Waveguide design - Help needed

[fatmarley]

Hi Guys,

It's interesting that Audio-note are one of the most popular speakers at hifi shows (8" 2 way paper speakers with foam surrounds) The hifi forum (HiFi WigWam) organised a show and members took along their systems to 'show off'. A lot of people mentioned that the standmount, Snell Ks (Pre Audio note speakers) made some of the most enjoyable sounds - I know at least two pairs of Snell Ks were at the show.

I think a reasonably compact, acoustic suspension speaker, with and 8" paper cone and foam surround, (like the Snell K) but coupled with a waveguide tweeter, would be perfect for my needs. You can still buy the 8" paper driver that was used in the Snell K ( eBay link ). I would like a waveguide tweeter because of the beeter off-axis response and i read over on Troels gravesen website (LINK) that a waveguided tweeter coupled with a first order crossover, gives excellent presence.

I was thinking, a cheap way of experimenting with a design like this would be to buy some cheap Heybrook HB1 or JPW P1, AP2 or AP3s (around £70), fit a waveguide tweeter and a new crossover. Perhaps something like the Monacor DT300 with the associated WG300 waveguide: LINK would do the job ?

I have a Dayton Woofer Tester 3 here for measuring drivers, but I don't have anything for measuring the frequency response or the knowledge required to design the crossovers. From what i've read, I would need a calibrated Behringer ecm8000 microphone and power supply.

If I got the microphone, would someone here be able to help me design a crossover ?

[fatmarley]

Hmmm - From the lack of response, i'd say this is more complicated than i'd hoped.

Well, i've found out what i'd need to buy:

Cross·Spectrum - Calibrated Behringer ECM8000 Measurement Microphones

Blue Microphones Icicle XLR To USB Converter: Amazon.co.uk: Musical Instruments

On Stage Stand Euro Boom Mic Stand Ms7701b Black

TrueRTA Audio Spectrum Analyzer Software

[WithTarragon]

Well, it is complicated and your questions are quite open-ended. I suspect that is why no has repsonded, since no one would know where to start.

My suggestion is that you imitate or copy a proven design that DIYers have already tackled. Use that as your first build.

The choice of parts and the design of a crossover are both large and complicated topics. It is not something that you can casually and quickly pick up.

Very importantly, you have not mentioned anything about budget. Perhaps a kit might be best for your project. There are many available and some of the vendors/designers are quite knowlegible and helpful.

Good luck.

[MunkeyQ]

I'm actually doing a very similar build - 8" Volt woofer, QSC conical CD waveguide and Celestion compression driver.

The main snag so far was finding a woofer which goes up high enough, cleanly. Due to the size, the QSC only loads down to 2.2khz...so the woofer needs to meet that without sounding too nasty. However, the Volts do that effortlessly.

As Tarragon mentioned, the crossover is no mean feat. Going active with a processor is the best way if you're useless at passive design like I am.

[fatmarley]

Originally Posted by WithTarragon

Well, it is complicated and your questions are quite open-ended. I suspect that is why no has repsonded, since no one would know where to start.

Sorry, that's typical of me. I'm really bad at explaining things.

Originally Posted by WithTarragon

My suggestion is that you imitate or copy a proven design that DIYers have already tackled. Use that as your first build.

That's kind of what I want to do. But i'd rather modify a proven design, by adding a better tweeter, and I think Heybrook HB1s would be perfect for modifying.

Originally Posted by WithTarragon

The choice of parts and the design of a crossover are both large and complicated topics. It is not something that you can casually and quickly pick up.

I was hoping to use the Monacor DT 300 because it's cheap and if possible i'd like to use it with a first order crossover. Troels Gravesen used it with a first order crossover in one of his designs, so I was hoping I could do the same.

The Heybrook HB1 crosses over at 5kHz with a simple first order crossover IIRC, so I assume the woofer has plenty of room for crossover overlap. I think the HB1 woofer trades bass extension for high frequency extension.

Originally Posted by WithTarragon

Very importantly, you have not mentioned anything about budget. Perhaps a kit might be best for your project. There are many available and some of the vendors/designers are quite knowlegible and helpful.

Budget, say three hundred quid max.

If I could find a 2 way kit that used an 8" paper coned woofer (preferably with a foam surround) in a sealed box, that was pretty sensitive (around 90db) and easy to drive. I also want it to work well close to a wall and have a waveguide tweeter.

The nearest I can find is the Gedlee Harper but it's quite expensive and has very little bass.

Originally Posted by WithTarragon

Good luck.

Cheers, I think i'm going to need it...

[fatmarley]

Originally Posted by MunkeyQ

I'm actually doing a very similar build - 8" Volt woofer, QSC conical CD waveguide and Celestion compression driver.

The main snag so far was finding a woofer which goes up high enough, cleanly. Due to the size, the QSC only loads down to 2.2khz...so the woofer needs to meet that without sounding too nasty. However, the Volts do that effortlessly.

As Tarragon mentioned, the crossover is no mean feat. Going active with a processor is the best way if you're useless at passive design like I am.

Is the volt driver made of paper ? and is it going to be a sealed box design ? If so, i'd be very interested in your design.

[MunkeyQ]

Why paper? It's even more difficult to find a paper coned driver which goes cleanly to 2khz.

The Volts are doped polypropylene, and no, it's not going to be sealed as their parameters suit a vented alignment better.

[PeterDupont]

Why not go for a used, old Snell Type K - the one Audio Note UK have tried to copy with only marginal succes.

[PeterDupont]

Btw., the famous and highly expensive AN tweeters can be found here:

Tonegen / Foster 15069-61A 1-inch soft dome tweeter | PR Audio

45$ pr. pair.

[fatmarley]

Originally Posted by MunkeyQ

Why paper? It's even more difficult to find a paper coned driver which goes cleanly to 2khz.

The Volts are doped polypropylene, and no, it's not going to be sealed as their parameters suit a vented alignment better.

I know it's weird, but I prefer the sound of paper drivers to polypropylene. The best polypropylene speakers i've ever owned were some 10" Tannoy studio monitors, they were great but a little bit too smooth for rock music.