Which enclosure for best bass performance?

[danny_66]

However I would have to design my own crossover for it and without measurement tools I'd rather stick to a ready made trusted design.

Correct and wise decision!
Without simulation and measurement tools it's impossible to create a good speaker. You'll just waist time and money.

Those M1 look impressive, 100db sensitive ! Nice

 

[Charles Darwin]

An other option would be a lower priced clone of the Daniel Hertz M1.
Perhaps in the future...

Somewhere I read that the M1 uses all Beyma drivers (could have been here, it certainly looks like a Beyma horn though), if true you could build an exact copy for under €2000.

 

[fakeout]

Correct and wise decision!
Without simulation and measurement tools it's impossible to create a good speaker. You'll just waist time and money.

Those M1 look impressive, 100db sensitive ! Nice

Are there free simulation tools?

 

[forr]

Low Qts woofer in horn enclosure.
High Qts woofer in sealed enclosure.

Low Qts woofers tend to have weak bass, but when done properly/successfully, the quality of the bass is usually better than high Qts woofers.

A low Qtc and a 6 dB/octave bass "shelf" boost is a way to lower the limit of bass zone and get a very clean lower end. Starting with a driver in a closed box with fc = 50 Hz or less, and Qtc = 0.4 and providing it with a bass boost may provide excellent results. An artificial low Qtc can be obtained through electronics means, for instance a parametric filter. This a kind of transform.

 

[forr]

Are there free simulation tools?

For closed and BR boxes, this simple one is pretty :
Speakerbuilder Pro 2.0

 

[danny_66]

Are there free simulation tools?

Boxsim, download link english version
You can import the measured frequency responses and the impedance curves for accurate simulations.

 

[LineSource]

Somewhere I read that the M1 uses all Beyma drivers .

A review of the Daniel Hertz M1 noted that all Beyma drivers were used. 18db crossovers at 80Hz between 18"-12" and 1600Hz to a 60x40 horn. The review stated that the 12" speaker polar response was near 60 degrees at 1600Hz, and this matched the selected horn+compression driver.

Many old-school JBL and modern monitors use an 18" woofer with LR4 Xovers at 80-100Hz to 10" midbass with steep Xover at 1100-1200Hz to 90x40 horn(SEOS). The polar of many 10" at 1100-1400 matches a 90x40 polar pattern. A 10" midbass like the Lambda TD10M is a cult favorite.


Intermodulation distortion, often called Dopler distortion, from mixing high freq + low freq on one cone is a problem when a midbass is demanded to cover a wide bandwidth. There are free spreadsheet tools for Dopler distortion on the web which estimate this effect.

 

[Charles Darwin]

Thanks LineSource!
That's what I've seen, just don't remember where.
Adds up to about £1200 in drivers for the pair without VAT.

 

[Scott L]

Bass Reflex 3 way

I have decided that I will go with a constant directivity design.
That means midrange and tweeter directivity have to match precisely.
Usually those designs have crossover frequencies between 700-2500Hz depending on the midrange size.
One of my plans was with the Delta12LFa, Beyma 6MI90 midrange and SEOS6 or 8 with a Denovo CD and crossover frequencies at 500Hz and 2500Hz approximately.
That would be almost perfect as it would be ideal for a center channel as well. However I would have to design my own crossover for it and without measurement tools I'd rather stick to a ready made trusted design.
An other option would be a lower priced clone of the Daniel Hertz M1.
Perhaps in the future...

Be sure to notch out that 2k bump of the Eminence Delta 12LFa, even if you only use it to 500Hz (which is an excellent idea). Active filters stomp all over passives; decent amps are affordable these days. A 3.6 cubic foot enclosure should work fine. See Jerry McNutt design.

http://www.parts-express.com/pedocs/more-info/290-416-eminence-delta-12lfa-more-info.pdf