Image caption Imogen Heap remortgaged her flat to fund her second album in 2005

When singer-songwriter Imogen Heap tweeted last week that she may stop touring because it is too expensive and it was "not easy keeping afloat in this climate", it was an unexpected message of gloom from one of the UK's most acclaimed artists.

It was more surprising because Heap has just won a Grammy and a prestigious Ivor Novello songwriting award, and her substantial fanbase is among the most devoted and active in music.

And it pricked the music industry myth that live music is drawing more punters and dollars than ever, making up for the ongoing slump in album sales.

So if Heap is struggling to make ends meet, what chance do other musicians have?

"I need to feed myself and this isn't going to help me, if I keep touring till the end of the year like I wanted to," she says, speaking on the phone before a gig in Miami, part of her current US tour.

"I just can't afford it. I'm going to be broke."

Image caption Heap won a Grammy for best engineered album, non-classical

In her revealing tweets, she told fans "this may be the last tour in a while", that it was "so expensive to tour!" and "record sales low (across the industry) really impacting me".

She was on "a downer", she says, after being told by her manager that she needed to find an extra £20,000 to stage the European tour she was hoping to play later this year.

"At this point in my life, I just about break even when it comes to touring," she explains. "But with the European tour that I was about to do, it turns out that even just doing it at a basic no-frills level, I would still be £20,000 out of pocket."

Heap remortgaged her flat to set up her own record label and release her second album, Speak for Yourself, in 2005. The follow-up, Ellipse, reached number five in the US chart last year.

During our conversation, she is keen to look on the bright side and not appear to moan. But she does point to several factors that have made life tough as a working musician.

First, the slide in record sales in recent years has left a noticeable dent in her bank balance.

"Even though the popularity and the fanbase is much much greater, and more people have heard about me through things like the Grammys and the Ivors and touring and word of mouth, it doesn't reflect in he sales of the record and doesn't go into my pocket."

I'm not Britney and not playing stadiums - I'm in the middle, and there are a lot of bands like me where it really is hard to get over the hump

Then there is the recession. Some fans have been unable or unwilling to pay $40 (£27) a ticket for her current tour, and she blames venue owners, ticket agencies and promoters for bumping up the fees.

Of that price, she will get around $16 (£11) per person to cover all touring costs, she says.

"So many venues are owned by these various different ticketing and promoting people, and they're all in bed with one another. It's no secret over here," she says.

Although she is reluctant to name names, the newly merged Live Nation and Ticketmaster owns half the venues on her 23-date North American tour and is selling tickets for most.

Heap is playing in mid-sized venues, holding mostly between 2,000-3,000 people.

The only other option is to play more shows in more intimate, independent venues. "But it would take three or four times as long to do the tour and that's just not feasible", she says.

Image caption Imogen Heap: The fans really are behind her

The extra time required would give her less chance to write new material. "And the writing of songs for me or other people, or producing other people, that's where the cash comes in. It was a decision I was having to make."

The singer deftly sums up the predicament: "I'm not Britney and not playing stadiums. I'm in the middle, and there are a lot of bands like me where it really is hard to get over the hump."

In fact, Heap's biggest money-spinner of recent years has come from a sample of her song Hide and Seek, which was used in US R&B star Jason Derulo's chart-topping hit Whatcha Say.

"He's sold, like, two-and-a-half million copies of that song," Heap says. "Which is fantastic for me because I get half of it."

Production costs

In the wake of her comments on Twitter, some have suggested she cut down the production costs for her elaborate live show. For her part, she says she wants to give fans the gig of their lives.

Another blunt explanation for Heap's situation is that not enough people like her music.

But given her status and success, it would be a disaster if artists like her were unable to ply their trade.

So she is looking to more innovative solutions to stay on the road.

A recent gig in Indonesia showed a possible way forward. The singer had never visited or paid attention to the country - until a deluge of tweets from Indonesian fans.

That was the first she knew of the large fanbase there, and resulted in a sold out gig to 4,000 fans in Jakarta.

My biggest asset is not cash - it's a large, growing, devout fanbase

"That was the power of what I need to harness, this incredible word of mouth," she says. "That one did make money. That one we got it right."

The singer now wants to put a map on her website so fans can ask her to come to their country or city, pledging money in advance.

"Eventually I will get to you, but I need to know that you're there for me when I get there," she says.

And her 1.5 million followers on Twitter helped out again after her recent comments about touring.

One fan pointed her towards Pledge Music, a service that lets artists raise money for new projects by selling exclusive goodies such as backstage passes, access to rehearsals and signed merchandise.

She is now likely to go down that route to raise the £20,000 she needs to tour Europe.

"My biggest asset is not cash - it's a large, growing, devout fanbase," Heap says.

"It's not about making tonnes of cash. It's just about being able to go and do a show for the people that really want to see it."