Help needed! Where to start with open baffle speakers

[fatmarley]

Believe me that Slawa would leave no stone unturned to get the best sound. He supplied his own crossovers using silver wiring throughout and top quality components such as Audionote capacitors etc. I cant give further details as

1. It would be unfair to plagiarise Slawa's IP
2. I don't really understand what was done

But they sure sound balanced across the frequency range.

Sounds like he must have used a better crossover than the standard one.

[fatmarley]

Other approaches that I think are flawed in terms of musicality are

1. Going active on the base with masses of EQ
2. Boxing in, or partly boxing in, the base driver, thus moving away from the freedom of a true open baffle.

Very surprised at your comment on going active In the bass. Although I've never tried It (yet), It seems like the logical thing to do.

Yes, I've heard open baffle bass (and midrange) Is supposed to be hard to beat. Just a shame you need so much baffle/cone area to get decent bass. There's also the fact that you have to lose a huge amount of efficiency to get some deep bass (assuming you want a flat response down to low frequencies).

[vintage60]

Thank you everyone! Too many to thank everyone in person so a group thanks to you all for your inputs.

I'm on holiday from this weekend so won't bother buying any books at the airport. Plenty to read up on following your suggestions.

I've heard of Slawa at SW1X - he lives quite close to me so I had been thinking of going over to his place to hear his OBs and to get some pointers from him.

From what I've heard, he takes his hifi very seriously and uses only top grade parts and materials.

Chris - I'm only 20 minutes from Bishops Stortford so would love to drop by one day and hear your speakers. Thank you for the kind offer.

I think I will start with something absurdly simple and work my way up. My mate Dave has built 10 OBs over the years and it is only his later ones that he was happy with. As he says, you need to build up the experience and knowledge and learn from trial and error.

Thank you all!

[bumpy]

Thank you everyone! Too many to thank everyone in person so a group thanks to you all for your inputs.

I'm on holiday from this weekend so won't bother buying any books at the airport. Plenty to read up on following your suggestions.

I've heard of Slawa at SW1X - he lives quite close to me so I had been thinking of going over to his place to hear his OBs and to get some pointers from him.

From what I've heard, he takes his hifi very seriously and uses only top grade parts and materials.

Chris - I'm only 20 minutes from Bishops Stortford so would love to drop by one day and hear your speakers. Thank you for the kind offer.

I think I will start with something absurdly simple and work my way up. My mate Dave has built 10 OBs over the years and it is only his later ones that he was happy with. As he says, you need to build up the experience and knowledge and learn from trial and error.

Thank you all!

OK Thiha when you're ready

[bumpy]

Very surprised at your comment on going active In the bass. Although I've never tried It (yet), It seems like the logical thing to do.

Over the years I have seen how adding more and more complexity robs the music of its magic. Its probably more about timing, than getting the frequencies right.

I have run active subs before on a horn based system - pair of expensive 15 inch drivers in stereo boxes set up with a TACT preamplifier. Tuning frequency curves and time alignment gave plenty of scope for adjustment and impressed casual visitors with low frequencies but it never hit the spot in terms of magic, reality, or relaxed listening. I have heard sounds like this at a Hi Fi shows recently and in the main was not impressed.

The key for me is that in general adding complexity to a Hi Fi system cannot add magic, only rob it. So simplicity, but of the highest quality you can afford, is best.

[RothwellAudio]

Very surprised at your comment on going active In the bass. Although I've never tried It (yet), It seems like the logical thing to do.

It seems to me like a very illogical thing to do. The bass effectively disappears because the "positive" bass in front of the baffle and the "negative" bass behind it cancel each other out. Infinite baffles - or sealed boxes - were invented to prevent the cancellation. Simply sending more bass to the driver via heavy EQ will just create more "negative" bass to cancel the "positive" bass - hence no net gain, just more stress for the driver.

[walpurgis]

The ultimate OB would vent rearwards LF through an exterior house wall, but then it would cease to be OB, but a true IB. (well nearly)

[fatmarley]

It seems to me like a very illogical thing to do. The bass effectively disappears because the "positive" bass in front of the baffle and the "negative" bass behind it cancel each other out. Infinite baffles - or sealed boxes - were invented to prevent the cancellation. Simply sending more bass to the driver via heavy EQ will just create more "negative" bass to cancel the "positive" bass - hence no net gain, just more stress for the driver.

What you're saying Is, If you turn up the volume on an open baffle bass driver, the "negative" bass will cancel the "positive" and It wont go any louder.


I think you were trying to say, don't use positive EQ to fill In the "dips" In the low frequency response. That's not what I was suggesting. If you build an open baffle bass driver you will have to use EQ, whether active or passive, to get a flat response. Obviously, you lower the peaks In the frequency response down until you get something near flat.
With active bass you can make EQ and crossover/phase adjustments to suit any room. You can change your mid/tweeters and not have to buy new passive components to make the system work as a whole. The components to make passive low pass filters on bass drivers are usually big and expensive, so any mistakes here would be costly and time consuming (good quality, low DCR Inductors are often hand made).
The other advantage of active bass Is that you can make adjustment 'on-the-fly', so It's far quicker and easier to get the crossover sorted.

[SW1X]

Thank you everyone! Too many to thank everyone in person so a group thanks to you all for your inputs.

I'm on holiday from this weekend so won't bother buying any books at the airport. Plenty to read up on following your suggestions.

I've heard of Slawa at SW1X - he lives quite close to me so I had been thinking of going over to his place to hear his OBs and to get some pointers from him.

From what I've heard, he takes his hifi very seriously and uses only top grade parts and materials.

Chris - I'm only 20 minutes from Bishops Stortford so would love to drop by one day and hear your speakers. Thank you for the kind offer.

I think I will start with something absurdly simple and work my way up. My mate Dave has built 10 OBs over the years and it is only his later ones that he was happy with. As he says, you need to build up the experience and knowledge and learn from trial and error.

Thank you all!

Greetings,

Just noticed this thread.

Building speakers is easy- building speakers to reproduce music at its maximum musical performance is hard. If time and cost is not a constraint, I would highly recommend to start building your own speakers as every material and its environment contributes to its unique sound signature. On top of that everybody has different expectations anyway. So "one size fits all" approach does not really work with speakers. Open back speakers are heavily affected the room size & shape as the room becomes the extension of the speakers even more so than with closed cabinet designs.

Knowledge is everything and experimentation is the key. Having said that most of the OB speakers I have seen over the years have major flaws in either their design or their implementation, original P17 including.

The most common flaw is the choice of drivers, their position and the proportion/size of the cabinets resulting in thin, lame or/and dissonant sounding mid-bass- the most import frequency range when reproducing music.

Using active X-over, EQ compensation and active woofers to compensate the short comings of bass is a sub optimal approach. In 9.9 out of 10 cases, it results in dissonance in the mid-bass area.

S

[RothwellAudio]

What you're saying Is, If you turn up the volume on an open baffle bass driver, the "negative" bass will cancel the "positive" and It wont go any louder.

I'm really saying that the bass limit is set by the size of the baffle and trying to compensate for a tiny baffle by using massive EQ isn't a great idea.
Of course, you're quite correct that active EQ for crossover slopes and fine tuning etc. is perfectly valid.