsky]

Zobsky2: Do you consider tapped horns to be 'horn loaded'? Do you think Volvotreter's 38 Hz TH would cut it? I have no idea nor experience with them.

I've built a couple of TH before. My suggestion would be to not bother with them when you're trying to cover both bass and midbass. They are essentially bandpass devices that typically work well over only one to two octaves. I've tried exactly what you propose (a tapped horn to cover about 40 - 180 Hz) and things got ugly after about 120 Hz (and no amount of tweaking or EQ could fix the issue).

My advice is to investigate a front loaded design (or maybe even rear loaded bass scoop) that can do about 35 Hz to 300 Hz. That should be easy enough. You could potentially use your frugelhorns as bass modules in the interim.

Karlson K15 do work very well (don't discount them) but they can be large and don't do the 20 - 40 Hz very well unless EQ'd

 

[tb46]

Hi astrojet,

I designed a transmission line sub for NWCgrad, and have been working on a slightly smaller version for my own use. It is designed for the LAB12, but will take other 12" drivers, e.g.: JBL GTO1214. The size will be: 23-15/16" x 23-15/16" x 16". The rsponse (LAB12) should end up being about -3dB from 35Hz-160Hz, or so (the actual upper extension would have to be measured - might go higher), about 108dB in the passband 1Pi @ 30W. It will take a little more time in AutoCAD to get it finished, I'll post it if you are interested.

Regards,